Petroleum Experts
PROSPER
Single Well Systems Analysis
Version 8
October, 2003
USER GUIDE
The information in this document is subject to change as major improvements and/or
amendments to the program are generated. When necessary, Petroleum Experts will issue the
proper documentation.
The software described in this manual is furnished under a licence agreement. The software
may be used or copied only in accordance with the terms of the agreement. It is against the
law to copy the software on any medium except as specifically allowed in the license
agreement. No part of this documentation may be reproduced or transmitted in any form or by
any means, electronic or mechanical, including photocopying, recording, or information storage
and retrieval systems for any purpose other than the purchaser's personal use, unless express
written consent has been given by Petroleum Experts Limited.
All names of companies, wells, persons or products contained in this documentation are part of
a fictitious scenario or scenarios and are used solely to document the use of a Petroleum
Experts product.
Address:
Petroleum Experts Limited
Spectrum House
2 Powderhall Road
Edinburgh, Scotland
EH7 4GB
Tel : (44 131) 474 7030
Fax : (44 131) 474 7031
Email : edinburgh@petex.com
Web Site: http://www.petex.com
Registered Office:
Petroleum Experts Limited
Spectrum House
2 Powderhall Road
Edinburgh, Scotland
EH7 4GB
1 - 12
TABLE OF CONTENTS
1
Introduction .................................................................................................................................................... 1
1.1
Using PROSPER ........................................................................................................................................... 1
1.2
PROSPER and Systems Analysis ................................................................................................................. 4
1.2.1 A Note About PROSPER ............................................................................................................................... 5
1.3
1.3.1
1.3.2
1.3.3
1.3.4
1.3.5
1.3.6
1.3.7
1.3.8
1.3.9
1.3.10
1.3.11
1.3.12
1.3.13
1.3.14
2
Examples ....................................................................................................................................................... 7
Example 1 – Naturally Flowing Oil Well ......................................................................................................... 7
Example 2 – Gas Lift Design.......................................................................................................................... 7
Example 3 – Well and Flowline Modelling...................................................................................................... 7
Example 4 – Temperature Prediction............................................................................................................. 8
Example 5 – ESP Lifted Well ......................................................................................................................... 8
Example 6 – HSP Lifted Well ......................................................................................................................... 8
Example 7 – Retrograde Condensate Well.................................................................................................... 9
Example 8 – Gravel Packed well ................................................................................................................... 9
Example 9 – Horizontal Well – Friction dP..................................................................................................... 9
Example 10 – Multi-Layer dP Pressure Loss ................................................................................................. 9
Example 11 – Multi-lateral well .................................................................................................................... 10
Example 12 – Modelling of a smart well completion using multilateral option in PROSPER........................ 10
Example 13 – Gas injector with downhole chokes using multilateral model ................................................ 10
Example 14 – Multilateral model including PCP........................................................................................... 10
Installation...................................................................................................................................................... 1
2.1
2.1.1
2.1.2
2.1.3
System Requirements.................................................................................................................................... 1
Hardware ....................................................................................................................................................... 1
Software......................................................................................................................................................... 2
Upgrading From a Previous Version .............................................................................................................. 2
2.2
2.2.1
2.2.2
2.2.3
Installing PROSPER ...................................................................................................................................... 3
What Setup Does........................................................................................................................................... 3
Configuration file (PROSPER.INI).................................................................................................................. 4
Key drivers for Windows 98, NT, 2000, ME ................................................................................................... 4
2.3
Accessing PROSPER .................................................................................................................................... 5
2.3.1 Connecting the software protection key ......................................................................................................... 5
2.3.2 Creating the PROSPER Icon ......................................................................................................................... 5
2.4
REMOTE Software Key Utility........................................................................................................................ 6
2.4.1 Entering the Authorisation Code .................................................................................................................... 6
2.4.2 Updating the Software Protection Key ........................................................................................................... 8
2.5
PROSPER Sample Files................................................................................................................................ 9
2.6
Program Check List........................................................................................................................................ 9
2.6.1 Smart Menus.................................................................................................................................................. 9
PETROLEUM EXPERTS LTD
TABLE OF CONTENTS
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4
2 - 12
File Management ....................................................................................................................................................... 1
3.1
3.1.1
3.1.2
3.1.3
3.1.4
3.1.5
3.1.6
3.1.7
3.1.8
PROSPER Files............................................................................................................................................. 1
PVT Data (*.PVT)........................................................................................................................................... 1
Input Data (*.SIN)........................................................................................................................................... 1
Analysis Data (*.ANL) ................................................................................................................................... 2
Output Data (*.OUT) ..................................................................................................................................... 2
Creating a New File........................................................................................................................................ 3
Opening an Existing File ................................................................................................................................ 3
Saving a File .................................................................................................................................................. 4
Copying a File ................................................................................................................................................ 4
3.2
3.2.1
3.2.2
3.2.3
3.2.4
3.2.5
3.2.6
Preferences.................................................................................................................................................... 5
Screen............................................................................................................................................................ 5
File ................................................................................................................................................................. 7
Plot................................................................................................................................................................. 8
User Applications ......................................................................................................................................... 10
Limits............................................................................................................................................................ 11
Units............................................................................................................................................................. 12
3.3
Software Key Maintenance .......................................................................................................................... 12
3.4
User Correlations ......................................................................................................................................... 13
3.5
3.5.1
3.5.2
3.5.3
3.5.4
3.5.5
3.5.6
Printing......................................................................................................................................................... 14
Preparing to Print ......................................................................................................................................... 14
Selecting a Printer........................................................................................................................................ 14
Printing Export Data ..................................................................................................................................... 15
Selecting a Exported Data to Print ............................................................................................................... 17
Word Processing in PROSPER ................................................................................................................... 17
Clipboard Command .................................................................................................................................... 17
3.6
Command Buttons ....................................................................................................................................... 18
Data Input - General .................................................................................................................................................. 1
4.1
4.1.1
4.1.2
4.1.3
4.1.4
4.1.5
4.1.6
4.1.7
4.1.8
4.1.9
4.1.10
PROSPER Main Menu................................................................................................................................... 1
File ................................................................................................................................................................. 2
Options........................................................................................................................................................... 2
PVT ................................................................................................................................................................ 2
System ........................................................................................................................................................... 2
Matching ........................................................................................................................................................ 2
Calculation ..................................................................................................................................................... 2
Design............................................................................................................................................................ 2
Output ............................................................................................................................................................ 2
Units............................................................................................................................................................... 3
Help................................................................................................................................................................ 3
4.2
Options Selection........................................................................................................................................... 4
4.2.1 Fluid Description ............................................................................................................................................ 5
4.2.1.1 Fluid .......................................................................................................................................................... 5
4.2.1.2 Method ...................................................................................................................................................... 5
4.2.1.3 Equation of State....................................................................................................................................... 5
4.2.1.4 Separator .................................................................................................................................................. 6
4.2.1.5 Emulsions.................................................................................................................................................. 6
4.2.1.6 Hydrates.................................................................................................................................................... 6
4.2.1.7 Water Viscosity.......................................................................................................................................... 6
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4.2.1.8 Water Vapour ............................................................................................................................................ 6
4.2.2 Well ................................................................................................................................................................ 7
4.2.2.1 Flow Type.................................................................................................................................................. 7
4.2.2.2 Well Type .................................................................................................................................................. 7
4.2.3 Artificial Lift..................................................................................................................................................... 7
4.2.3.1 Method ...................................................................................................................................................... 7
4.2.3.2 Type .......................................................................................................................................................... 7
4.2.4 Calculation Type ............................................................................................................................................ 8
4.2.4.1 Predict ....................................................................................................................................................... 8
4.2.4.2 Model ........................................................................................................................................................ 9
4.2.4.3 Calculation .............................................................................................................................................. 10
4.2.4.4 Output ..................................................................................................................................................... 10
4.2.5 Well Completion........................................................................................................................................... 10
4.2.5.1 Type ........................................................................................................................................................ 10
4.2.5.2 Gravel Pack............................................................................................................................................. 10
4.2.6 Reservoir...................................................................................................................................................... 11
4.2.6.1 Type ........................................................................................................................................................ 11
4.2.6.2 Gas Coning ............................................................................................................................................. 11
4.2.7 Header Information ...................................................................................................................................... 11
5
PVT Data Input .......................................................................................................................................................... 1
5.1
Introduction .................................................................................................................................................... 1
5.2
Black Oil - Oil and Water................................................................................................................................ 3
5.2.1 Input Data ...................................................................................................................................................... 3
5.2.1.1 Emulsions.................................................................................................................................................. 3
5.2.2 Tables ............................................................................................................................................................ 4
5.2.3 Match Data..................................................................................................................................................... 5
5.2.4 Regression..................................................................................................................................................... 6
5.2.4.1 Match ........................................................................................................................................................ 6
5.2.4.2 Match All ................................................................................................................................................... 7
5.2.4.3 Parameters................................................................................................................................................ 7
5.2.4.4 Viewing the Match Parameters ................................................................................................................. 7
5.2.4.5 Matching FVF above Bubble Point............................................................................................................ 8
5.2.5 Calculations ................................................................................................................................................... 8
5.2.5.1 Calculating PVT Data ................................................................................................................................ 8
5.2.5.2 Displaying the Calculated Data on the screen......................................................................................... 10
5.2.5.3 Plotting the Calculated Data.................................................................................................................... 11
5.2.5.4 Saving PVT tables from Calculated Data ................................................................................................ 11
5.2.6 Saving the PVT Data.................................................................................................................................... 12
5.2.7 Recalling a PVT File..................................................................................................................................... 12
5.2.8 Correlations.................................................................................................................................................. 12
5.2.9 Composition ................................................................................................................................................. 12
5.2.10 Non-Newtonian Fluid.................................................................................................................................... 14
5.2.11 Emulsions .................................................................................................................................................... 15
5.2.12 Hydraulic Pump Power Fluid Data .............................................................................................................. 17
5.2.13 Hydrates Formation table............................................................................................................................. 18
5.3
Black Oil - Dry And Wet Gas........................................................................................................................ 20
5.3.1 Input Data .................................................................................................................................................... 20
5.3.2 Match Data................................................................................................................................................... 21
5.4
Black Oil - Retrograde Condensate ............................................................................................................. 22
5.4.1 Input Data .................................................................................................................................................... 22
5.4.2 Match Data................................................................................................................................................... 23
5.4.3 Calculations ................................................................................................................................................. 23
5.5
Equation Of State - All Fluids ....................................................................................................................... 24
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7
4 - 12
Equipment Data Input ................................................................................................................................................ 1
6.1
6.1.1
6.1.2
6.1.3
6.1.4
6.1.5
Predicting Pressure Only ............................................................................................................................... 1
Deviation Survey............................................................................................................................................ 2
Surface Equipment......................................................................................................................................... 5
Downhole Equipment ..................................................................................................................................... 7
Temperature Survey ...................................................................................................................................... 9
Summary...................................................................................................................................................... 10
6.2
6.2.1
6.2.2
6.2.3
6.2.4
6.2.5
6.2.6
6.2.7
Predicting Pressure and Temperature (Enthalpy Balance) .......................................................................... 11
Deviation Survey.......................................................................................................................................... 12
Surface Environment.................................................................................................................................... 12
Drilling and Completion ................................................................................................................................ 13
Lithology....................................................................................................................................................... 14
Surface Equipment....................................................................................................................................... 15
Downhole Equipment ................................................................................................................................... 18
Databases.................................................................................................................................................... 20
6.3
6.3.1
6.3.2
6.3.3
6.3.4
6.3.5
Rough Approximation................................................................................................................................... 21
Deviation Survey.......................................................................................................................................... 22
Surface Equipment....................................................................................................................................... 23
Downhole Equipment ................................................................................................................................... 23
Geothermal Gradient.................................................................................................................................... 24
Average Heat Capacities ............................................................................................................................. 25
6.4
6.4.1
6.4.2
6.4.3
6.4.4
6.4.5
Improved Approximation .............................................................................................................................. 25
Deviation Survey.......................................................................................................................................... 26
Surface Equipment....................................................................................................................................... 26
Downhole Equipment ................................................................................................................................... 27
Geothermal Gradient.................................................................................................................................... 27
Sea Temperature Gradient .......................................................................................................................... 28
IPR Data Input ........................................................................................................................................................... 1
7.1
IPR Single Well Data Entry ............................................................................................................................ 1
7.1.1 The Main Data Entry Screen............................................................................................................................. 2
7.1.2 Action Buttons................................................................................................................................................... 3
7.1.3 Model Selection Screen .................................................................................................................................... 4
7.1.4 Data Input Screen ............................................................................................................................................. 5
7.2
IPR Models for Oil Wells ................................................................................................................................ 7
7.2.1 P.I. Entry ........................................................................................................................................................... 7
7.2.2 Vogel................................................................................................................................................................. 8
7.2.3 Composite......................................................................................................................................................... 8
7.2.4 Darcy................................................................................................................................................................. 8
7.2.5 Fetkovich........................................................................................................................................................... 9
7.2.6 Multi-rate Fetkovich........................................................................................................................................... 9
7.2.7 Jones ................................................................................................................................................................ 9
7.2.8 Multi-rate Jones ................................................................................................................................................ 9
7.2.9 Transient ........................................................................................................................................................... 9
7.2.10 Hydraulically Fractured Well ......................................................................................................................... 10
7.2.11 Horizontal Well - No Flow Boundaries .......................................................................................................... 10
7.2.12 Horizontal Well - Constant Pressure Upper Boundary .................................................................................. 11
7.2.13 Multi-Layer Inflow.......................................................................................................................................... 12
7.2.14 External Entry ............................................................................................................................................... 13
7.2.15 Horizontal well - dP Friction .......................................................................................................................... 14
7.2.16 Multi-Layer - dP Loss .................................................................................................................................... 17
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7.2.17 SkinAide........................................................................................................................................................ 18
7.2.18 Dual Porosity................................................................................................................................................. 19
7.2.19 Horizontal Well with Transverse Vertical Fractures....................................................................................... 19
7.2.20 Thermally Induced Fracture Model ............................................................................................................... 19
7.2.20.1 Overview ................................................................................................................................................. 19
7.2.20.2 Data Entry ............................................................................................................................................... 20
7.2.21 Using Relative Permeabilities in PROSPER ................................................................................................. 21
7.2.22 Coning Calculation........................................................................................................................................ 25
7.3
IPR for Gas and Retrograde Condensate .................................................................................................... 26
7.3.1 Jones .............................................................................................................................................................. 26
7.3.2 Forcheimer...................................................................................................................................................... 26
7.3.3 Back Pressure................................................................................................................................................. 27
7.3.4 C and n ........................................................................................................................................................... 27
7.3.5 Multi-rate C and n ........................................................................................................................................... 27
7.3.6 Multi-rate Jones .............................................................................................................................................. 27
7.3.7 External Entry ................................................................................................................................................. 27
7.3.8 Petroleum Experts .......................................................................................................................................... 28
7.3.9 Hydraulically Fractured Well ........................................................................................................................... 29
7.3.10 Horizontal Well - No-Flow Boundaries .......................................................................................................... 29
7.3.11 Multi-layer Inflow ........................................................................................................................................... 29
7.3.12 Horizontal Well - dP Friction.......................................................................................................................... 30
7.3.13 Dual Porosity................................................................................................................................................. 30
7.3.14 Horizontal Well with Transverse Vertical Fractures....................................................................................... 30
7.4
Skin Models ................................................................................................................................................. 31
7.4.1 Mechanical/Geometrical Skin.......................................................................................................................... 31
7.4.2 Deviation/Partial Penetration Skin................................................................................................................... 34
7.5
Gravel Packed Completions......................................................................................................................... 35
7.6
Injection Wells.............................................................................................................................................. 37
7.7
SkinAide....................................................................................................................................................... 38
7.7.1 SkinAide Theoretical Background ................................................................................................................... 38
7.7.1.1 Position of the producing interval with respect to reservoir geometry ..................................................... 38
7.7.1.2 Interference between perforations and the damaged zone ..................................................................... 38
7.7.1.3 The Crushed Zone .................................................................................................................................. 39
7.7.1.4 Perforation tunnel which penetrates the formation .................................................................................. 40
7.7.1.5 Perforation tunnel through the casing and cement.................................................................................. 40
7.7.1.6 Annulus between Casing and Screen ..................................................................................................... 40
7.7.1.7 Hemispherical Flow Model ...................................................................................................................... 41
7.7.2 Using SkinAide................................................................................................................................................ 41
7.7.2.1 Flow Model.............................................................................................................................................. 42
7.7.2.2 Skin Model .............................................................................................................................................. 42
7.7.2.3 Perforation Data ...................................................................................................................................... 43
7.7.2.4 Geometry ................................................................................................................................................ 43
7.7.2.5 Petrophysics............................................................................................................................................ 45
7.7.2.6 Damaged Zone........................................................................................................................................ 46
7.7.2.7 Cased Hole.............................................................................................................................................. 46
7.7.2.8 Crushed Zone.......................................................................................................................................... 47
7.7.2.9 Perforations............................................................................................................................................. 48
7.8
Multi-Lateral Interface .................................................................................................................................. 53
7.8.1 Network Interface............................................................................................................................................ 53
7.8.1.1 Motivation................................................................................................................................................ 53
7.8.1.2 Interface Overview .................................................................................................................................. 53
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7.8.1.2.1
Network Window..................................................................................................................... 55
7.8.1.2.2
The Navigator Window ........................................................................................................... 57
7.8.1.2.3
Toolbar Details ....................................................................................................................... 57
7.8.1.2.4
Network Manipulation ............................................................................................................. 59
7.8.1.2.5
Menu Details........................................................................................................................... 59
7.8.1.2.6
Visualisation Screens ............................................................................................................. 63
7.8.2 Data Entry ....................................................................................................................................................... 64
7.8.2.1 Overview ................................................................................................................................................. 64
7.8.2.2 Tie-point and Junction Data .................................................................................................................... 64
7.8.2.3 Tubing Data............................................................................................................................................. 65
7.8.2.4 Completion Data...................................................................................................................................... 65
7.8.2.5 Reservoir Data ........................................................................................................................................ 65
7.8.3 Example of How to Set Up a Simple System .................................................................................................. 66
7.8.3.1 Introduction ............................................................................................................................................. 66
7.8.3.2 Place the Nodes in the Network Window ............................................................................................... 67
7.8.3.3 Connect the Nodes.................................................................................................................................. 67
7.8.3.4 Enter the Data ......................................................................................................................................... 68
7.8.3.5 Visualise / Calculate ................................................................................................................................ 69
8
Artificial Lift Data Input ............................................................................................................................................... 1
8.1
8.1.1
8.1.2
8.1.3
8.1.4
8.1.5
Gas Lift Input Data ......................................................................................................................................... 1
Fixed Depth Of Injection................................................................................................................................. 2
Optimum Depth of Injection............................................................................................................................ 2
Valve Depth Specified.................................................................................................................................... 3
Gas Lift (Safety Equipment) ........................................................................................................................... 4
Gas Lift (Allow injection in Pipe Line above wellhead) ................................................................................... 4
8.2
ESP Input Data .............................................................................................................................................. 6
8.3
HSP Input Data .............................................................................................................................................. 9
8.4
Progressive Cavity Pumps ........................................................................................................................... 11
8.4.1 PCP Input Data ............................................................................................................................................ 12
8.5
9
Gas Lift with coil tubing ................................................................................................................................ 13
Matching Menu .......................................................................................................................................................... 1
9.1
A Note on VLP Correlation Applications ........................................................................................................ 2
9.2
Correlation Comparison ................................................................................................................................. 4
9.3
QuickLook for Gas Lift.................................................................................................................................... 7
9.3.1 Input ............................................................................................................................................................... 7
9.3.2 Performing the QuickLook Calculation......................................................................................................... 10
9.4
QuickLook for ESP....................................................................................................................................... 12
9.4.1 Input ............................................................................................................................................................. 12
9.4.2 Performing the QuickLook Calculation......................................................................................................... 13
9.5
QuickLook for HSP....................................................................................................................................... 16
9.5.1 Input ............................................................................................................................................................. 16
9.5.2 Performing the QuickLook Calculation......................................................................................................... 17
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9.6
VLP/IPR Match and Quality Check .............................................................................................................. 19
9.6.1 VLP Matching............................................................................................................................................... 20
9.6.2 IPR Matching ............................................................................................................................................... 23
10
9.7
Gradient Match ............................................................................................................................................ 25
9.8
Surface Pipe Matching ................................................................................................................................. 27
9.9
Vertical Pipe Parameters ............................................................................................................................. 28
9.10
Surface Flow line Parameters ...................................................................................................................... 28
9.11
Correlation Thresholds................................................................................................................................. 28
Calculation Menu.................................................................................................................................................... 1
10.1
Calculation Options For Predicting Pressure Only or Rough/Improved Approximation Temperature Cases. 2
10.1.1 Inflow (IPR) .................................................................................................................................................... 2
10.1.2 System (VLP + IPR)....................................................................................................................................... 5
10.1.3 Left - Hand Intersection for VLP/IPR curves .................................................................................................. 6
10.1.3.1 Sensitivity Variables Screen...................................................................................................................... 6
10.1.3.2 Generating Sensitivity Values ................................................................................................................... 8
10.1.3.3 Sensitivity Combinations Screen............................................................................................................... 8
10.1.3.4 Calculation Screen .................................................................................................................................... 9
10.1.4 Gradient (Traverse)...................................................................................................................................... 17
10.1.5 Gradient (Traverse)-Modified Turner Equation ............................................................................................ 19
10.1.6 Erosional Velocity Calculations for Sand Laden Fluids ................................................................................ 20
10.1.7 VLP (Tubing) Curves – 3 Variables.............................................................................................................. 22
10.1.8 VLP (Tubing) Curves - 4 Variables .............................................................................................................. 26
10.1.9 Choke Performance ..................................................................................................................................... 29
10.1.10
Generate for GAP............................................................................................................................... 30
10.2
Calculation Menu – Rough Approximation Cases Only ............................................................................... 31
10.2.1 Bottom Hole Pressure from Wellhead Pressure........................................................................................... 31
10.2.1.1 Data Input................................................................................................................................................ 31
10.2.1.2 References.............................................................................................................................................. 33
10.3
10.3.1
10.3.2
10.3.3
10.3.4
10.3.5
10.3.6
11
Calculation Menu - Enthalpy Balance Temperature Model Only.................................................................. 34
Constrained System..................................................................................................................................... 35
Constrained VLP.......................................................................................................................................... 37
Unconstrained System ................................................................................................................................. 40
Unconstrained VLP (tubing curves) ............................................................................................................. 42
Unconstrained Gradient ............................................................................................................................... 44
Match Parameters........................................................................................................................................ 46
Design Menu .......................................................................................................................................................... 1
11.1
GAS LIFT DESIGN ........................................................................................................................................ 1
11.2
Gas Lift Design .............................................................................................................................................. 4
11.2.1 New Well........................................................................................................................................................ 4
11.2.1.1 Setting Up the Design Problem ................................................................................................................. 4
11.2.1.2 Gas Lift Valve Selection ............................................................................................................................ 9
11.2.1.3 Performing the Design (New Well) .......................................................................................................... 10
11.2.2 Existing Mandrels Design............................................................................................................................. 14
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11.2.2.1 Setting Up the Design Problem ............................................................................................................... 14
11.2.2.2 Defining the Depths of Existing Mandrels................................................................................................ 17
11.2.2.3 Gas Lift Valve Selection .......................................................................................................................... 18
11.2.2.4 Performing the Design (Existing Mandrels) ............................................................................................. 19
11.2.3 Notes on Gas Lift Design ............................................................................................................................. 21
11.2.3.1 Valve Spacing ......................................................................................................................................... 21
11.2.3.2 A Note on Designing with Tubing Sensitive Valves................................................................................. 22
11.2.3.3 Spacing Procedure for Tubing Sensitive Valves ..................................................................................... 22
11.2.3.4 A Note on Proportional Valves ................................................................................................................ 23
11.2.4 Gas Lift Valve Database .............................................................................................................................. 24
11.3
Gas Lift Adjustments .................................................................................................................................... 25
11.3.1 ESP Design.................................................................................................................................................. 29
11.3.2 ESP Calculate.............................................................................................................................................. 30
11.3.2.1 Checking Suitability of Separator Efficiency ............................................................................................ 31
11.3.3 ESP (Pump, Motor, Cable) Selection........................................................................................................... 32
11.3.3.1 Checking the Pump Design..................................................................................................................... 34
11.4
ESP Database ............................................................................................................................................. 35
11.4.1 Pump Database ........................................................................................................................................... 35
11.4.1.1 Adding a New Pump/Altering an Existing one/Importing Databases ....................................................... 36
11.4.2 Motor Database ........................................................................................................................................... 37
11.4.3 Cable Database ........................................................................................................................................... 38
11.5
HSP Design ................................................................................................................................................. 40
11.5.1 HSP Calculate.............................................................................................................................................. 41
11.5.1.1 HSP (Pump, Turbine) Selection .............................................................................................................. 42
11.5.1.2 Checking the Pump/Turbine Design........................................................................................................ 43
11.6
HSP Database ............................................................................................................................................. 45
11.6.1 HSP Pump Database ................................................................................................................................... 45
11.6.1.1 Adding a New Pump/Altering an Existing One/Importing Databases ...................................................... 46
11.6.2 Turbine Database......................................................................................................................................... 47
11.7
11.7.1
11.7.2
11.7.3
11.8
12
Progressive Cavity Pump Design................................................................................................................. 49
Setting Up the Pump Database in PROSPER ............................................................................................. 49
Database...................................................................................................................................................... 50
Typical Pump Curves ................................................................................................................................... 51
Coil Tubing Design....................................................................................................................................... 54
Output..................................................................................................................................................................... 1
12.1
Report ............................................................................................................................................................ 2
12.1.1 Setting Up the Reporting System................................................................................................................... 2
12.1.2 Reports .......................................................................................................................................................... 2
12.2
Export........................................................................................................................................................... 15
12.2.1 Export Setup ................................................................................................................................................ 15
12.3
Plot............................................................................................................................................................... 17
12.3.1 Plot Command Summary ............................................................................................................................. 17
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13
TABLE OF CONTENTS
Units ....................................................................................................................................................................... 1
13.1
13.1.1
13.1.2
13.1.3
13.1.4
Units Summary............................................................................................................................................... 1
Unit Systems.................................................................................................................................................. 2
Changing Unit Systems for some variables ................................................................................................... 3
Changing the Units......................................................................................................................................... 3
Validation Limits............................................................................................................................................. 4
13.2
Units Detailed................................................................................................................................................. 5
13.3
Units Reset .................................................................................................................................................... 5
14
Help................................................................................................................................................................ 1
14.1
Finding Information in Help ....................................................................................................................... 1
14.1.1 Use the Search feature in Help ...................................................................................................................... 1
14.1.2 Use the Help Index......................................................................................................................................... 1
14.1.3 Context Sensitive Help................................................................................................................................... 1
14.2
14.2.1
14.2.2
14.2.3
14.2.4
Accessing Help.......................................................................................................................................... 2
Help Through the Menu ................................................................................................................................. 2
Getting Help Using the Mouse ....................................................................................................................... 2
Getting Help Using the Keyboard................................................................................................................... 2
To Minimise Help ........................................................................................................................................... 2
14.3
What’s New ............................................................................................................................................... 2
14.4
Worked Examples ..................................................................................................................................... 2
14.5
Flow Correlations ...................................................................................................................................... 2
14.6
Help About PROSPER .............................................................................................................................. 3
PETROLEUM EXPERTS LTD
TABLE OF CONTENTS 10 - 12
Appendix A
Worked Examples............................................................................................................................ 1
A1
Example 1 – Naturally Flowing Oil Well ......................................................................................................... 1
A1.1 Defining the System....................................................................................................................................... 1
A1.2 Entering and Matching PVT Data................................................................................................................... 2
A1.3 Entering the IPR data..................................................................................................................................... 5
A1.4 Entering the Equipment data.......................................................................................................................... 6
A1.5 Matching Menu .............................................................................................................................................. 8
A1.5.1 Correlation Comparison ............................................................................................................................ 8
A1.5.2 VLP Matching............................................................................................................................................ 9
A1.5.3 IPR Matching........................................................................................................................................... 10
A1.5.4 Checking the Model for High Rate Test................................................................................................... 11
A1.6 Performing a Systems Analysis ................................................................................................................... 13
A1.7 Generating VLP Lift Tables for Simulators................................................................................................... 16
A2
A2.1
A2.2
A2.3
Example 2 - Gas Lift Design ........................................................................................................................ 17
Setting up the Gas lift valve database.......................................................................................................... 18
Setting up the Design Parameters ............................................................................................................... 19
Calculating Sensitivities ............................................................................................................................... 21
A3
A3.1
A3.2
Example 3 - Well and Flow line Modelling.................................................................................................... 23
Calculating the System Solution .................................................................................................................. 24
Plotting the Temperature Profile .................................................................................................................. 26
A4
A4.1
A4.2
A4.3
A4.4
Example 4 - Temperature Prediction ........................................................................................................... 27
Defining the System..................................................................................................................................... 27
Defining the Equipment Data ....................................................................................................................... 28
Calculation Section ...................................................................................................................................... 30
Generating a Temperature Gradient Plot..................................................................................................... 31
A5
A5.1
A5.2
A5.3
Example 5 - ESP Lifted Well ........................................................................................................................ 33
Defining the System..................................................................................................................................... 33
Designing the pump ..................................................................................................................................... 35
Checking the design for different conditions. ............................................................................................... 37
A6
A6.1
A6.2
A6.3
Example 6 - HSP Lifted Well........................................................................................................................ 39
Defining the System..................................................................................................................................... 39
Designing The Pump.................................................................................................................................... 40
Checking the Design for Changed Conditions ............................................................................................. 42
A7
Example 7 - Retrograde Condensate Well................................................................................................... 44
A7.1 Entering EOS PVT ....................................................................................................................................... 44
A7.2 Matching Menu / Correlation Selection ........................................................................................................ 47
A7.3 BLACK OIL Condensate PVT ...................................................................................................................... 49
A7.3.1 Selecting the Options .............................................................................................................................. 49
A7.3.2 Matching/ Correlation Selection .............................................................................................................. 50
A8
Example 8 - Gravel Packed Gas Well.......................................................................................................... 52
A8.1 Defining the System..................................................................................................................................... 52
A8.1.1 Options Menu.......................................................................................................................................... 52
A8.1.2 PVT menu ............................................................................................................................................... 52
A8.1.3 System Menu (Equip & Inflow) ................................................................................................................ 53
A8.2 Sensitivity Calculation Menu ........................................................................................................................ 55
A8.2.1 IPR Liquid Sensitivity............................................................................................................................... 58
A9
A9.1
Example 9 - Horizontal Well - Friction dP..................................................................................................... 59
Setting up the example ................................................................................................................................ 59
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PROSPER MANUAL
11 - 12
TABLE OF CONTENTS
A9.1.1 IPR Data Input......................................................................................................................................... 59
A9.2 Coning Calculations for Horizontal Wells ..................................................................................................... 60
A10
Example 10 - Multi-Layer dP Pressure Loss................................................................................................ 63
A10.1 Setting up the example ................................................................................................................................ 63
A10.2 IPR Data Input ............................................................................................................................................. 63
A10.2.1 STEP1: Defining the top of the multi-layer system .................................................................................. 64
A10.2.2 STEP2: Defining the to Top Producing layer........................................................................................... 64
A10.2.3 STEP3: Defining the non producing zone ............................................................................................... 65
A10.2.4 STEP4: Defining the to Bottom Producing layer...................................................................................... 65
A11
Example 11 – Multilateral well...................................................................................................................... 67
A11.1 Introduction .................................................................................................................................................. 67
A11.2 How to set up the model .............................................................................................................................. 68
A12
A12.1
A12.2
A12.3
A12.4
A12.5
Example 12 – Modelling of a smart well completion using Multilateral option in PROSPER........................ 88
Statement of the problem............................................................................................................................. 88
Defining the System..................................................................................................................................... 89
Entering PVT Data ....................................................................................................................................... 90
Entering the Equipment data........................................................................................................................ 91
Modelling the smart well completion (IPR)................................................................................................... 93
A13
A13.1
A13.2
A13.3
A13.4
Example 13 - Gas Injector with down-hole chokes using Multi-lateral model............................................. 115
Defining the System Set Up ....................................................................................................................... 116
Entering the PVT data................................................................................................................................ 117
Entering the Equipment data...................................................................................................................... 118
Defining the IPR data (Inflow) .................................................................................................................... 120
A14
Example Using Multi-lateral model and PCP ............................................................................................. 144
A15
Files location .............................................................................................................................................. 164
Appendix B
References ...................................................................................................................................... 1
B1
PVT Calculations............................................................................................................................................ 1
B2
IPR Calculations............................................................................................................................................. 2
B3
Multiphase Flow Calculations......................................................................................................................... 4
B4
Temperature Calculations .............................................................................................................................. 5
Appendix C
Equations......................................................................................................................................... 1
C1
C1.1
C1.2
C1.3
Black Oil Model for Condensate..................................................................................................................... 1
Mass Balance Calculations ............................................................................................................................ 1
Using the mass balance results to define Condensate Model ....................................................................... 4
Estimation of CGRmin ...................................................................................................................................... 6
C2
Multiphase Pseudo Pressure ......................................................................................................................... 7
C3
Temperature Models ...................................................................................................................................... 9
C4
Default Thermal Properties Database.......................................................................................................... 13
C4.1 Dry Rock Properties ..................................................................................................................................... 13
C4.2 Rock In Situ Fluids ....................................................................................................................................... 13
PETROLEUM EXPERTS LTD
TABLE OF CONTENTS 12 - 12
C4.3 Downhole Equipment ................................................................................................................................... 13
C5
Rough Approximation Temperature Model .................................................................................................. 14
C6
Choke Calculation........................................................................................................................................ 15
C7
Multi-Phase Flow Correlations ..................................................................................................................... 15
Appendix D
Dietz Shape Factors ........................................................................................................................ 1
Appendix E
File Formats..................................................................................................................................... 1
E1
Introduction .................................................................................................................................................... 1
E2
External PVT Tables ...................................................................................................................................... 1
E3
Lift Curves...................................................................................................................................................... 3
E4
IPR ................................................................................................................................................................. 4
E5
ESP PUMPS .................................................................................................................................................. 4
E6
ESP MOTORS ............................................................................................................................................... 5
E7
ESP CABLES................................................................................................................................................. 6
E8
HSP PUMPS.................................................................................................................................................. 6
E9
HSP TURBINES............................................................................................................................................. 7
SEPTEMBER 2003
PROSPER MANUAL
1 Introduction
Welcome to PROSPER, Petroleum Experts Limited's advanced PROduction and Systems
PERformance analysis software. PROSPER can assist the production or reservoir engineer
to predict tubing and pipeline hydraulics and temperatures with accuracy and speed.
PROSPER's powerful sensitivity calculation features enable existing designs to be
optimised and the effects of future changes in system parameters to be assessed.
By separately modelling each component of the producing well system, then allowing the
user to verify each model subsystem by performance matching, PROSPER ensures that the
calculations are as accurate as possible. Once a system model has been tuned to real
field data, PROSPER can be confidently used to model the well in different scenarios and to
make forward predictions of reservoir pressure based on surface production data.
1.1
Using PROSPER
PROSPER is a fundamental element in the Integrated Production Model (IPM) as defined
by Petroleum Experts, linking to GAP, the production network optimisation
program for gathering system modelling and MBAL, the reservoir engineering
and modelling tool, for making fully integrated total system modelling and
production forecasting.
PROSPER has a PVT section which can generate fluid properties using standard
correlations and allows them to be modified to better fit measured lab data.
PROSPER allows detailed PVT data in the form of tables to be imported for use
in the calculations. A third option is to use the Equation of State method. This
option also allows the user to enter the equation of state model parameters and
uses the standard Peng-Robinson EOS model to generate properties given a
multi-stage separator scheme. With this option the users can also import all
PVT data in the form of tables, which could have been generated using their
own proprietary EOS models.
PROSPER can be used to model reservoir inflow performance (IPR) for single, multilayer, or
multilateral wells with complex and highly deviated completions, optimising all
aspects of a completion design including perforation details and gravel packing.
PROSPER can be used to accurately predict both pressure and temperature profiles in
producing wells and along surface flow lines.
PROSPER sensitivity calculations easily allow the engineer to model and optimise tubing,
choke and surface flow line performance.
PROSPER can be used to design, optimise and troubleshoot gas lifted, ESP equipped or
HSP (hydraulic pump) equipped wells.
PROSPER’s choke calculator can be used to predict flow rates given the choke size, or the
choke size for a specified production rate and of course, the pressure drop
across a known choke at a specified rate.
PROSPER uses multiphase flow correlations which have can be adjusted to match
measured field data to generate vertical lift performance curves (VLP) for use in
simulators and network models.
2 - 10
CHAPTER 1 - INTRODUCTION
PROSPER can utilise externally programmed dynamic link libraries (DLL) for multiphase
flow correlations, Equation of State (EOS) PVT calculations, choke calculations
and Inflow (IPR) models.
PROSPER can be used in a matching or predictive mode. Matching of real data is available
in the PVT, IPR, Gradient matching and VLP matching sections.
•
•
In matching mode, real data can be entered and matched using non-linear
regression methods to create custom correlations that fit the input data.
In predictive mode, the correlations created can be used to make estimates
of future well performance.
PROSPER can be used to model complex (topographically) and extensive (in length)
surface pipelines. PROSPER can also perform some complex steady state slug
analysis taking into account slug build up and decay due to pipeline topography,
giving an indication of expected slug length and frequency.
PROSPER accepts Black Oil PVT tables directly from Petroleum Experts’ PVTP
thermodynamics analysis program. EOS fluid characterisation parameters can
also be directly imported.
PROSPER has a flexible units system. Data may be input using one set of units and output
using a second set of units. Validation limits and display resolution can be
independently set for each variable type.
PROSPER has the utility for flagging of potential hydrate formation, if the user chooses this
in the options. The additional input required for this calculation is the hydration
formation tables as a part of PVT.
PROSPER can model the following types of problems:
Prediction Type:
•
•
•
Pressure Only
Pressure and Temperature Offshore
Pressure and Temperature on Land
Temperature Model:
• Enthalpy Balance
• Rough Approximation
• Improved Approximation
Fluid Type:
• Oil and Water (Black oil or Equation of State PVT)
• Dry and Wet Gas (Black oil or Equation of State PVT)
• Retrograde Condensate (Black Oil PVT)
• Retrograde Condensate (Equation of State PVT)
• Emulsion viscosity can be optionally applied for any combination of inflow,
tubing and ESP’s or HSP’s.
Well Flow Configuration:
• Tubing or Annular flow or Tubing + Annular flow
• Producer or Injector
Lift Method:
• Naturally flowing well
PETROLEUM EXPERTS LTD
Chapter 1
•
•
•
•
•
3-10
Gas lifted well
Electric submersible pump (ESP)
Hydraulic drive downhole pump (HSP)
Progressive Cavity Pumps
Gas Lift with Coil Tubing
Completion:
• Cased Hole
• Open Hole
• Gravel Pack
Separation Mode:
• Single-Stage
• Two-Stage
• Multi-Stage (Compositional model only)
Reservoir:
• Single Well
• Multi-lateral Well in a Multi-layered Reservoir
• Gas Coning (Rate dependent GOR calculator)
AUGUST 2003
PROSPER MANUAL
4 - 10
1.2
CHAPTER 1 - INTRODUCTION
PROSPER and Systems Analysis
PROSPER can help petroleum producers maximise their production earnings by providing
the means to critically analyse the performance of each producing well. Each well system
component that contributes to overall performance is separately modelled: Inflow
performance, pressure drop in the tubing and pressure losses in the surface gathering
system are individually calculated and performance matched where possible.
Well potential and producing pressure losses are both dependent on fluid (PVT) properties.
The accuracy of systems analysis calculations is therefore dependent on the accuracy of
the fluid properties model (i.e. PVT). The pressure drop in a pipeline or wellbore is the
summation of 3 components:
• Gravity head
• Friction loss
• Acceleration
i.e.
∆ptotal = ∆pgravity + ∆p friction + ∆pacceleration
The gravity component is due to the density of the fluid mixture at each point in the system
and is a complex function of the relative velocity of the phases present. PROSPER makes a
flash computation at each calculation step to determine the proportion of oil, water and gas
present. The no-slip density is then calculated using the proportions of each phase and
the predicted density at each pressure and temperature step.
Industry standard 2-phase correlations are then applied to determine the increase in
apparent fluid density due to the higher vertical velocity of gas compared to oil and water
(slippage). The gravity head loss is proportional to the fluid density corrected for slip. The
slip correction to be applied depends on the flow regime, fluid velocity etc. The need for an
accurate PVT description for predicting the gravity head loss is clear.
Friction losses are controlled by fluid viscosity and geometric factors (pipe diameter and
roughness). In the majority of oilfield applications, (i.e. large elevation difference between
inlet and outlet with liquids present) the gravitational component normally accounts for
around 90% of the overall head loss. Therefore, the total pressure drop function is not
particularly sensitive to the value of the friction loss coefficient.
The acceleration component is usually small except in systems involving significant fluid
expansion. However, it is accounted for in all PROSPER calculations.
Historically, systems analysis software has lumped all flowing pressure loss terms together
and allowed the user to match real data by adjusting the roughness coefficient of the
friction loss term. This will certainly achieve a match for a particular rate, but cannot be
expected to achieve a match over a significant range of rates due to the different
dependencies of the gravity and friction loss terms on liquid velocity.
PROSPER's approach is to first construct a robust PVT model for the reservoir fluid.
Entering laboratory PVT data and adjusting the correlation model until it fits the measured
data improve the accuracy of forward prediction.
Constructing an accurate PVT model confines the uncertainty in the gravity loss term to the
slip correction only.
In the VLP matching phase, PROSPER divides the total pressure loss into friction and
gravity components and uses a non-linear regression technique to separately optimise the
value of each component. Not only does the matching process result in a more accurate
model, it will quickly highlight inconsistencies in either the PVT or equipment description.
PETROLEUM EXPERTS LTD
Chapter 1
5-10
Provided sufficiently accurate field data is available, robust PVT, IPR and VLP models can
be prepared by performance matching. Each model component is separately validated,
therefore dependency on other components of the well model is eliminated. Trouble
shooting changes in production rates is simplified as the matching process can eliminate
many variables that could otherwise confuse the situation.
1.2.1
A Note About PROSPER
PROSPER can predict either Pressure Only or Pressure and Temperature. The
Pressure Only option makes PROSPER a "Systems Analysis" package in the traditional
sense. In Pressure Only mode, the well temperature profile must be input by the user.
Temperature data is normally recorded whenever a pressure survey is made, as the
temperature is required to correct the downhole pressure readings. This type of calculation
is fast and sufficiently accurate for the majority of pressure loss calculation purposes.
The Pressure and Temperature calculation option will generate both temperature and
pressure profiles. Three temperature models are provided. The Rough Approximation
model utilises a user-input overall heat transfer coefficient. It determines the steady state
temperature profile from the mass flow rates of oil, water and gas before commencing the
pressure loss calculations. This method runs quickly, but unless calibrated using
measured temperature data, it is not accurate. The Improved Approximation model
extends the Rough Approximation model by allowing the variation of heat transfer
coefficient by depth and pipe section and the addition of a temperature gradient in the sea.
The Enthalpy Balance model calculates the heat transfer coefficients at each calculation
step by considering heat flow and enthalpy changes. The Joule Thomson effect,
convection and radiation are modelled. These calculations require considerably more input
data than for pressure only calculations and must commence from a known temperature
and pressure (the sand face for producers, or wellhead for injectors). Computation times
are longer than for the Rough Approximation option, but this method is predictive and
gives accurate results over a wide range of conditions. The Enthalpy Balance model is
completely transient and can be used to study temperature changes over time.
Temperature prediction is useful for generating temperature profiles in:
•
•
•
•
long pipelines transporting Retrograde Condensate.
subsea wells with long flowlines
high pressure/temperature exploration wells
predicting temperature/pressure profiles to help predict wax/hydrate deposits
The production riser is properly accounted for by PROSPER. The user-input riser geometry
determines the heat loss coefficients calculated by the program between the seabed and
wellhead.
PROSPER is also able to predict condensate liquid drop out using either black oil or
compositional models.
PROSPER uses a "Smart Menu" system. Only data relevant to a particular problem need
be entered.
The flow chart shown over leaf gives an outline of the calculation steps required to carry
out a simple systems analysis using PROSPER.
AUGUST 2003
PROSPER MANUAL
6 - 10
CHAPTER 1 - INTRODUCTION
Chapter 1
1.3
7-10
Examples
To help illustrate the power of PROSPER, examples are provided with the program. We
suggest you run through them to become familiar with the program and its various options.
These examples are in ~\samples\PROSPER directory. The location of this directory
depends on where the program has been installed.
1.3.1
Example 1 – Naturally Flowing Oil Well
File: Oilwell.out
The objectives of this example are to:
• Show how removing skin can increase production.
• Show how increasing the tubing size can increase production.
• Generate lift curves for a reservoir simulator.
This example demonstrates how to:
• Match the PVT correlations to real data.
• Match the multiphase flow correlations to real data using VLP matching.
• Use IPR matching to determine reservoir pressure.
• Run a system analysis with sensitivities.
• Run a pressure versus depth gradient calculation.
• Generate vertical lift tables for a reservoir simulator.
1.3.2
Example 2 – Gas Lift Design
File: Gaslift.out
The objectives of this example are to:
• Find the maximum production rate achievable using gas lift.
• Determine the optimum lift gas injection rate and depth.
• Design the operating and unloading valves.
This example demonstrates how to:
• Setup the gas lift design parameters.
• Calculate the design production and gas injection rates.
• Space out the valves.
• Determine the valve trim sizes and dome pressures.
• Calculate production sensitivities using the gas lift design.
1.3.3
Example 3 – Well and Flowline Modelling
File: flowline.out
The objectives of this example are to:
• Model a flowline using PROSPER.
• Apply the Rough Approximation temperature model.
• Examine the effect of the flowline on production rate sensitivities.
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8 - 10
CHAPTER 1 - INTRODUCTION
1.3.4
Example 4 – Temperature Prediction
File: enthalpy.out
This test example shows how to use the Enthalpy Balance temperature model to predict
the wellhead flowing temperature (WHFT) of a high pressure / high temperature oil well.
1.3.5
Example 5 – ESP Lifted Well
File: espwell.out
The objectives of this example are to:
• Determine the pump duty required to meet a specified offtake rate
• Select a suitable combination of pump, motor and cable for the service
• Determine the maximum water cut at which the pump can still operate with the
design offtake rate.
This example demonstrates how to:
• Use existing PVT and VLP data as the basis of a new analysis
• Calculate pump intake and outlet pressures
• Design an ESP system
• Evaluate pump operating point sensitivities
• Calculate a flowing gradient for an ESP equipped well.
1.3.6
Example 6 – HSP Lifted Well
File: hspwell.out
The objectives of this example are to:
•
Select a suitable combination of pump, turbine and cable for the service
This example demonstrates how to:
•
•
•
•
Use existing PVT and VLP data as the basis of a new analysis
Calculate pump intake and outlet pressures
Design an HSP system
Evaluate pump operating point sensitivities
PETROLEUM EXPERTS LTD
Chapter 1
1.3.7
9-10
Example 7 – Retrograde Condensate Well
File: condex.out, condex2.out, condex3.out
The objectives of this example are to:
• Calculate condensate PVT using convergence pressure, equation of state (EOS)
and black oil methods
• Compare the production rate results obtained from each method
• Calculate and compare pressure traverses from each method
This example demonstrates how to:
• Enter reservoir fluid composition data and calculate phase behaviour
• Match laboratory and predicted PVT properties
1.3.8
Example 8 – Gravel Packed well
File: gravel.out
The objectives of this example are to:
• Design a gravel packed completion for a high rate gas well
• Determine the allowable offtake for a specified drawdown on the formation
This example demonstrates how to:
• Enter the gravel pack and completion parameters
• Calculate sensitivities on gravel pack and perforation variables
• Calculate the pressure loss across the completion and thereby determine the
drawdown at the sandface.
1.3.9
Example 9 – Horizontal Well – Friction dP
File: hwell.out
The example shows how to set up the input data for a Horizontal well - Friction dP IPR
model. It is based on the OILWELL example file. Note that the reservoir permeability must
be increased from 50 in the base example to 500 milli-darcies in order to see the friction
pressures drop along the wellbore.
1.3.10
Example 10 – Multi-Layer dP Pressure Loss
File: mlayer.out
The example shows how to set up the input data for a Multi-Layer IPR model. It is based
on the OILWELL example file.
AUGUST 2003
PROSPER MANUAL
10 - 10 CHAPTER 1 - INTRODUCTION
1.3.11
Example 11 – Multi-lateral well
File: multilat1.out
The example shows how to set up the input data for an ordinary multilateral well.
1.3.12
Example 12 – Modelling of a smart well completion using
multilateral option in PROSPER
File: multilat2.out
The objectives of this example are to:
• Show how a complex smart well completion can be modelled by using the
multilateral option in PROSPER
• Show how different tubing sizes can affect the IPR curve
1.3.13
Example 13 – Gas injector with downhole chokes using
multilateral model
File: multilat3.out
The objectives of this example are to:
• Go through the step-by-step procedure for defining a multi-lateral gas injector.
• Determine the gas injection rate into the reservoirs for a series of wellhead
pressures.
• See the effect of varying the choke opening on the injectivity.
This example demonstrates how to:
• Build multi-lateral gas injectors in PROSPER.
• How to perform sensitivity calculation in multilateral wells.
1.3.14
Example 14 – Multilateral model including PCP
File: multilat-PCP.out
The objectives of this example are to:
• Go through the step-by-step procedure for defining a multi-lateral well model.
• Determine if the well can flow on its own.
• Considering multilateral model set a PCP pump and determine the pump
requirements to keep the well flowing.
This example demonstrates how to:
• Build multi-lateral well model in PROSPER.
• How to set design the pump requirements.
PETROLEUM EXPERTS LTD
2 Installation
This chapter establishes the minimum recommended hardware necessary to run
PROSPER and provides instructions for installing the program on your computer. The
guide assumes you have a working knowledge of Windows terms and procedures. If you
are unfamiliar with the Windows operating system, we recommend you read the relevant
sections in the Microsoft Windows User's Guide to learn more about Windows operations.
2.1
System Requirements
Before you proceed with PROSPER, make sure Microsoft Windows has been installed on
your computer. For information on installing Windows, please refer to your Windows
Installation Guide or contact a member of your data processing and support department.
If you intend connecting a printer to your PC, ensure that the required printer drivers and
fonts have been installed. PROSPER supports any certified device drivers shipped with
Windows. A list of software and hardware devices supported by Microsoft is included with
your Windows documentation. The following is a list of the equipment needed to effectively
run the program.
2.1.1
Hardware
The following items represent a minimum requirement only. For optimum performance,
additional memory and a high performance processor is recommended.
•
IBM PC or fully compatible computer equipped with a Pentium class or better
processor
•
A CD-ROM drive.
•
A minimum 32 Megabytes of RAM - this is the absolute minimum. 128 MB or
more is required for links with GAP or other applications.
•
Hard disk with at least 45 Megabytes of free disk space
•
VGA or better monitor
•
Windows compatible mouse
•
Any printer that is supported by Windows
•
A Petroleum Experts Limited authorised software protection key or HardLock
software
While PROSPER will run under this minimum configuration, a recommended entry level
system is a 300 MHz Pentium II processor with 128 MB or more of memory.
2-2
Chapter 2 - Installation and Windows Basics
2.1.2
Software
PROSPER runs under Windows 98, NT, 2000, ME and requires:
•
•
At least 32 Megabytes of memory and a configured swap file.
Petroleum Experts authorised software protection key or a Network Protection
System (HardLock). Key drivers are required for all operating systems.
The software protection key is connected to your PC via a parallel port - usually the printer
port. If you use protection keys for other software, we do not recommend stacking them
together. Possible incompatibilities between keys may cause read/write or access errors
with some keys.
PROSPER is compatible with network software. It can be installed and accessed from a
file server and executed on a local PC, provided it is fitted with an appropriate software
protection key. Alternatively, Petroleum Experts’ Hardlock network licence manager software
can be installed on the file server to replace the keys. Details vary from network to
network; please contact Petroleum Experts for information specific to your system.
2.1.3
Upgrading From a Previous Version
For convenience in running linked models, Petroleum Experts software products now installs by
default into the common directory \Program Files\Petroleum Experts. To avoid the
potential for conflicts between program and DLL versions, it is recommended to install
GAP, MBAL and PROSPER in the same directory.
If you wish to keep an original version of the program, back it up into another directory
before installing the upgrade. Saving 'old' versions of the program on your hard disk is not
recommended, as it takes up valuable disk space and potentially leads to file/program
incompatibility. Backup your old versions onto floppy disks before installing a newer
version.
Â
All program upgrades are backward compatible. This ensures that data files
created with earlier versions of the program can still be read by later program
versions. However, if you save a data file with the new version, that file can no
longer be opened by earlier versions! As with all new software installations,
always back up your PROSPER files.
PETROLEUM EXPERTS LTD
Chapter 2
2.2
2-3
Installing PROSPER
Before installing the program, first determine:
•
The drive where the program will be installed
•
The amount of space available on the selected drive
•
If installing the program on a network, make certain you have the appropriate
access rights for creating directories and files on the selected volume.
2.2.1
What Setup Does
The installation procedure:
Â
•
Creates a program directory on your hard disk.
•
Creates a sample files sub directory on your hard disk.
•
Unpacks the program and related files to the selected drive and directory.
•
Creates a program initialisation file PROSPER.INI in your Windows directory.
•
Creates a new Windows program group and icon for both PROSPER and for
associated utilities subfolder.
To avoid potential system resources conflicts, please shut down other
applications before running SETUP. Some anti-Virus programs can interfere
with the installation process and may need to be shut down.
Boot up your computer and start Windows. From the Start Menu, click Run, then enter:
D:\SETUP
Assuming your CD-ROM, drive letter is D.
A program installation screen will appear. You will be prompted to enter a drive and
directory path where the program will be installed. The default drive and path are:
C:\Program Files\ Petroleum Experts\IPMX.Y
(where X.Y is the IPM version)
This default may be changed to the drive and path of your choosing (e.g. C:\PE). Click in
‘Next’ to proceed. The rest of the setup procedure should be self-explanatory.
The setup procedure creates the specified directory on your hard disk and copies all
appropriate files on the distribution media to the selected directory. It also creates a sample
files sub-directory within the directory path. This directory contains the test samples
referred to in this user guide.
As part of the installation procedure you will also be prompted for the name of the program
group into which you wish the PROSPER icon to be placed. By default the destination is
the ‘Petroleum Experts IPMX.Y ’ program group (X.Y refers to the IPM version) but this
can be changed to any existing group or to any new group, which you would like to be
created. This results in the PROSPER program icon, the icon for utilities sub-group. Within
the utilities group there are icons for REMOTE utility, the online manuals, latest acrobat
reader installation and internet link to Petroleum Experts website and Superpro bit lock driver.
You will be informed when the installation process is complete. Remove the CD-ROM from
its drive and store it away in a safe place.
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2.2.2
Chapter 2 - Installation and Windows Basics
Configuration file (PROSPER.INI)
The file PROSPER.INI (which stores the current configuration details such as last file
name, screen colours etc.) will be created in your Windows sub-directory. An entry will be
also made in your WIN.INI file, which tells Windows where to look for PROSPER.INI as
follows:
[Petroleum Experts]
INIPATH=PROSPER.INI
2.2.3
Key drivers for Windows 98, NT, 2000, ME
The Superpro bit lock driver will be installed under utilities sub-group. This program MUST
be run once the installation program has finished, if no drivers are already installed (i.e. if
no Petroleum Experts products have previously been installed on the machine). It is only
necessary to run it once, just after installation. If you do not run this program you will not be
able to see the key at all under Windows NT/2000, while under Windows 98 you will be
able to see the key but there is a good possibility that the key will be wiped at some point in
the future when you try to update an authorisation code. When the driver program runs up,
simply select the Install option from the Functions menu and follow instructions. There
should be no need to configure the drivers as the parallel port will be detected
automatically.
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Accessing PROSPER
To access the program, select the PROSPER icon and press ↵, or double-click the
program icon. The installation process will normally create the icon. If for any reason you
need to manually create it, refer to the following section.
2.3.1
Connecting the software protection key
The software protection key must be attached to the PARALLEL printer port. DO NOT
connect the key to a serial port, as this can damage the key or your PC. If you are using
protection keys 718ocR66/n,hR.t
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Chapter 2 - Installation and Windows Basics
2.4
REMOTE Software Key Utility
All Petroleum Experts software requires a software protection device to allow it to run.
REMOTE.EXE is a utility program provided with our software that enables you to access
the software protection key used with Petroleum Experts applications. REMOTE is included with
each software distribution and is installed simultaneously with the application program.
REMOTE allows you to view the key number, the enabled program options and license
expiry date.
This utility is also used to enter the authorisation codes that will update or activate the
software key where necessary. For reasons of security, Petroleum Experts normally sends an
inactive software device with the application program. The codes needed to activate or
update the software key are sent separately by facsimile or mail.
2.4.1
Entering the Authorisation Code
You enter user authorisation codes only if:
•
•
•
The software protection key you have received is inactive,
Access period for the program has expired, or
You have acquired new program options
To enter the authorisation codes, double-click the REMOTE utility icon or select the
REMOTE program from the Programs menu. The installation process will normally create
the icon in the same group as PROSPER. If the icon does not already exist on the
Windows desktop, please follow the steps described above for creating the PROSPER
icon. Enter the following:
Description :
Command Line:
REMOTE
C:\ Program Files \ Petroleum Experts \ IPMX.Y \
REMOTE.EXE
Enter the authorisation code by taking the following steps:
•
Double click on the REMOTE icon. The following screen will appear:
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Figure 2-1
REMOTE Key Example
•
•
If your software protection key is already active, a list of authorised programs and
the number of licences associated with that product will appear in the window.
Any options associated with a particular product can be seen in the list too. You
may quit the REMOTE Utility program. No authorisation code is required.
If no program is enabled for the key, select the 'Update’ command button. A
screen of zero digit codes will appear. Enter the codes you have received from
Petroleum Experts from left to right beginning with the top row. Press Continue to
activate the codes. You will be returned to the REMOTE Utility screen. Press
Cancel to quit the code update.
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Chapter 2 - Installation and Windows Basics
Figure 2-2
Authorisation Codes
Screen
2.4.2
Updating the Software Protection Key
Access to the software automatically ceases when the license expiry date has elapsed.
You are however, reminded several days in advance, which gives you sufficient time to
contact Petroleum Experts to obtain update codes. This occurs when either:
•
The software license trial period has ended.
•
The annual software maintenance fee is due.
Software protection keys also need updating when you acquire new Petroleum Experts software
packages. The procedure for updating the software key is the same as described above.
When the appropriate screen appears, enter the codes provided - from left to right
beginning with the top row. Press Continue to activate the codes, or Cancel to quit the
update. To view the expiry date for any of the enabled programs, click on the software title.
When you receive new codes, always update every key that belongs to your company.
Subsequent updates may fail if all previously issued codes have not been properly entered
into the key.
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PROSPER Sample Files
2.5
If you want to sample the PROSPER features quickly, test examples are provided for you.
Following the instructions in Appendix A will show you how to model some commonly
encountered problems.
2.6
Program Check List
To ensure trouble free operation of the software, please ensure that:
•
You have sufficient disk space. A minimum of 45 MB is required for the
program alone and whatever space is required for your data and sample files.
•
The software protection key is firmly in place in the parallel port thus ensuring
good connection to your computer. Do not connect the key to the serial port,
as this can damage the key or your PC. If the dongle is loose, the program will
not be able to access the key to start the program.
•
The printer cable is firmly attached to the software key. Your printer must be
turned ON and put on-line or the key will not function.
•
The key drivers have been installed if running under Windows 98 / ME or
Windows NT / 2000.
•
The PC system date is set correctly to the current date. The key records the
date that the program and software device were last accessed. If the PC date
is set to some time before or after the date recorded on the key, the
discrepancy will be detected and user authorisation terminated. If running on a
network, ensure that your PC clock is synchronised with network time.
•
You back up your files on a weekly basis. Files not used on a regular basis
should be removed and stored on diskette. Diskettes should be clearly labelled
with the well name or filename and date of backup.
•
Basic disk management is performed on a regular basis with disk utility
programs. This could help detect potential problems with your hard disk before
it is too late to avoid file corruption. Compression of old data files using a utility
such as WINZIP may be useful as an archiving tool. However, they will not
save much space as all PROSPER data files are themselves compressed to
save space.
2.6.1
Smart Menus
PROSPER uses a "Smart Menu" technique that facilitates the process of data entry by
limiting the screens, input fields and item selections to those relevant to your particular
application. Smart Menus have the advantage that only the required fields are displayed,
making it easy and efficient for you to enter data.
As the sequence of input screens required is determined by the application parameters you
choose, your selections should be made with care. Selections may be changed at any
time, however you will need to remember that new choices will in many cases require
further data to be supplied. For example, changing from Pressure Only to Pressure and
Temperature requires the equipment screen to be updated.
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3 File Management
This section describes the menus, options and procedures used in PROSPER to create new
files and open or save existing files. The Units system and how to define printer settings
are also outlined. The menus described in this section are the PROSPER File menu and
Units menu.
The File menu provides additional options such as defining the default data directory, as
well as the facility to establish access links to other programs running under Windows.
PROSPER will (optionally) open the last file accessed when it starts. PROSPER also
displays a file status screen that shows the application options selected in summary format:
input PVTP and IPR data, the equipment type summary and the analysis output.
To protect your work, you should save your data on a regular basis. This simple procedure
could potentially prevent hours of input and analysis being lost.
3.1 PROSPER Files
PROSPER uses a flexible file structure that enables data to be easily exchanged between
files and other application programs. In PROSPER information is grouped into the following
categories:
• PVTP
• Analysis
• System
• Output
and saved into the following types of data file:
3.1.1 PVT Data (*.PVT)
File containing the well fluid data, PVTP match data and any PVTP tables entered under
the PVTP menu. You can save PVTP files separately under different names, and use
them with other input, analysis and output files in PROSPER. This feature is useful when
analysing a number of wells from the same producing pool.
3.1.2 Input Data (*.SIN)
SIN files contain the options selected under the Options menu, in addition to the well IPR
and equipment data entered under the System menu. When you open and save an input
file, the program automatically opens and saves a .PVTP file with the same name.
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3.1.3 Analysis Data (*.ANL)
This file contains the analyses and sensitivity input data for the calculations selected under
the Analysis menu. When you open and save an analysis file, the program automatically
opens and saves a .PVT & .SIN file with the same name. GAP and PRODMAN manipulate
.ANL files to batch calculate well lift curves.
3.1.4 Output Data (*.OUT)
This file contains the results of the calculations. When you open and save an output file,
the program automatically opens and saves a .PVT, .SIN & .ANL file of the same name.
PROSPER files are ranked by their order of input, which essentially reflects the way data
should be entered into the program, that is from the LEFT to the RIGHT of the PROSPER
menu. You will note that the order of files also corresponds to options on the menu bar as
you move through the program.
The file hierarchy does not prevent you from creating and combining any number of input
and output data files. Until you become familiar with the program, we recommend that you
always work with *.OUT files. This can avoid confusion as the program will automatically
open and save the required data files to run a complete analysis cycle.
More experienced users can take advantage of the flexible file structure to combine the
data files from different wells. This "sharing" of data is useful in areas where wells have
similar fluid properties or reservoir IPR's. If disk space is a concern, the data contained in
a .ANL file together with its complementary .PVT and .SIN files can be used to re-create a
given set of calculation outputs, therefore avoiding the need to always save large .OUT
files on disk.
For example, if you wanted to run an analysis with the PVTP data of Well 1, the input data
(*.SIN) data of Well 2, and the analysis data of Well 3, take the following steps:
•
Open Well 3.ANL
•
Open Well 2.SIN
•
Recall Well 1.PVTP under the PVTP menu.
•
Under the Options menu, select your processing options.
•
Modify the data files if necessary.
•
Next, select the Save As command and save the data under a new file name.
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3.1.5 Creating a New File
While working with PROSPER, new input or output data files can be created at any time. To
create a new file, from the File menu choose the New command. This command does not
actually create a new and separate file, but reinitialises the program input/output data.
3.1.6 Opening an Existing File
Existing data files can be opened quickly and easily at any time during the current working
session. To open a file, from the File menu choose the Open option. You can select one
of the following file types:
•
Input Data (. SIN)
•
Input and Analysis Data (. ANL)
•
Input, Analysis and Output Data (. OUT)
by using the “Files of Type” dropdown box.
The program displays a dialogue box in which the files matching your selection criteria are
listed in alphabetic order as in the following example:
Figure 3-1
File Dialog
The default data directory files are automatically displayed first. To open a file, point and
click the filename to recall and press ↵ or click on Open. The alternative method of
opening a file is to double-click on the file name. If the file you want is not listed, it is
possible that:
1) It is in a different sub directory
2) It is on a different drive
3) It is of a different file type.
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3.1.7 Saving a File
When files are opened in PROSPER, the program copies the selected file into the
computer's memory. Any changes to the file are made to the copy in memory. In the event
of a power failure or computer crash, these changes would be completely lost. To prevent
this, we recommend you save your data on a regular basis and especially before quitting
the program.
The Save command stores all the changes made in the active file. By default, the Save
command saves a file under its original name and to the drive and directory last selected.
You will be prompted to select one of the following file types:
Input Data (.SIN)
• Automatically saves the input file and corresponding .PVTP file.
Input and Analysis Data (.ANL)
• Automatically saves the analysis data and corresponding .SIN & .PVTP data
files.
Input, Analysis and Output Data (.OUT)
• Automatically saves the output results and corresponding .SIN, .PVTP & .ANL
files if a file of the same name exists in the selected directory, the file is
overwritten. If you do not want to overwrite an existing file, use the Save As
command.
3.1.8 Copying a File
The Save As command allows you to make more than one copy or version of an existing
file. With this command, you can save a file under the same name but to a different drive,
or under a different name on the same drive. Before saving a copy to another disk, we
recommend the file be first saved on your hard disk!
Selecting Save As prompts you to select one of the following file types:
•
Input Data (. SIN)
•
Input and Analysis Data (. ANL)
•
Input, Analysis and Output Data (. OUT)
The program displays a dialogue box listing all the current files that match your selection
criteria. Your default data directory is automatically displayed first. To copy a file, enter a
new name in the Filename field - up to eight characters are allowed. Select a different
directory or drive if desired, then press ↵ or click on OK.
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3.2 Preferences
The Preferences screen is used to customise the program to your particular requirements.
Click Preferences from the File menu to customise PROSPER. Click on the appropriate tab
at the top of the data entry section in order to change the option you require. The various
tabs are described below:
3.2.1 Screen
Figure 3-2
Preferences: Screen Tab
This tab is used to customise the appearance of the PROSPER front screen and all data
entry (dialog) screens.
Dialog Font
You can change the font type and size used to display all data entry screens. This may be
useful to make all dialogs smaller if you have a low-resolution screen or larger to improve
readability if you have a high-resolution screen. Use the Reset button to reset the dialog
screen font to its default value.
Status Screen
If you select Yes the screen status information will be continuously displayed and updated
as you use the program. If you select No the screen status information screen will not be
displayed (apart from whenever you open a new file).
Font Height
If the font height is modified then an attempt is made to scale the font so that all information
displayed in each panel on the status screen will be visible. This will vary depending on
the relative size of the program window to the total screen. If the font height is not modified
then some information may not be displayed as you vary the size of the program window.
Screen Font
Use this option to change the font type and size used to display information on the status
(front) screen of the program.
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Label Colour
Change the colour used to display labels on the status screen
Text Colour
Change the colour used to display text on the status screen
Background
Change the colour used for the background of the status screen
Box Colour
Change the colour used for the background of each panel on the status screen
Box Shadow
Change the colour used for the 3D shadow effect on the status screen panels
Box Highlight
Change the colour used for the 3D-highlight effect on the status screen panels
For all of the above “Colour” options the Choose button to the right will bring up a dialog
screen to select an appropriate colour.
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3.2.2 File
Figure 3-3
Preferences:
File Tab
Use this tab to customise various options relating to file management.
Default Data Directory
The directory where data files are normally stored.
Use the Browse buttons to browse for the appropriate directories.
Default Data Directory Choice
This option determines the directory that is used as the default in file dialog. The choices
are either to always use the default data directory (see above) or to use the directory of the
last file opened or saved.
Location of PROSPER.INI
The PROSPER.INI file is used to store all the customised information for your version of
PROSPER. The normal location is in the WINDOWS directory. If you have a network
installation of the program (or windows), then this option can to used to ensure that each
user of the program can maintain their own customised settings locally.
Location of ESP Databases
The ESP option in PROSPER is driven by a database of pumps, motors and cables. This
option allows you to specify the location of these databases.
Location of Hydraulic Pump Databases
The HSP option in PROSPER is driven by a database of pumps and turbines. This option
allows you to specify the location of these databases.
Location of Report Output Files
Use this option to specify the default location of output files from the reporting subsystem.
Location of User-Created Report Files
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Use this option to specify the default location of user-created report templates from the
reporting subsystem
Reload Last File On Start Up
Specify whether the last file that you were working with should be automatically reloaded
on program start up.
Number of File Names Saved
Specify the number of previously used files that are to be displayed on the file menu.
Confirm Calculations
Switch (on or off) the message that appears at the end of any calculation function.
3.2.3 Plot
Figure 3-4
Preferences
Plot Tab
Use this tab to set defaults for all aspects of the plot.
Always Use Plot Defaults
Each time a plot is done default values will be used rather than the last selected values for
each particular plot type
X Grid Blocks
Number of GAPs between grid lines on X-axis. (Range 1-20)
Y Grid Blocks
Number of GAPs between grid lines on Y-axis. (Range 1-20)
Plot Labels
Show or hide the plot labels.
Plot Scales
Show or hide the plot scales
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Plot Legend
Show or hide the plot legend. If the legend is hidden, the body of the plot will expand to fill
the whole window.
Scaling Method
Endpoint or rounded. Endpoint means the scales are taken from the exact extremities of
the data being plotted. Rounded means that ranges are chosen to surround the data but
with whole numbers ensured for the end points and the gridline intervals.
Grid Line Type
Select from dotted lines, dashed lines, solid lines or tick marks.
Mouse Readout
Switch the mouse cursor position readout no or off.
Date Stamp Title
Select to append the current data and time to the plot title or not
Line Thickness
To select the thickness of plotted lines
Vertical Font
Select the default font for all vertical text (Y-axis)
Horizontal Font
Select the default font for all horizontal text
Default Colours
Set the default colour scheme for the plot
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3.2.4 User Applications
Figure 3-5
Preferences
User Applications Tab
This tab allows you add up to four of your favourite or most-often used Windows
applications to the PROSPER menu. Although PROSPER has a very flexible reporting
system you may wish to use a spreadsheet (such as EXCEL), a word processor (such as
WORD) and a presentation package (such as Power Point) to build presentation quality
reports using PROSPER output in a slick and efficient manner.
Any output (plots and reports) produced by PROSPER is automatically copied to the
Clipboard. From there it can easily be pasted into one of the above-mentioned applications
using one simple keystroke. Using the power and flexibility of your chosen application,
high quality reports and presentations can be easily prepared.
All plots can be saved in Windows Metafile format. These can be easily read by a word
processing package or presentation graphics package and give the maximum flexibility for
user customisation.
All reports can be saved in TSV (Tab Separated Variable) format using the Export facility
that means they will automatically be tabulated when read into your favourite spreadsheet.
Enter a description and a command line for each application that you wish to add to the
PROSPER menu.
The description is the data that appears on the menu.
The command line is the full path name of the program you want to execute.
Use the Browse buttons to browse for the application you require. Use the Clear buttons
to initialise the appropriate application information.
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3.2.5 Limits
Figure 3-6
Preferences
Limits Tab
This tab allows you add up to specify Limiting Values for the following options.
Maximum AOF for OIL
Maximum AOF for GAS
Maximum AOF for RETROGRADE CONDENSATE
Minimum GLR Injected for GAP Performance Curves.
You can also control the display of large VLP values in SYSTEM calculations.
HSP calculation settings can be set in this screen as well.
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3.2.6 Units
Figure 3-7
Preferences
Units Tab
This tab allows you add up to specify the default Units Systems to use for new files.
If you set the option "Always Use Default Units" to "Yes". Then the units displayed for any
file read in will always be set to your default choice, regardless of the settings in the file.
3.3 Software Key Maintenance
Viewing the Software Key
The Software Key command activates the REMOTE software utility program that allows
you to read the software protection key. This facility lets you see what programs are
currently enabled, their expiry date, and user authorisation codes and key number. This
utility is also used to update the software key. Software keys must be updated when new
programs or modules are required or the key expiry date changed. Section 2.3 describes
how to use the REMOTE utility.
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3.4 User Correlations
PROSPER has been designed to accept outside calculation modules for fluid flow
correlations, Equation of State PVTP calculations, choke calculations (pressure loss
through restrictions) and inflow performance calculations. Users can obtain an authoring
kit from Petroleum Experts to enable the building of a compatible Dynamic Link Library for use in
PROSPER.
Before a DLL can be accessed, it must first be installed into PROSPER. This is done by
clicking File  User Correlations. Select either Flow Correlation, Equation of State Model,
Choke Correlation or Inflow Performance Model. PROSPER will display a list of the
currently installed DLLs of the selected type. To add a correlation, click Add and select the
appropriate file from the file dialogue. Click OK and it will be hooked into PROSPER.
MODEL
Flow Correlation
Equation of State PVTP
Model
Choke Correlation
Inflow Performance Model
EXTENSION
.COR
.EOS
.CHK
.RSM
Information about particular correlations can be obtained by clicking the Info button. A
screen similar to the following will be displayed.
Figure 3-8
Flow Correlation
Information
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3.5 Printing
3.5.1
Preparing to Print
Once you have selected a printer and selected the appropriate set-up options, printing
reports is simple. When you are ready to print, always verify your printer is plugged in, online and connected to your machine. The Printer Setup command of the File menu allows
you to select a printer and define its set-up options. The following option screen appears:
Figure 3-9
Printer Setup
3.5.2 Selecting a Printer
Select the correct printer from the list box provided. Only printers that have been installed
under Windows will be displayed. Next, select the port to which the printer is attached,
usually LPT1 for a local printer. Click on the Setup command button or press OK.
As all printers have varying printing capabilities, the dialogue box that appears will
correspond with the printer selected. Most printers allow you to select paper size and
source, page orientation and number of copies. The set-up screen example that follows is
for a HP 4000N printer.
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Figure 3-10
*Printer Setup Options
(Windows XP)
3.5.3 Printing Export Data
Prior to printing export data, it is always a good idea to save your data file(s). In the
unlikely event that a printer error or some other unforeseen problem occurs, this simple
procedure could prevent your work from being lost.
To print export data, select the Output menu and the Export option. Select the sections
you wish to report on the dialogue box. The program will lead you through a series of input
screens to set up the required report sections. From the main dialogue box, select a
destination for your data. Details of how to set up export data are given in Section 12.2.
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Figure 3-11
Output Results Reports
The appearance of printed reports is controlled by the export data set-up options that have
been set.
Click Setup to display the following screen:
Figure 3-12
Export Data Printer
Options
Select a suitable font and set the margins etc. that will be used for printed export data.
Only non-proportional fonts are allowed in reports to maintain vertical alignment of the
columns.
Â
PROSPER default font is recognised by most print set-ups. To avoid
potential printing problems, always set up the system to use a font that is
supported on your system prior to printing PROSPER export data for the
first time.
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Click OK to return to the output screen. Clicking Print initiates generation of the export
data and sends it to your selected destination.
Export data can be sent to your choice of:
•
Printer -
the primary printer as set up under Windows.
•
File -
Creates an ASCII data file and saves it. Clicking Print will display a
dialogue box that requests a file name and destination. Enter a suitable
file name (the program automatically appends a ".PRN" extension) and
click OK to save the file. The Fixed Format option saves a file in a printer
ready format that can be imported into a DOS based word processor or
text editor. Use the Tab Delimited format to save a file suitable for
importing directly into a spreadsheet such as EXCEL.
•
Clipboard - Clicking Print after selecting this option copies the data onto the Windows
clipboard. From the Clipboard, you can view, edit and paste the data
directly into another Windows application. E.g. a word processing
program. Tab delimited data can be pasted directly into spreadsheets.
•
Screen -
Clicking Print after selecting this option allows you to view the report on
the screen. Scroll through the data using the scrolling thumbs or arrows.
When finished viewing, click OK to return to the main menu.
3.5.4 Selecting a Exported Data to Print
You do not have to be in PROSPER to print a report. Providing you have previously
generated a report file (*.PRN), a report can easily be opened and imported into any word
or spreadsheet program. If the Tab Delimited option was selected, this will allow you to
easily create tables and/or format the data using your word processor.
3.5.5 Word Processing in PROSPER
The WordPad command on the File menu gives you direct access to the Windows word
processing package. This application can be used to make notes of your current analysis
for later inclusion in reports. If no alternative word processing package is available, you
can use WordPad to edit, format and print your reports.
3.5.6 Clipboard Command
The Clipboard command on the File menu gives you direct access to the Windows
clipboard viewer. This feature is useful for checking data input or intermediate results from
e.g. gas lift design calculations that are written to the clipboard by PROSPER.
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3.6 Command Buttons
The following command buttons are used in PROSPER.
All
This command button is used in the Equipment and Gas Lifted (safety
equipment) option screens. It will select all input parameters and data points
for automated editing.
Calculate
Performs the various calculations on the input parameters for the correlations
selected.
Cancel
Returns you to the previous screen. Any changes or modifications will be
ignored by the system.
Continue
Continues to the next input screen. Any changes to the fields will be saved
and retained in memory for later calculations. A warning message will be
displayed when fields requiring input data are left blank.
Copy
To copy existing data points, select the line entries to duplicate and click on
Copy.
Next, select the destination line(s) and click on Copy again.
Subsequent line entries will be not be overwritten by this operation.
Correlations Displays the results of any matching performed under the VLP/IPR Match
option.
Delete
This command button is used in the Equipment and Gas Lifted (safety
equipment) option screens. It allows you to delete individual or several data
points.
To delete, select the line entries to erase and click on Delete. If you wish to
delete all existing line entries, click All and then Delete. The program will
clear the input screen.
Done
Returns you to the previous menu.
retained in memory by the program.
Edit
This command button is used in the main Equipment screen. One or more
items can be modified at a time. When used with 'All', all items will be
selected for editing.
Export
Brings up the Data Export interface. This will be specific to the data on the
active window.
Help
Provides on screen help for PROSPER. For general information, press the
'ALT' and 'H' keys together in the Main menu, or the Index button under any
help screen. Specific help screens are also available for each window.
Import
Calls up the general import interface that allows you to grab data from any text
file. This button will usually be found where tabular data is to be input.
Insert
This allows you to add one or several data points providing there are sufficient
entry fields. Select the line number where you wish to add a new entry and
click on Insert. The program will move existing line entries down to
accommodate the inserted line(s).
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Any changes or modifications will be
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Main
Returns you to the Main Application Menu. Any changes or modifications will
be saved and retained in memory by the program.
Match
Displays a variable screen where you may enter data in order to adjust
existing correlations to fit real data.
Move
Move allows you to re-arrange data points. Select the line(s) to transfer and
click on Move. Next, select the destination line(s) and click on Move again.
Subsequent line entries will be moved down to accommodate the transferred
line(s).
Plot
Plots any calculated results and displays them on screen. Hard copies of the
screen display can be printed by selecting the Hardcopy command button on
the Plot screen.
Recall
Allows you to recall and existing PVTP file. You will be prompted for the
directory and name of the file.
Report
Calls up the reporting interface with a report that is specific to the active
window. This is generally found on windows that display the results of
calculations. You can then choose to print this report. The report is generated
from a system report template.
Reset
Resets the Match parameters in order to reinstate the original textbook
correlations.
Save
Saves a current PVTP file. If this is a new data file, you will be prompted for a
file name.
Summary
Displays a summary screen of the input equipment parameters or system
units.
The following command buttons are used in the Plot Menu and Plot screens.
Clipboard
Sends black and white or colour copies of the screen plot to the Windows
Clipboard where it may be retrieved by a word processing program for
inclusion in reports.
Colours
Allows you define the screen display colours of your plot labels, scales, grids,
etc.
Finish
Returns you to the previous menu or screen.
Hardcopy
Generates black and white or colour print copies of the screen plot. It is
automatically sent to the device selected in \.
Labels
Allows you to label your plot. All plot labels are stored in memory and saved
when Output files are generated.
Replot
Re-displays the original screen.
Scales
Allows you to re-define the minimum and maximum values for the X and Y
plot axes.
SEPTEMBER 2003
PROSPER MANUAL
4 Data Input - General
This section describes the PROSPER main menu and the input data required before an
analysis can be performed. Data should be entered by working through the PROSPER
menus from left to right and top to bottom. The following menus are described in this
section:
•
Main menu
•
Options menu
4.1 PROSPER Main Menu
All PROSPER functions are listed as menu options. Simply select the required menu and
choose an item from the list displayed. This will activate an option or display the relevant
screen.
Problem solving with PROSPER is approached systematically by working from left to right
through the main menu. Calculation menus are activated only when the necessary input
data has been entered.
To start PROSPER, select the appropriate icon and press ↵ or double-click the program
icon. A screen similar to the following will appear:
Figure 4-1
Main Menu
The menu options across the top of the screen are the PROSPER main menu options.
Each is described below.
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CHAPTER 4 – GENERAL DATA INPUT
4.1.1 File
The File menu is a management menu with commands that enable you to open, save or
create new data files. You can use this menu to define your default data directory, printer
set-ups options and hook in external DLLs. A facility for accessing other Windows
programs via PROSPER is also provided.
4.1.2 Options
The Options menu is the starting point of PROSPER and the key to the program. Use this
menu to define your application and principal well features such as - prediction method,
artificial lift type and fluid type. The options you select are unique to the current file and
apply until changed by the user, or another file is recalled. These options also determine
the subsequent screens, menus and commands that are displayed.
4.1.3 PVT
Use the PVT menu to define well fluid properties and select fluid property correlations. PVT
correlations can be modified to match laboratory-measured data using a non-linear
regression technique. Alternatively, detailed PVT data may be entered in tables.
4.1.4 System
The System menu is used to define the well's downhole and surface equipment as well as
the reservoir inflow performance. When applicable, gas lift and ESP or HSP equipment
data for artificially lifted wells are entered from this menu.
4.1.5 Matching
The Matching menu allows comparison of field data with calculated pressure drops in well
tubing and surface piping. All available correlations can be compared to allow selection of
the model that best suits your field conditions.
4.1.6 Calculation
The Calculation menu provides you with the relevant calculation options. Calculations to
determine pressure and temperature profiles, perform sensitivity analyses, make gradient
comparisons and generate lift curve tables are available in this menu.
4.1.7 Design
ESP, HSP and PCP sizing as well as gas lift mandrel placement and valve setting pressure
calculations are available from the Design menu. Access to the databases that hold gas lift
valve, ESP, HSP and PCP equipment characteristics is via the Design menu also.
4.1.8 Output
The Output menu is used to generate reports, to export data and to plot data. Report
templates are provided and user templates can also be defined. The data used can be
input data, analysis data, results or plots. Reports can be saved in various file formats
(RTF, TXT and native) and can be displayed or sent to a printer. Export data can be
viewed on screen, sent to the Windows clipboard, sent to a printer or saved in a file. Plots
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can be printed directly, saved to a report file or a Windows metafile. Selected plots can
also be sent to the clipboard where they can be retrieved by other Windows-based
programs.
4.1.9 Units
This menu is used to define the input and output units of measurement. A flexible system
of units is provided allowing you to customise the internal units system.
4.1.10 Help
Provides on-line help for PROSPER. You can get help on specific tasks, fields or
commands. Help is also given on the keyboard and miscellaneous Windows commands.
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CHAPTER 4 – GENERAL DATA INPUT
4.2 Options Selection
The Options menu is used to define the characteristics of the well. The options selected
establish the input data required and the calculation options available. The selections
made apply to the current session. The data entry screens, input fields and variables are
limited to those relevant to your particular application. Input options may be changed at
any stage of the processing. New choices may require other information to be supplied.
Therefore the user is advised to ensure that all relevant input is still valid for the new option
selection. The System | Equipment | Summary is a convenient way to check that the
equipment description is correct for new Options.
To access the Options menu, point to the menu name and click the mouse or press ALT O.
The following data entry screen will appear:
Figure 4-2
System
Options
Summary
The entry screen is divided in two sections - System options and User information.
Under the System options section, define your well characteristics such as fluid type, well
completion, lift method, etc. These selections determine information you will be required to
enter later. The lower section of the screen comprises the header information and
comments that identify your well and will appear on the report and screen plot titles.
Option Selection
To select an option, click on the arrow to the right of the required field. The list of available
choices will be displayed.
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4.2.1 Fluid Description
4.2.1.1 Fluid
•
•
•
Water and Oil (Producers and Injectors)
Dry and Wet Gas (Producers and Injectors)
Wet gas is handled under the assumption that condensation occurs at the
separator. The liquid is put back into the gas as an equivalent gas quantity.
The pressure drop is therefore calculated on the basis of a single-phase gas,
unless water is present.
Retrograde Condensate (Black Oil Model or Compositional)
Black Oil or Compositional models can be used. These models take into
account liquid drop out in the tubing.
4.2.1.2 Method
•
•
Black Oil
This option uses industry standard Black Oil models. Five correlations are
available for oil producers. For gas condensate systems an internally developed
model is used. These correlations can be adjusted to match measured data
using non-linear regression.
Equation of State
Reservoir fluid is modelled by pseudo components having user-specified
properties. The original Peng-Robinson equation of state is used by PROSPER
to predict PVT properties.
4.2.1.3 Equation of State
This sub-menu is available in case Equation of State is selected under “Method”
•
Peng-Robinson (Equation of State PVT Only)
User EOS DLLs can also be linked into PROSPER.
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CHAPTER 4 – GENERAL DATA INPUT
4.2.1.4 Separator
•
•
Single Stage
This available for black oil option for following fluids:
• Oil and water
• Dry and Wet Gas
• Retrograde Condensate
Two Stage
This option is available for Black oil model in case of Oil and Water fluid type
only.
Separator and tank properties are entered and recombined by PROSPER.
•
Multi Stage (Compositional)
This option is available for Equation of State option only.
Up to 5 stages of separation can be modelled for compositional applications.
4.2.1.5 Emulsions
•
No or Emulsion + Pump viscosity correction
Select Emulsion + Pump viscosity correction to allow input of Emulsion viscosity
in the PVT section. This option must be selected to turn on ESP or HSP
viscosity corrections.
4.2.1.6 Hydrates
•
Disable Warning or Enable Warning
Select Enable Warning to allow flagging of hydrates formation in calculation
screens. You will need to go to the PVT section and enter or import the
hydrates formation table.
4.2.1.7 Water Viscosity
•
Use Default Correlation or Use Pressure Corrected Correlation
When the default correlation is used, the water viscosity will be sensitive to the
water salinity and temperature. When the pressure corrected correlation is
used, the water viscosity will be sensitive to the water salinity, temperature and
pressure.
4.2.1.8 Water Vapour
•
No Calculation or Calculate Condensed Water Vapour
This option is only available for ‘Dry and Wet Gas’ mode. If ‘Calculate
Condensed Water Vapour’ is selected, the condensation of water vapour will be
taken into account when performing pressure drop calculation.
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4.2.2 Well
4.2.2.1 Flow Type
•
Tubing Flow
•
Annulus Flow
This option models production up the casing / tubing annulus.
Tubing + Annulus Flow
This option models production up the tubing and annulus space simultaneously
•
4.2.2.2 Well Type
•
•
Producer
Injector
Injection of single-phase water or gas is supported.
4.2.3 Artificial Lift
4.2.3.1 Method
The following 4 lift method options are available when Oil is selected as a fluid type.
• Naturally Flowing
No artificial lift.
• Gas Lifted
Three different approaches are provided. Annular gas lift is handled by
PROSPER. If the Flow Type is Annular Flow and a Gas Lift method is selected,
then PROSPER automatically switches to model gas injection down the tubing,
and production up the annulus.
• Electric Submersible Pump
An ESP installation can be analysed or designed using this option.
The user has choice to select standard pump or Subsea Pump (framo)
• Hydraulic Drive Downhole Pump
An HSP installation can be analysed or designed using this option.
•
Progressive Cavity Pumps
A PCP installation can be analysed or designed using this option.
•
Coil Tubing Gas Lift
Coil Tubing with gas lift can be analysed or designed using this option.
4.2.3.2 Type
If Gas Lift is the chosen method, then the following types are available.
• No Friction Loss In Annulus
It is the classic approach for the annulus gas gradient. The pressure drop due
to friction in the annulus is ignored and the gas gradient is determined by the top
casing pressure and the temperature profile.
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CHAPTER 4 – GENERAL DATA INPUT
•
•
Friction Loss In Annulus
The pressure drop due to friction in the annulus is taken into account, but the
top casing pressure is assumed constant. If this option is selected the tubing
equipment screens will automatically change and require tubing OD and casing
ID data to be entered.
Safety Equipment
Surface delivery lines, chokes, the gas lift injection string and safety valves in
the annulus are taken into account. Top casing pressures will change with
injection rate.
If Hydraulic Drive Downhole Pump is the chosen method, then the following types are
available.
•
•
•
Commingled Annular Supply
The power fluid for the turbine is supplied via the annulus and returns to
surface, commingled with the produced fluid via the tubing.
Commingled Tubing Supply
The power fluid for the turbine is supplied via the tubing and returns to surface,
commingled with the produced fluid via the annulus.
Closed Loop Supply
The power fluid for the turbine is supplied via the outer annulus and returns to
surface via the inner annulus. The reservoir fluid is produced through the
tubing. There is no commingling of produced and power fluids.
If Progressive Cavity Pump is the chosen method, then the following types are available.
•
•
Sucker Rod Drive
The program will assume that you have a surface drive head from which you
require rods in order to move the rotor across the pump.
Downhole motor drive
The program assumes that you have a downhole motor instead of surface drive
motor.
4.2.4 Calculation Type
4.2.4.1 Predict
The program is capable of predicting either pressure only or pressure and temperature
changes simultaneously.
• Pressure Only
If this option is taken, the flowing temperature profile must be entered. This
calculation option is fast and provides accurate pressure profiles.
• Pressure and Temperature (Land and Off shore)
This option will calculate both pressure and temperature profiles using the
method specified in Temperature Model.
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4.2.4.2 Model
Enthalpy Balance
This rigorous thermodynamic model considers heat transfer by conduction, radiation, and
forced and free convection. Heat transfer coefficients are calculated using values held in a
user-definable database. The temperature prediction calculations are transient, allowing
sensitivities against flowing time to be run. This temperature model requires considerably
more input data and computation time for either Predicting Pressure Only or the Rough
Approximation temperature model.
The production riser is properly taken into account. Therefore the heat loss prediction
between the seabed and wellhead will be accurate. Due to increased computation times,
we recommend that this option be used only when temperature prediction rather than
pressure loss is the required result (for e.g. process calculations and material selection).
The Enthalpy Balance temperature model is capable of accurate flowing temperature
prediction for a wide range of conditions.
The temperature prediction is useful for generating temperature profiles in:
• long pipelines
• subsea wells
• high pressure/temperature exploration wells
• predicting temperature/pressure profiles to help predict wax/hydrate
deposits.
• These models also account for Joule-Thompson Effects.
The temperature calculation must commence from a known condition. This is usually the
reservoir pressure and temperature. As a consequence, calculating from a downstream
node (unknown temperature) to an upstream node (known temperature) is not meaningful
Rough Approximation
Calculates the heat loss from the well to the surroundings using an overall heat transfer
coefficient, the temperature difference between the fluids and the surrounding formation
and the average heat capacity of the well fluids. The geothermal gradient entry screen is
used to input formation temperatures (e.g. from logging runs) at measured depth points. A
minimum of the surface and first node temperatures are required. Temperatures entered
should be the extrapolated static temperatures, and should not be confused with the entry
of measured flowing temperatures required for the Predicting pressure only case.
The Rough Approximation temperature model requires calibration using measured
temperature data. It is not accurate in a predictive mode.
Improved Approximation
Calculates the heat loss from the well to the surroundings using an overall heat transfer
coefficient (which can be varied along the well bore and pipeline), the temperature
difference between the fluids and the surrounding formation and the average heat capacity
of the well fluids. The geothermal gradient entry screen is used to input formation
temperatures (e.g. from logging runs) at measured depth points. A temperature gradient in
the sea can be entered for offshore applications. A minimum of the surface and first node
temperatures are required. Temperatures entered should be the extrapolated static
temperatures, and should not be confused with the entry of measured flowing temperatures
required for the Predicting pressure only case.
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The Improved Approximation temperature model requires calibration using measured
temperature data. It is not accurate in a predictive mode.
4.2.4.3 Calculation
•
Full System
Calculations for pipelines, tubing and reservoir
•
Pipeline Only
Calculations for pipelines only
4.2.4.4 Output
•
•
Show calculating Data
Hide calculating Data
Select Hide to speed up calculations by not updating calculation screen
displays. This will automatically be set to Hide when run from GAP
4.2.5 Well Completion
4.2.5.1 Type
•
Cased Hole or Open Hole
This selection determines the appropriate IPR Completion models to use.
4.2.5.2 Gravel Pack
•
Yes or No
Gravel pack pressure drops will be calculated when Yes is selected.
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4.2.6 Reservoir
4.2.6.1 Type
•
Single Branch or Multilateral Well
In the single branch option the IPR screen comes with various standard inflow
models from which the user selects one.
For the multi-lateral selection, the IPR screen requires detailed drawing of the
downhole completion.
4.2.6.2 Gas Coning
• Yes or No
Rate dependant GOR will be modelled and calculated when Yes is selected.
This option is only available for Single Branch type wells.
4.2.7
Header Information
These fields are optional. The details entered here provide the header information that
identifies your well in the screen plots and printed reports. The Comments area is used to
enter free format text describing the details of the analysis. A Date stamp feature is
provided to mark either the comment text or the header data for future reference.
We recommend that comments be used to summarise any assumptions made in your
analysis. Whenever an existing model is modified, appending a summary of changes and
a date stamp will greatly assist current and future users working with the file.
SEPTEMBER 2003
PROSPER MANUAL
5 PVT Data Input
5.1
Introduction
To predict pressure and temperature changes from the reservoir, along the well bore and
flow line tubular, it is necessary to accurately predict fluid properties as a function of
pressure and temperature. The user must enter data that fully describes the fluid
properties or enables the program to calculate them. There are three possible approaches:
1. If only limited data is available (a minimum of solution GOR, oil gravity, gas gravity and
formation water salinity for oils) the program will use one of several correlations to
calculate the fluid properties. The user decides, the correlation to be selected.
2. If both limited fluid property data and PVT laboratory measured data is available, the
program can be used to tune the standard correlations to best fit the measured data
using a non-linear regression technique. The matched correlations can then be used to
calculate all the fluid properties required in the multiphase flow calculations.
3. The PVT data may be also entered in tabular format. The program can be instructed to
use the tabular data where available. Data should be available to cover a range of
temperatures. Normally this is not recommended.
The program also allows fluid properties to be calculated and plotted for specified pressure
and temperature ranges. The PVT menu has three options - Report, Input and Export.
Select Report to inspect previously entered data, Export to save data to a text file, or Input
to set up a new problem or edit an existing one.
Recommended Steps
Only Limited PVT Data Available ( Minimum required for correlations)
•
Enter data as requested on PVT input data screen and select correlations that
are known to best fit the region or oil type.
Limited PVT Data and Laboratory Measured Data Available
•
Enter the data requested in the PVT input data screen.
•
Enter PVT laboratory data in the PVT  Match data menu. The laboratory PVT
data and the fluid properties entered on the data input screen must be
consistent.
Flash Data must be used. Up to 5 tables of laboratory
measurements made at different temperatures may be entered. Use the Tables
buttons to switch between tables. Click OK to return to the PVT input screen.
•
At this point, you can optionally Calculate PVT using a correlation and Plot the
calculated and match data to see how closely the non-optimised correlation fits.
•
Select Regression, then Match All. A non-linear regression will be performed to
best fit each correlation to the measured lab data. Once the calculation is
finished, select Parameters and identify the correlation that best fits the
measured data. This correlation should then be selected and this modified
correlation will be used in all further calculations of fluid property data. The fit
parameters are the multiplier and shift applied to the correlation in order to fit the
lab data. If the correlation were a perfect fit to the match data, Parameter 1
would be set to 1.0 and Parameter 2 would be zero.
•
In order to see how well the tuned correlations fit the data, on the regression
screen there is plot utility, which will plot the variable values from the matched
correlations, and the data entered simultaneously, to allow the user to see how
good the fit is. Select Plot to display both the calculated and measured PVT
2 - 28
CHAPTER 5 - PVT DATA INPUT
data. Select the Variables option on the plot menu bar to choose the fluid
property data to display.
PVT Data supplied as Tables.
•
Select Tables and enter data in the tables.
Because it interpolates the tables, PROSPER cannot account for
temperature changes when PVT data is available for only one temperature.
In such cases, the Limited PVT recommendations should be followed. If no
data for a particular variable is available, the program will calculate the
necessary values using the selected correlation. For the correlations to take
over, there must be no table entries for a particular variable at any temperature.
Â
Whether PVT tables have been input or not, PROSPER will use correlations
unless the Use Tables box on the PVT Input screen has been selected. Do not
select Use Tables unless complete PVT tables have been entered. Data at only
one temperature (e.g. reservoir temperature) is not adequate.
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5.2
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Black Oil - Oil and Water
5.2.1
Input Data
Select the PVT Input option from the main menu to display the following PVT Input data
screen:
Figure 5-1
PVT Input Screen
Enter the required data in the fields provided. You can move from one box to another by
pressing the TAB key. Next, select a Pb, Rs and Bo correlation and a viscosity correlation
to use then click OK.
Â
Enter the oil solution GOR. This should not include free gas production. For gas
production in wells producing injection or gas cap gas the solution GOR should
still be entered. The balance of “free” gas production is accounted for elsewhere.
Mole Percent CO2, N2 and H2S refers to the separator gas stream composition.
5.2.1.1 Emulsions
If you have allowed emulsions on the options screen you will have the option to select
where the emulsion viscosity corrections will take place. The Flowline Emulsion Data
button will take you to the Emulsion Data entry screen.
You can also enter the water cut at this point that will then be used to calculate the
emulsion viscosity in the PVT calculation section. Refer to section 5.2.10 for more
information.
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PROSPER MANUAL
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CHAPTER 5 - PVT DATA INPUT
5.2.2
Tables
In PROSPER the PVT data can also be entered as tables. This is done by clicking Tables.
Up to ten separate tables may be entered, each at a different temperature. If the program
requires data for which there are no entries at all, it will calculate values using the selected
black oil correlation. The program will use the data from the tables in all further
calculations provided the Use Tables option has been selected on the input data screen.
This option should be used only when extensive table data is available for a range of
temperatures.
Figure 5-2
PVT Tables
Rather than entering the values by hand, PROSPER can read in tables of Black Oil PVT
properties. To do this, click the Import button from the Tables screen, and you will be
prompted to enter the name of an ASCII file containing the PVT data. Petroleum Experts’ PVT
Package can be used to calculate and export Black Oil PVT tables. An example of the
PVT Table import file format is given in Appendix E.
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CHAPTER 5 – PVT DATA INPUT
5.2.3
5 - 28
Match Data
Click the Match Data button and enter PVT laboratory measured data to match to as
shown on the example screen below:
Figure 5-3
PVT Match Data Screen
Since gas evolution in the tubing is a constant composition process, Flash data, not
differential liberation data should be used for matching. For each match data table, enter
the temperature and bubble point, then enter pressure versus gas oil ratio, oil FVF and oil
viscosity. Where data is incomplete or not available, leave the field blank. Use the GOR
and FVF at bubble point plus the viscosity if available. Enter only the minimum number of
points to ensure a good match.
Â
Where only differential liberation PVT data is available, a PVT simulation
program can be used to calculate the flash properties using a model that has
been matched to the lab data.
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CHAPTER 5 - PVT DATA INPUT
5.2.4
Regression
This option is used to perform the non-linear regression, which adjusts the correlations to
best fit laboratory measured PVT data. The non-linear regression matching technique can
be used on up to five PVT match tables, each with a different temperature. The following
PVT properties can be used as match variables:
Pb
GOR
FVF
Oil viscosity
Bubble point pressure.
Gas oil ratio versus pressure.
Oil formation volume factor versus pressure.
Oil viscosity versus pressure.
It is not necessary to match on all properties for all applications. In cases where the PVT
data is incomplete or of poor quality, better results can often be obtained by matching on
the best characterised parameters only. However, because bubble point can be difficult to
accurately predict from correlations, it is recommended that, where possible, it is used as a
match parameter. The minimum data required to perform a regression match is the bubble
point and GOR.
Â
The form of the correlations for FVF is different above and below the bubble point. If
the FVF at bubble point is not available, the regression may not achieve good results.
When matching the oil FVF, always enter data at the bubble point. Do not enter many
match points, use the minimum number to define the shape of the correlation curves.
In most cases, only data at the bubble point is required.
Figure 5-4
PVT Regression Screen
5.2.4.1 Match
From the Regression screen, individual correlations can be matched to selected measured
PVT data by:
•
•
•
Selecting the correlations
Selecting the fluid properties to match to
Clicking Match
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5.2.4.2 Match All
All correlations can be matched to all the fluid property data in one keystroke by selecting
the Match All command button.
5.2.4.3 Parameters
Having performed the matching process, the match parameters are displayed by clicking
the Parameters button. The non-linear regression technique applies a multiplier Parameter 1, and a shift - Parameter 2 to the correlations. The standard deviation is also
displayed, which represents the overall closeness of fit. The lower the standard deviation,
the better the fit. The best overall model is the one that has Parameter 1 closest to unity.
5.2.4.4 Viewing the Match Parameters
The Parameters button displays the PVT correlations parameters screen. This shows the
match parameters and the standard deviation for each matched correlation. Use these
statistics to select the best correlation for your application. A plot should be made (refer
calculation and plot sections) and a visual check of the fit quality performed before making
your final selection. The match parameters can all be reset (i.e. returned to the unmatched state) by selecting the reset option. The following is an example of a correlation
parameters screen:
Figure 5-5
PVT Match
Parameters
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CHAPTER 5 - PVT DATA INPUT
5.2.4.5 Matching FVF above Bubble Point
The standard correlations do not always accurately model the FVF above bubble point
(especially for heavy or waxy oils). Additional match parameters (Parameter 3 and 4) have
been introduced to allow the FVF to be independently tuned below (P1 and P2) and above
(P3 and P4) the bubble point.
In all circumstances, always enter match data at the bubble point to ensure that no
discontinuities occur.
5.2.5
Calculations
In order to make a plot or listing of fluid property data, PROSPER must first calculate the
values over a specified range of temperatures and pressures. Using the calculated data
points, plots of fluid properties versus temperature or pressure can be generated. The
following is an example of the PVT  Calculations screen. If the correlations have been
matched, then the fluid properties will be calculated using the modified correlations.
Â
The calculation procedure is optional and used only to generate fluid property data
for display and quality control purposes. During the computation of a pressure
traverse, PROSPER calculates fluid properties at each pressure and temperature
step or node as required by the application.
5.2.5.1 Calculating PVT Data
Figure 5-6
PVT Calculation
Setup
To generate tables and plots of PVT data:
• Select Correlations (use the best matched one)
• Select Automatic generation of Data Points
• Enter the temperature range and number of steps
• Enter the pressure range and number of steps
• Click OK
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CHAPTER 5 – PVT DATA INPUT
•
9 - 28
Click Calculate to compute PVT data for the entire range of pressures and
temperatures required by your application. The following calculation screen will
be displayed:
Figure 5-7
PVT calculation
Results
The PVT section can be used as a convenient calculator by entering user selected data
points, then entering specific temperatures and pressures to calculate fluid properties.
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5.2.5.2 Displaying the Calculated Data on the screen
The calculated data is displayed on the screen as default. However, you have the option of
choosing the calculated variables to be displayed by using Layout button on the screen
above. Pressing this displays the list of all calculated variables, out of which the selection
can be made.
Figure 5-8
PVT calculation Layout
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5.2.5.3 Plotting the Calculated Data
The calculated data can be displayed on a plot. The variables, which are plotted, are
defined under the Variables option on the plot. After performing a PVT calculation click
Plot from the PVT calculation screen. Display the selected results by following this
procedure:
•
Click Variables.
•
Select Pressure for the X-axis.
•
Select GOR for the Y-axis.
•
Click OK to display a plot showing both the calculated values and the measured
values similar to the following:
Figure 5-9
PVT Results Plot
Carefully examine the PVT plots for consistency with your match data. If necessary, select
a different correlation and repeat the PVT calculations until you are satisfied with the
results.
5.2.5.4 Saving PVT tables from Calculated Data
The calculated data can be saved in the form of .ptb files by the button provided at top of
the calculation output screen in Figure 5-7.
There is also the possibility of transferring the displayed calculation to the Tables by
pressing on the Tables button.
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5.2.6
Saving the PVT Data
This option allows a PVT data set to be saved under a separate name. A dialogue box will
appear prompting you to name the PVT file. The PVT extension is automatically provided
by the program. If you omit this step, the program will automatically save the (matched)
PVT data in a .PVT file with the same name as the input (.SIN) file.
5.2.7
Recalling a PVT File
This option allows a previously saved PVT data set to be recalled into the open file. A
dialogue box will appear prompting you to select a PVT file. If this step is carried out after
recalling a .SIN file, this will overwrite the PVT data from the original file.
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5.2.8
For multi-well projects, set up matched PVT models for each producing area first.
This will save time and reduce the potential for error by recalling the relevant PVT
data into each well file.
Correlations
This options displays the match parameters and standard deviations for each matched
correlation. See section 5.1.4.4 for a more detailed explanation of this
5.2.9
Composition
In the PVT Input Data screen, click the Composition button, and PROSPER will use the PVT
properties (Oil Gravity, GOR) to estimate the composition of the reservoir fluid. The
estimated composition is used internally by PROSPER to calculate thermodynamic
properties needed in the choke and enthalpy balance temperature models. The following
is an example of an estimated Black Oil composition:
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CHAPTER 5 – PVT DATA INPUT
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Figure 5-10
Estimated Composition
Click BI Coefficients and PROSPER will display the Binary Interaction coefficients to be
used in an EOS description of the fluid. An example BI Coefficients display is shown
below:
Figure 5-11
BI Coefficients for
Estimated
Composition
Estimation of reservoir fluid composition is available for Oil and Retrograde Condensate
fluids.
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5.2.10 Non-Newtonian Fluid
PROSPER can model the effect of non-Newtonian fluids. The implementation of the model
is based on drilling fluid models developed by TotalFinaElf. This will enable foams in heavy
oils to be modelled more accurately.
Figure 5-12
PVT input data
To enter the required non-Newtonian fluid viscosity data, select Rheological Parameters
from the PVT Input Data screen:
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CHAPTER 5 – PVT DATA INPUT
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Figure 5-12
Viscosity Modelling
(Information
Required)
5.2.11 Emulsions
PROSPER can model the effect of Oil/Water emulsions on mixture viscosity for Black Oil
PVT systems. The behaviour of emulsions in producing well equipment is not well
understood. Emulsion PVT in PROSPER provides a means to assess possible effects of
increased emulsion viscosity by curve fitting experimentally determined data. It must be
emphasised that the method is empirical and does not represent any rigorous model of
emulsion behaviour.
In the laboratory, stable emulsions can be prepared from many crude oil / water systems.
Emulsion samples in surface separation equipment does not necessarily imply that
emulsions are present in the well. Field experience shows that the effect of emulsions is
usually less than predicted by laboratory tests. Emulsion PVT should be used with caution
and only when it is certain that emulsions are present and it is necessary to evaluate their
effect on calculated pressures.
To enable emulsion PVT in PROSPER, the Emulsion option must first be selected on the
Options screen. Emulsion viscosity will replace the mixture viscosity for selected elements
of the production system. Experimental or empirical emulsion viscosity data can be
entered and curve-fitted using non-linear regression. The fitted curve is used to optionally
replace the oil/water mixture viscosity in IPR, VLP and pump calculations. When selected,
emulsion viscosity for the user-entered value of water cut will be substituted for the fluid
mixture viscosity.
Drop down the Emulsion box and select from the following:
•
No viscosity corrections
Turns off emulsion viscosity corrections
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•
Everywhere
Emulsion viscosity for IPR, VLP and pump if present
•
Tubing and Pipe
Emulsion viscosity for casing, tubing and pump if present
•
Pump only
Emulsion viscosity for pump only
•
Pump and Above
Emulsion viscosity in pump and tubing above pump
•
Tubing + Pipe (not pump)
Emulsion viscosity in tubing and pipe only
The selection of system elements affected by emulsion can be changed at a later time
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Even if No Emulsion Corrections has been selected on the PVT screen, pump
viscosity corrections will be applied whenever Options  Emulsions is selected.
Produced fluid viscosity, not emulsion viscosity, will then be used for corrections.
To set up the emulsion model, select Emulsion Everywhere, (otherwise emulsion viscosity
will not be active for the PVT calculations) then click the Emulsion Data button and the
following screen will be displayed.
Figure 5-13
Emulsion Match Data
Entry
The screen is divided into 3 sections:
•
Emulsion Data
•
Experimental Parameters
•
Match Parameters
PETROLEUM EXPERTS LTD
Experimental data for matching
Experimental base conditions
Results of regression
CHAPTER 5 – PVT DATA INPUT
17 - 28
The pressure and temperature that correspond to the experimental conditions are entered
in Experimental Parameters. This enables PROSPER to correct the emulsion viscosity for
temperature and pressure.
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Emulsions Everywhere must be selected before plotting the emulsion viscosity
curve. The emulsion viscosity entered for zero water cut should be compatible
with the 100% oil viscosity at the experimental temperature and pressure.
Emulsion viscosity is modelled as a function of water cut in 3 stages:
• Sharp increase at low water cut
• Plateau with a constant maximum viscosity for intermediate water cuts
• ‘Tail’ that declines to the viscosity of water after the plateau
The parameters Left and Right Water Cut for Maximum Viscosity define the maximum
plateau region. To calculate emulsion viscosity:
• Enter pairs of water cut and emulsion viscosity data points in the Emulsion Data
table.
• Enter the Experimental Parameters
• Click the Match button.
When the regression has stopped, click Plot to display the matched mixture viscosity:
Figure 5-14
Emulsion Viscosity Plot
Match data is plotted as crosses, whereas the calculated viscosity is shown as a solid line.
When Emulsions Everywhere have been selected, the calculated Oil Viscosity in the PVT
section will be replaced by the emulsion viscosity for the value of Water Cut entered.
5.2.12 Hydraulic Pump Power Fluid Data
If you have selected HSP (Hydraulic Pump) as the Artificial Lift method, then you must
supply some details of the power fluid in order that its fluid properties can be estimated.
There are two choices for power fluid type:
• Water
• Other Fluid
If you select Water, then the only other data required is the salinity of the power fluid. The
program will then estimate fluid properties using the normal water PVT model.
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If you select “Other Fluid”, then you have to enter tables of fluid properties that the program
will interpolate from. The program will never extrapolate so please ensure that your tables
cover the expected ranges of pressures and temperatures. Click the Properties button and
the following screen will be displayed.
Figure 5-15
Power Fluid Properties
Data Entry
Up to ten tables of data may be entered. Please ensure that the tables span the expected
range of conditions that will be encountered.
5.2.13 Hydrates Formation table
If you have selected Enable Warning as well as the Hydrates option, then you must supply
the pressure – temperature lookup table for hydrates formation
Click the | Hydrates button and the following screen will be displayed.
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Figure 5-16
Hydrates Formation
Table Data Entry
Up to one hundred data points may be entered. Please ensure that the table spans within
the expected range of conditions that will be encountered.
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5.3
Black Oil - Dry And Wet Gas
All the condensate drop out is assumed to occur at the separator. Free water production in
the tubing is considered. For pressure drop calculations, an equivalent gas rate is used
which allows for the condensate and water production by ensuring that a mass balance is
observed.
5.3.1
Input Data
When Dry and Wet Gas is selected as the PVT option, the following Input data screen is
displayed:
Figure 5-17
Dry and Wet Gas PVT
The bottom part of the screen will only appear when the option ‘Calculate Condensate
Water Vapour’ is selected in the Option section. If this option is selected, the effects of
condensation of water vapour on the pressure drop calculation in the tubing / pipeline will
be taken into account.
This model applies to most gas wells. The condensate production is included in the gas
stream as an increase in density - the flow remains single-phase gas plus free water if
present. The separator temperature is assumed to be the same as the top node
temperature. If there is significant hydrocarbon liquid drop out in the tubing, a retrograde
condensate model should be used.
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The Gray VLP correlation has an internal PVT routine that models the effect of
liquid dropout in the tubing. This overrides the Dry and Wet gas PVT.
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CHAPTER 5 – PVT DATA INPUT
5.3.2
21 - 28
Match Data
Please refer to Match data in Section 5.2.3.
matched:
• Z factor (gas compressibility factor)
• Gas Viscosity
• Gas FVF
The following fluid properties can be
Matching operations are carried out as for Oil PVT. Refer to Section 5.2.4
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Produced gas is generally saturated with water at reservoir pressure and
temperature. Some water of condensation always drops out at the separator.
This water has a minimal effect on calculated bottom hole pressures. The WGR
considers free water production at the sandface.
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5.4
Black Oil - Retrograde Condensate
The PROSPER Retrograde condensate (Black Oil) model has been developed in house by
Petroleum Experts. This model predicts liquid drop out taking place in the tubing. The reservoir
gas gravity is determined using the principle of mass balance for an equivalent density of
the oil. The equations used are given in Appendix B.
5.4.1
Input Data
When Retrograde Condensate (Black oil) PVT is selected the following input data screen is
displayed:
Figure 5-18
Black Oil Condensate PVT
Enter the required data. Note if tank GOR and tank gas gravity are unknown, they can be
left at 0. The unmeasured tank gas rate should be estimated using a suitable correlation
and added to the separator gas. For such cases, the total produced GOR should be
entered under separator GOR. Condensate gravity is at standard conditions.
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If the separator pressure is above dew point, then there can be no liquid
production. When the dew point is unknown, set it to the reservoir pressure.
PROSPER handles conflicting input data by dropping the separator pressure to
atmospheric, and increasing the separator gas gravity as required to account for
the liquid production indicated by the Separator GOR. The mass balance is
respected at all times.
PROSPER uses produced CGR data for matching. To convert lab data in terms of
vaporised CGR to produced CGR, simply subtract the lab vaporised CGR data values from
the vaporised CGR at dew point. The following plot illustrates the process:
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CHAPTER 5 – PVT DATA INPUT
Figure 5-19
23 - 28
Vaporised vs Produced CGR
Produced vs Solution
CGR
Maximum vaporised CGR
100
90
CGR (bbl/MMscf)
80
70
60
50
40
Dew Point Pressure
30
20
10
0
0
500
1000
1500
2000
2500
3000
Pressure (psia)
Vapourised CGR
5.4.2
Produced CGR
Match Data
Please refer to the Match data in Section 5.2.3. The following fluid properties can be
matched to:
• Dew point
• Produced CGR (condensate to gas ratio, drop out CGR)
• Z (gas compressibility factor)
• Gas viscosity
• Gas FVF
The temperature and dew point must be entered for each set of match data. All other
operations are carried out as for Oil PVT. Refer to Section 5.2.4.
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The calculated PVT properties values should be matched to constant composition
expansion (CCE) data, which is corrected for the appropriate surface separation,
as this process best describes the evolution of the fluid in the tubing. Matching
the Z factor at dew point generally achieves good results.
Do not use Depletion Study CGR for matching tubing liquid dropout in PROSPER.
5.4.3
Calculations
Fluid property data can be calculated for a specified range of temperatures and pressures.
If the correlations have been matched, then the matched correlations will be used for the
calculations. Plots of fluid properties versus temperature or pressure can be generated.
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The calculated PVT properties values should be compared to constant
composition expansion (CCE) data, as this process best describes the evolution
of the fluid in the tubing.
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As calculated pressures (e.g. VLP) approach the convergence pressure, the
solution calculations slow down. This PVT method is only applicable below the
convergence pressure.
All other operations are carried out as for Oil PVT. Refer to Section 5.2.4.
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5.5
Equation Of State - All Fluids
This PVT option allows PROSPER to calculate the vapour fraction and fluid physical
properties using an equation of state (EOS) description for the reservoir fluid. The original
Peng-Robinson EOS is implemented in PROSPER. User EOS PVT modules can also be
linked to PROSPER. The PVT calculation method is identical for all reservoir fluid types (i.e.
oil and water, condensate or gas). The fluid type selected will affect the choice of IPR and
VLP models as well as the range of available sensitivity variables.
Equations of State were developed to give a mathematical relationship between pressure,
volume and temperature. They were originally put forward as a method of interpreting the
non-ideal nature of many pure substances. With time, this role has been extended
successfully to predicting the properties of simple and complex mixtures.
The equations used in PVT are derived from Van deer Waals Equation and in common
with it represent the total pressure as a summation of an attractive and a repulsive
element:
P total = P repulsive - P attractive
The classic Van der Waals equation describes this relationship as:
P = RT/(V-b) - a V2
where b represents the hard-sphere volume of the molecules and
a the intermolecular attraction.
In PROSPER we use the Peng-Robinson Equation of State model:
P = RT / (V-b) - a(T) / [V(V+b) + b(V-b)]
The PVT calculation method is identical for all reservoir fluid types (i.e. oil and water,
condensate or gas). Your choice of fluid type affects the choice of IPR and VLP models as
well as the range of available sensitivity variables.
A Note about using the EOS option
PROSPER can handle pressure drop calculations using EOS PVT in three distinct ways:
•
It can calculate fluid properties at each calculation step from the EOS explicitly.
This option eliminates any potential interpolation errors, as the EOS is used to
calculate fluid properties at the exact node pressure and temperature. The
additional computing overhead required by this method increases calculation times.
•
If PVT tables have been Generated, selecting the Use Generated Tables option
instructs PROSPER to look up and interpolate the tables. Provided the tables have
been calculated for sufficient points over the entire range of pressures and
temperatures required by the application, the error resulting from interpolation is
usually not significant. For problems that require it, the Use Tables option allows an
EOS fluid description to be used without significantly increasing computation times.
With the availability of faster computers, this option is not often used.
•
It can interpolate from imported tables. This is computationally much quicker but
there is a potential for interpolation errors.
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CHAPTER 5 – PVT DATA INPUT
Â
25 - 28
PROSPER will determine whether the reservoir fluid is an oil or a gas condensate
within the EOS PVT calculations. Since the VLP correlations are approached
differently depending on whether a gas or oil is being produced, calculations will
not proceed unless the fluid type detected by the EOS agrees with that selected
on the Options screen.
PROSPER can also use volume shift in its calculations.
A sample EOS PVT input screen is shown below:
Figure 5-20
Equation of State PVT
This screen requires input of pseudo component concentrations and properties (critical
temperature, pressure and volume, acentric factor, molecular weight and specific gravity).
Up to 30 pseudo components can be entered. Entry of Critical Volume, Volume Shift,
Boiling Point Temperature and Parachor are optional. Use of regressed critical volume
data will improve the quality of calculated liquid viscosities. Where critical volume data is
unavailable, PROSPER uses a correlation to estimate the values. The Parachor is used for
surface tension calculation. Binary interaction components are entered on a screen similar
to that shown below by clicking on the BI coeffs button from the EOS input screen.
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The user is now able to select between Peng Robinson or Soave-Redlich-Kwong
equations.
Also be able to export the values to PVTp creating a *.prp format file.
The parameters Omega A and Omega B can be entered or estimated using the
Fill in table button.
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Figure 5-21
Binary Interaction
Coefficients Input
After entering the interaction coefficients, click OK to return to the input screen. Then click
Generate to display a screen requesting the range of pressures and temperatures and the
number of pressure and temperature steps to calculate. If you are intending to use the
PVT table lookup option, ensure that the range of temperatures and pressures will span
that required by your application. A maximum of 1000 points are allowed in the calculated
PVT table. Next, click Calculate to access the EOS calculation screen:
Figure 5-22
EOS Calculation Screen
Calculate the PVT fluid properties using the EOS directly by clicking Calculate. Display the
results by clicking Plot. Click the Properties button and the program will determine the
equivalent black oil properties by flashing the fluid to atmospheric (i.e. standard) conditions
using the separator scheme entered in the main screen.
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CHAPTER 5 – PVT DATA INPUT
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Figure 5-23
Equivalent
Properties
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Black
Oil
Production rates entered when using EOS PVT assume the produced fluid is
flashed directly to atmosphere. e.g. for oil, enter the production rate that results in
the correct wellhead mass flow rate when the oil gravity is the same as shown by
the Properties calculation.
Once the PVT properties have been calculated, click OK to return to the input screen.
Now, a phase envelope can be displayed by clicking on the Phase Envelope button and
calculating the envelope. A sample phase envelope is shown below:
Figure 5-24
EOS Phase Envelope
PROSPER will automatically calculate the cricondentherm, cricondenbar and where
applicable, the critical point.
The EOS input screen allows pseudo component data to be imported directly from data
files such as those generated by Petroleum Experts' PVT package or other programs. Simply
click Import and select the appropriate file from the dialogue box. Once fluid properties
have been generated, they can be saved in a .PVT file by clicking the Save button and
entering a file name when prompted.
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Before importing PVT data, you must first ensure that PROSPER is using the
correct units for pressure and temperature.
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Â
The EOS option in PROSPER is not intended to be used as a fully featured PVT
package.
For maximum accuracy and computational efficiency, it is
recommended that compositional data be grouped and matched to lab data using
a program such as Petroleum Experts’ PVT Package and the resulting pseudocomponent properties used in PROSPER. The accuracy of well pressure loss
calculations depends on the accuracy of density predictions. Unless the EOS
densities have been carefully matched to lab data over a sufficient range of
temperatures and pressures, VLP calculations using EOS PVT will not be
accurate.
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The Gray VLP correlation’s internal PVT will over-ride the EOS PVT.
PETROLEUM EXPERTS LTD
6 Equipment Data Input
This section describes the menu option used to define the well's hardware, deviation
survey and flowing temperature profile. The program requests only the data required by
the Options that have been selected.
The data required for temperature prediction depends on the temperature model used. For
the Rough Approximation and Improved Approximation, there is little additional data
required. For the rigorous Enthalpy Balance temperature model, it is necessary to
completely define the well environment, including all casing strings, cement tops, formation
lithology etc.
A Note About Depth References .
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6.1
Depths in PROSPER for downhole and surface equipment are referenced to zero
on the deviation survey screen. Calculated pressures are then referenced to the
Xmas tree (if no surface equipment has been entered) or Manifold (if surface
equipment has been entered). Therefore, when PROSPER well models are
combined in a field-wide system model, the depth references that were used in
the individual PROSPER models are not important. In the field model, however,
the depth of each well's Top Node must be known with respect to a common
reference.
For subsea systems, any depth reference (e.g. sea level, drill floor, ground level)
can be used. If ground level is used, then a tied back well would have a negative
wellhead elevation. To minimise the potential for errors in correcting the depths,
it is recommended to use the same reference as used for the deviation survey
data.
Predicting Pressure Only
When predicting Pressure Only, click System  Equipment to display the following input
screen:
Figure 6-1
Equipment Input
To start data entry for a new application, click All  Edit. PROSPER will then display all the
relevant input screens in sequence. If data has already been entered, clicking the
Summary command button will display a summary of the current equipment. To go back
2 - 28
CHAPTER 6 - EQUIPMENT DATA INPUT
and edit one particular equipment item, click on the button beside the appropriate item. You
can enter data for the surface equipment and then include or exclude it temporarily from
any calculation by setting the “Disable Surface Equipment” choice box at the bottom of the
screen. To “Yes”
6.1.1
Deviation Survey
From the well deviation survey, select a few depth points that mark significant changes in
deviation. Enter pairs of data points for measured depth (MD) and the corresponding true
vertical depth (TVD). Up to 18 pairs of data points can be entered. The editing buttons
Cut, Copy, Paste, Insert and Delete operate on data records that have been selected by
clicking on their row number button(s). All records can be simultaneously selected by
clicking the All button. Use the Import button to import data from a wide variety of sources.
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There is a Measured Depth to True Vertical Depth (and the reverse is true) at the
bottom.
If the user wishes to find the TVD at a given MD, just enter the MD value in the
relevant space and hit on | Calculate. If the user wishes to find the MD at a given
TVD, just enter the TVD value in the relevant space and hit on | Calculate.
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3 - 28
Figure 6-2
Deviation Survey Input
Once depths have been entered, plot the well profile by clicking on the Plot command
button. A plot similar to the one below will be displayed:
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CHAPTER 6 - EQUIPMENT DATA INPUT
Figure 6-3
Well Deviation Plot
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The depth reference used by PROSPER for all subsequent calculations is zero in
the Deviation Survey table. The Deviation Survey table is interpolated to
determine the difference in TVD between any two well nodes. You have to enter
MD and TVD data at least as deep as the bottomhole - PROSPER will not
calculate beyond the last depth in the table. Deviation survey data entry is
required also for vertical wells - enter 0,0 for the surface reference and an MD the
same as the TVD of the intake node.
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The deviation survey has to start with 0 measured depth and 0 TVD. Due to this
reason, the reference depth (where TVD = 0) has to be at or above the wellhead.
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For subsea well (with or without pipeline), if the reference depth is selected in
such a way that it is above the wellhead (at the mean sea level for instance), we
can actually assume an imaginary vertical path in the deviation survey table
down to the wellhead. We do not need to include the pipeline measured depth in
the deviation survey. The deviation survey describes the deviation of the
downhole equipment only.
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Horizontal wells with deviation angles greater than 90 degrees from vertical can
be entered. PROSPER will issue a warning that the TVD of one node is less than
the previous one, but well profile plots and calculations will proceed as normal.
For Horizontal wells the deviation survey may be entered only up to the heel of
the well, as the well from the heel all the way up to the toe is a part of the inflow.
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CHAPTER 6 - EQUIPMENT DATA INPUT
6.1.2
5 - 28
Surface Equipment
The Surface Equipment screen is used to enter surface flowline and choke data on a
screen similar to the following:
Figure 6-4
Surface Equipment
Input
TVD, Length Format
PROSPER defines surface equipment as the pipe work between the production manifold
and the upstream side of the wellhead choke. The production manifold is regarded by
PROSPER as presenting a constant backpressure, regardless of flow rate. If systems
analysis is to be performed relative to the wellhead, (i.e. gathering system pressure losses
are neglected) then no surface equipment input is required.
The surface equipment model can be described using the following 2 elements:
•
•
Pipe
Choke
The manifold is set as the first equipment type automatically by PROSPER. Surface
equipment geometry can be entered either as pairs of X, Y co-ordinates relative to the
manifold or the Xmas Tree (Reverse X, Y) (Y co-ordinates deeper than the reference depth
are negative) or TVD of the upstream end and the length of the pipe segment. The
difference in TVD between the ends of a pipe segment is used to calculate gravity head
losses. The internal diameter (ID), roughness and pipe length entered determine the
friction pressure loss. The flowing temperatures for each upstream node must also be
entered when calculation Pressure Only.
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CHAPTER 6 - EQUIPMENT DATA INPUT
The Rate Multiplier column enables you to simulate the pressure drop due to several
identical wells being connected to a production manifold via a common surface flow line.
The fluid velocity in the flowline is multiplied by the value entered - thereby increasing the
frictional pressure losses. For most applications it should be left at its default value of 1.
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As an example, the pressure drop in a flowline connected to 3 identical wells
could be modelled using a pipeline rate multiplier of 3. 2 parallel flowlines having
identical dimensions can be modelled by entering the actual dimensions for one
pipe and a pipeline rate multiplier of 0.5. It is also possible to vary the rate
multiplier along the pipeline to simulate varying sections of dual pipelines for
example.
The editing buttons Cut, Copy, Paste, Insert and Delete operate on data records that have
been selected by clicking on their row number
button(s).
All records can be
simultaneously selected by clicking the All button. Use the Import button to import data
from a wide variety of sources. Up to 200 pipe segments can be entered, enabling the user
to model very long pipelines.
Figure 6-5
Surface Equipment Input
X,Y Co-ordinates Format
PROSPER’s multi-phase choke pressure loss correlation accounts for both critical and subcritical flow. We would recommend the use of the ELF Choke correlation that it similar to
the Petroleum Experts’ method but is more robust in extreme conditions.
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Ensure that the length of each pipe segment is equal to or greater than the
difference in TVD between its ends.
The downhole and surface equipment entries must describe a continuous
system. The TVD and temperature of the upstream end of the last pipeline
segment should be equal to the Xmas tree TVD and temperature. In X,Y coordinates, the Y co-ordinate of the last pipe segment must be the same elevation
as the wellhead TVD. (i.e. same magnitude, but opposite sign)
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To check that the surface equipment description is accurate, click Plot to display a plot of
the pipe elevation as follows:
Figure 6-6
Surface Equipment Input
Pipe Elevation Plot
6.1.3
Downhole Equipment
The Downhole Equipment screen enables you to describe the downhole tubing string.
Figure 6-7
Downhole
Equipment Input
The Downhole Equipment screen will change automatically depending on the options
selected in the Options menu screen. For example, if Annular Flow has been selected, the
tubing screen will require Casing I.D. and Tubing O.D. to be entered.
The tubing string can be modelled using the following element types:
•
•
Tubing
SSSV
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CHAPTER 6 - EQUIPMENT DATA INPUT
•
•
Restriction
Casing
PROSPER automatically inserts the Xmas tree as the first downhole equipment item. To
describe the tubing string, work from the shallowest depth downwards, entering the bottom
depth of changes in tubing diameter, ID and roughness factor.
Â
An SSSV is considered to have no length, and is modelled as a sharp-edged
orifice inserted between adjacent tubing string elements. A restriction is handled
identically to an SSSV. The pressure loss calculations in PROSPER account for
choking as sonic flow velocity is approached.
Casing is treated the same as tubing for pressure drop calculations. Downhole equipment
details should be entered down to the producing interval being analysed. The deepest
depth entries for the tubing, deviation survey and temperature should all be consistent.
Â
Below the uppermost producing perforation, the flow profile (as measured by a
production logging tool) depends on layer productivity etc. The uppermost
producing perforation is the deepest point in the well passing 100% of the
production. Below this point, the calculated frictional pressure gradient may be
over-estimated in high rate wells having small I.D. completions.
To select tubing string elements to build up the tubing string description, click on the list
box arrows to the right of the item fields and make your selection from the drop-down list.
The editing buttons Cut, Copy, Paste, Insert and Delete operate on data records that have
been selected by clicking on their row number
button(s).
All records can be
simultaneously selected by clicking the All button. Use the Import button to import data
from a wide variety of sources. Up to 18 tubing string elements can be input. For complex
completions, simplify the data entry by entering only the major elements that dominate the
overall tubing pressure drop.
The Rate Multiplier column enables you to simulate the pressure drop due to intermittent
sections of dual completion. The fluid velocity in the tubing is multiplied by the value
entered - thereby increasing the frictional pressure losses. For standard single tubing
completions it should be left at its default value of 1.
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6.1.4
9 - 28
Temperature Survey
This screen enables you to enter the flowing temperature profile of the well. If no bottom
hole flowing pressure survey data is available, the static reservoir temperature at the midpoint of perforations and the wellhead flowing temperature can be used. A minimum of two
depth / temperature points is required.
Figure 6-8
Temperature Survey
The editing buttons Cut, Copy, Paste, Insert and Delete operate on data records that have
been selected by clicking on their row number
button(s).
All records can be
simultaneously selected by clicking the All button. Use the Import button to import data
from a wide variety of sources.
Â
PROSPER interpolates temperatures from the survey data for depths within the
table limits, and uses linear extrapolation elsewhere. To eliminate potential
errors, ensure that a temperature is entered for the deepest node depth. It is
recommended that the maximum temperature survey depth, deviation survey
depth and intake node depths are all consistent.
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6.1.5
Summary
Before leaving the System  Equipment screen, the accuracy of the equipment description
should be checked by making an equipment summary. Click Summary to display the
summary screen.
Figure 6-9
System Summary
A sketch of the surface or downhole equipment can be drawn by clicking the appropriate
button from the Summary screen. Click Draw Downhole to display a sketch similar to the
following:
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Figure 6-10
Downhole Drawing
6.2
Predicting Pressure and Temperature (Enthalpy Balance)
To commence data entry for a new application, click All  Edit. PROSPER will then display
all the input screens in sequence. If data has already been entered, clicking the Summary
command button will display a summary of the current equipment. To go back and edit
one particular equipment item, click the button on the left of the appropriate item.
Figure 6-11
Enthalpy Balance
Equipment Input
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6.2.1
Deviation Survey
See Section 6.1.1 Deviation Survey
6.2.2
Surface Environment
Surface Environment is required for the calculations of heat loss for surface flow lines and
well risers. Data must be entered according to the screens shown below depending on
whether prediction is being done offshore or on land.
Figure 6-12
Surface Environment Input
(Off Shore)
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6.2.3
13 - 28
Drilling and Completion
This data is used to calculate the heat transfer coefficients down hole. If the offshore
option has been selected, the marine riser parameters must be entered in this section.
Entries must be from TOP to BOTTOM. Thus, the riser will be the first entry.
The screen below shows an offshore well with a 30" OD riser run to a seabed depth of 400
ft. The well also has a 7" OD liner run to 14000 ft with the liner top set at 11000 ft.
Figure 6-13
Drilling and
Completion Input
The completion fluid Liquid and Gas properties can have a significant effect on the heat
loss through the annulus. If pressure is maintained on the annulus, the mud weight used
should be modified to reflect the actual annulus pressure at the packer depth. If the well is
being gas lifted, the program assumes that the annulus is full of gas down to the injection
point.
The editing buttons Cut, Copy, Paste, Insert and Delete operate on data records that have
been selected by clicking on their row number button(s). All records can be simultaneously
selected by clicking the All button. Use the Import button to import data from a wide variety
of sources.
Â
Ensure the Tubing OD is less than the Casing ID.
For complex completions fluids, select the appropriate Customised option. This will enable
you to enter lookup tables for the required completion fluid properties. The screen below
shows the data that you will be required to enter.
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Figure 6-14
Customised
Completion Fluid
Lookup Table – data
entry
Up to five temperature dependent tables of properties can be entered. Please ensure that
the table will span the expected range of pressure- temperature conditions. The program
will not extrapolate outside the range of the input table. Use the Import button to import
data from a wide variety of sources.
6.2.4
Lithology
The program contains a database of thermal properties for various rock types including
Sandstone, Shale, Limestone, Dolomite, Halite and others. The thermal properties
database can be edited and added to as required. If detailed lithology data is available it
should be entered in the screen as shown below. If no data is available, use shale from
surface to total depth.
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Figure 6-15
Litho logy Input
The reservoir temperature and pressure should be entered for the production reference
depth. The formation temperature gradient is interpolated between the reservoir and
surface environment temperatures.
The editing buttons Cut, Copy, Paste, Insert and Delete operate on data records that have
been selected by clicking on their row number button(s). All records can be simultaneously
selected by clicking the All button. Use the Import button to import data from a wide variety
of sources.
Â
6.2.5
Thermal properties for buried pipelines are taken from the shallowest
formation type entered in the Litho logy screen.
Surface Equipment
An example of the surface equipment screen is shown below:
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Figure 6-16
Surface Equipment
Input
To calculate heat losses, additional data such as outside diameter, material type and
insulation (if used) are required to be input. The surface equipment model can utilise the
following equipment types:
•
•
•
•
•
Line pipe
Coated pipeline
Flexible tubes
User selected
Choke
To allow for pipe bends, etc., enter an equivalent length/diameter. The choke calculation
handles both sub-critical and critical flow. The program will calculate the temperature drop
across the choke. Descriptive labels for each element can be entered in the Label field if
desired. Labels appear on reports and calculation screens. Surface equipment geometry
can be optionally entered as TVD of the upstream end of the pipe segment and length or
as X, Y (from the manifold or the Xmas Tree) co-ordinate pairs. Refer to Section 6.1.2
above for more details.
The Rate Multiplier column enables you to simulate the pressure drop due to several wells
being connected to a production manifold via a common surface flow line. The fluid
velocity in the flowline is multiplied by the value entered - thereby increasing the frictional
pressure losses. For most applications it should be left at its default value of 1. As an
example, the pressure drop in a flowline connected to 3 identical wells could be modelled
using a pipeline rate multiplier of 3. 2 parallel flowlines having identical dimensions can be
modelled by entering the actual dimensions for one pipe and a pipeline rate multiplier of
0.5. It is also possible to vary the rate multiplier along the pipeline to simulate varying
sections of dual pipelines for example.
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The editing buttons Cut, Copy, Paste, Insert and Delete operate on data records that have
been selected by clicking on their row number button(s). All records can be simultaneously
selected by clicking the All button. Use the Import button to import data from a wide variety
of sources. Up to 200 pipe segments can be entered, enabling the user to model very long
pipelines.
Pipe insulation (e.g. concrete, foam or bitumen) can be modelled. To define the pipe
insulation click the Enter button to display the following screen:
Figure 6-17
Pipe Insulation Input
Select the required insulation type from the drop-down list, then enter the thickness. Enter
the insulation beginning with the innermost layer. PROSPER uses the thermal properties in
its database to calculate the thermal conductivity of the composite insulation. Click OK to
return to the surface equipment screen. Different insulations can be entered for each
section of the flowline as required. The calculated composite thermal conductivity is
referenced to the pipe inside diameter. Pipes can be laid on the surface (burial depth = 0)
or buried. The diagram below shows the burial depth geometry.
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Figure 6-18
Pipe Burial Depth
The burial depth is the distance between the soil surface and the bottom of the pipe
(including insulation, if present). The pipe is partially buried if the burial depth < O.D. of the
insulated pipe.
Â
Ensure that the flowline pipe geometry is consistent with the pipe burial depth. If
necessary, insert another node and change the burial depth for e.g. the riser.
Â
The soil conductivity around buried surface pipes is taken from the Thermal
Properties database for the shallowest rock type entered in the Litho logy screen.
In previous PROSPER releases, the soil conductivity was fixed at 3.5 W/m/K.
6.2.6
Downhole Equipment
The downhole equipment section is used to describe the production tubing, SSSV and
restrictions. The following equipment items are available:
•
•
•
•
•
Mild steel tubing
Plastic coated tubing
Stainless steel (either 13% or 25% chromium)
SSSV
Restrictions
The thermal properties database for downhole equipment elements can be edited or added
to if required. Pressure and temperature changes across subsurface safety valves and
restrictions (nipples) are correctly modelled. The following is an example of a downhole
equipment data input screen:
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Figure 6-19
Downhole
Equipment Input
For the Enthalpy Balance temperature model the casing dimensions and material type are
entered under Drilling and Completion, so the downhole equipment description is required
only for the tubing string.
To select tubing string elements to build up the tubing string description, click on the list
box arrows to the right of the item fields and make your selection from the drop-down list.
20 - 28 CHAPTER 6 - EQUIPMENT DATA INPUT
6.2.7
Databases
This optional feature is used to access the thermal properties databases for editing or
addition of user-defined materials. Select Databases and click Edit and the following
selection screen will be displayed:
Figure 6-20
Temperature Databases
Selection
Enter appropriate values for the Conductivity of cement and casing.
Depending on your selection, PROSPER expects input of thermal conductivity, emissivity,
specific heat capacity, specific gravity or density. An example of the Insulation Types
database screen is shown below:
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Figure 6-21
Insulation Properties Entry
Â
Check that you are using the correct units before entering the thermal properties.
Edited values remain in memory and become part of a particular well model file when the
file is saved. To permanently save edited values or new user-defined entries for use in
other projects, click the Save button to keep them in the database. The Reset button is
used to return all entries to their default values.
6.3
Rough Approximation
Equipment entry for the Rough Approximation temperature model varies little from the
Predicting Pressure Only option. Click on System  Equipment to display the following
input screen:
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Figure 6-22
System Equipment Input
To start data entry for a new application, click All  Edit. PROSPER will then display all the
relevant input screens in sequence. If data has already been entered, clicking the
Summary command button will display a summary of the current equipment. To go back
and edit one particular equipment item, click on the button beside the appropriate item. You
can enter data for the surface equipment and then include or exclude it temporarily from
any calculation by using the “Disable Surface Equipment” choice box at the bottom of the
screen.
6.3.1
Deviation Survey
Enter data as per Section 6.1.1
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6.3.2
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Surface Equipment
Surface Equipment is the same as for Predicting Pressure Only except for the requirement
to enter the temperature of the pipe surroundings and an overall heat transfer coefficient.
Figure 6-23
Surface
Equipment Input
The heat transfer coefficient should not be confused with the pipe thermal conductivity.
The overall heat transfer coefficient accounts for the heat flow through the production
tubing, annulus and insulation (if present) to the surroundings. Heat transfer by forced and
free convection, conduction and radiation must all be accounted for in the value of the
overall heat transfer coefficient. In PROSPER, the overall heat transfer coefficient is
referenced to the pipe inside diameter. Please refer to Section 6.1.2 for more details.
6.3.3
Downhole Equipment
The Downhole Equipment is the same as for Predicting Pressure Only. The casing
between the producing perforations and the tubing shoe is considered to be part of the
Downhole Equipment for the Rough Approximation temperature option. Therefore the
casing details should be entered in the Downhole Equipment. Please refer to Section 6.1.3
for more details.
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6.3.4
Geothermal Gradient
This is where the Rough Approximation temperature model differs most from the Pressure
Only case. PROSPER requires the formation temperature profile to be entered on this
screen:
Figure 6-24
Geothermal Gradient
Input
Â
Enter static formation temperatures from e.g. extrapolation of temperatures
recorded on logging runs - NOT flowing well bore temperatures.
As for surface equipment, enter an overall heat transfer coefficient that describes the
resistance to heat flow by all mechanisms (convection, radiation and conduction) from the
well to its surroundings. The Enthalpy Balance temperature model is a convenient way to
determine average heat transfer coefficients. The heat transfer area is referenced to the
pipe inside diameter.
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6.3.5
25 - 28
Average Heat Capacities
To edit Average Heat Capacities, click its check box then click Edit to display the following
dialogue:
Figure 6-25
Average Heat Capacities
Enter values that correspond to average conditions in your well. Note that for oil, and
especially gas that Cp values are strong functions of both temperature and pressure.
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6.4
The default values will often give reasonable results in moderate GOR oil wells.
However, actual Cp values for oil and gas vary widely. Do not rely on the
defaults - obtain good estimates of Cp, or use the Enthalpy Balance method
where accurate temperature prediction is required.
Improved Approximation
Equipment entry for the Improved Approximation temperature model varies little from the
Rough Approximation option. Click on System  Equipment to display the following input
screen:
Figure 6-26
System Equipment Input
(Improved
Approximation
Method)
To start data entry for a new application, click All  Edit. PROSPER will then display all the
relevant input screens in sequence. If data has already been entered, clicking the
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26 - 28 Chapter 6 - Equipment Data Input
Summary command button will display a summary of the current equipment. To go back
and edit one particular equipment item, click on the button beside the appropriate item. You
can enter data for the surface equipment and then include or exclude it temporarily from
any calculation by using the “Disable Surface Equipment” choice box at the bottom of the
screen.
6.4.1
Deviation Survey
Enter data as per Section 6.1.1
6.4.2
Surface Equipment
Surface Equipment is the same as for Predicting Pressure Only except for the requirement
to enter the temperature of the pipe surroundings and an overall heat transfer coefficient.
Figure 6-27
Surface
Equipment Input
The heat transfer coefficient can be specified for each pipe segment and should not be
confused with the pipe thermal conductivity. The heat transfer coefficient accounts for the
heat flow through the production tubing, annulus and insulation (if present) to the
surroundings. Heat transfer by forced and free convection, conduction and radiation must
all be accounted for in the value of the overall heat transfer coefficient. In PROSPER, the
overall heat transfer coefficient is referenced to the pipe inside diameter.
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6.4.3
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Downhole Equipment
The Downhole Equipment is the same as for Predicting Pressure Only. The casing
between the producing perforations and the tubing shoe is considered to be part of the
Downhole Equipment for the Improved Approximation temperature option. Therefore the
casing details should be entered in the Downhole Equipment. Please refer to Section 6.1.3
for more details.
6.4.4
Geothermal Gradient
PROSPER requires the formation temperature profile together with the heat transfer
coefficient to be entered on this screen:
Figure 6-28
Geothermal Gradient
Input
Â
Enter static formation temperatures from e.g. extrapolation of temperatures
recorded on logging runs - NOT flowing well bore temperatures.
As for surface equipment, enter an overall heat transfer coefficient that describes the
resistance to heat flow by all mechanisms (convection, radiation and conduction) from the
well to its surroundings. This value can vary throughout the formation. The Enthalpy
Balance temperature model is a convenient way to determine average heat transfer
coefficients. The heat transfer area is referenced to the pipe inside diameter.
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6.4.5
Sea Temperature Gradient
To edit Sea Temperature Gradient, click its check box then click Edit to display the
following dialogue:
Figure 6-29
Sea Temperature Gradient
Enter the data to describe to temperature gradient in the sea. Up to 20 points may be
entered. Use the Import button to retrieve the data from a wide variety of sources
PETROLEUM EXPERTS LTD
7 IPR Data Input
This section describes how PROSPER defines the reservoir inflow performance.
following table lists the Inflow Performance options:
IPR
Method
Back Pressure
C and n
Composite
Darcy
Dual Porosity
External Entry
Fetkovich
Forcheimer
Horizontal well - Bounded reservoir
Horizontal well - Const. Pres. upper
boundary
Horizontal well - dP friction
Horizontal well - transverse vertical
fractures
Hydraulically fractured
Jones
Multi-lateral
Multi-layer
Multi-layer - dP Loss
Multi-rate C and n
Multi-rate Fetkovich
Multi-rate Jones
Petroleum Experts
P.I. Entry
SkinAide
Thermally Induced Fracture
(injection only)
Transient
Vogel
7.1
Oil &
Water
Dry &
Wet Gas
9
9
Retrograde
Condensate
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
The
9
9
IPR Single Well Data Entry
The data for inflow performance models is entered using a single master screen. All the
sub-screens relevant to a set of model choices are accessible through clicking on buttons
on the main screen and on a tabbed interface in a data input screen. This means that data
for different models are entered concurrently and can be compared before selecting the
Calculate option. The generic features of the single well data entry screen are used in the
multilateral interface (see Section 7.8) for data entry to those network items with sufficiently
large data structures (namely tubing, completion and reservoir).
Click System  Inflow Performance in the main menu and the main data entry screen will
appear.
2 - 69
IPR DATA INPUT
7.1.1
The Main Data Entry Screen
The screen consists of three parts.
1. Section Buttons. At the top right of the dialog screen are two buttons, labelled Select
Model and Input Data. These allow switching between screens that control model
selection and detailed data input respectively. The former also contains data pertaining
to all models (such as reservoir pressure and temperature), and the latter manages the
data input specific to the models chosen. These buttons have the same function in the
multilateral data entry screens.
2. Action Buttons. To the left of the section buttons is a set of buttons that perform various
actions. Only the left-most group appears in the multilateral data entry screens.
3. Model Selection Screen. The child screen is the area below the action and section
buttons, and contains either the model selection or the data input screens. The same
occurs in the multilateral interface, although the actual model selection and data input
screens are different.
Figure 7-1
Main Data Entry
Screen
Section Buttons
As well as switching between the model selection and data input screens the section
buttons also indicate the validation status of the screens. The selection of one screen or
the other is shown by the indentation of the button for that screen and the validity of the
data is flagged by the colour. Green means that all the required data are entered and
within the numerical range for the units chosen; where appropriate, extra consistency
checks have also been carried out. Red implies that either there is insufficient data
entered or it is out of range/inconsistent. In addition, if no models at all are selected the
Select Model and Input Data buttons are marked invalid. Also, if not enough models are
selected the Select Model button is marked invalid (e.g. a reservoir but no skin model).
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Action Buttons
Done
This button exits the screen after saving and validating all the data pertaining to the chosen
models. If the data are not valid you are given the option of remaining in the IPR edit
screen and reviewing the validation errors, which are listed in a validation error dialog.
This also occurs after the validation in the Calculate, Transfer Data and Save Results
button commands. If you continue to exit with invalid data then all calculation options using
IPR data and models are disabled.
Cancel
This exits the screen and restores the data to its state at the start of the main edit session.
Validate
Checks the data on the current child screen for validity. If the data are not valid, the
validation dialog will appear with diagnostic messages.
Reset
This replaces the data of the current child screen with the data that was current when the
screen was entered.
Help
This displays information relevant to the current child screen.
Calculate
Saves and validates all the data pertaining to the chosen models (e.g. Darcy reservoir
model and Enter Skin By Hand) then runs the correct calculation routine if the data are
valid. On successful completion of the calculation the results are automatically plotted.
Plot
Will produce a plot screen appropriate to the current reservoir model (for example, a Darcy
plot) and plot the data from the last Calculate command.
Report
Enters the PROSPER Reporting System. The report produced will depend on the current
model choices. A fuller description of the reporting is found in Chapter 12.
Export
Can export current data (input and results) to the printer, a file, the clipboard or the screen.
It thus forms another method of reporting and is described more fully in Chapter 13.
Transfer Data
Saves and validates all the current data before opening a standard ‘File Save As’ dialog
that gives you an opportunity to save the data to file in the MBAL input format (.MIP).
Â
If PROSPER has been opened from a session in GAP then the data are posted to
GAP instead. The transfer button does not prompt for creation of a .MIP file.
Save Results
This option is only enabled when PROSPER is run from GAP. On a successful validation
you are presented with either the opportunity to over-write the current file or, if that is
refused, the PROSPER ‘File Save As’ dialog.
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IPR DATA INPUT
GAP
This option is only enabled when PROSPER is run from GAP. It shuts down the IPR screen
and minimises PROSPER, thus bringing GAP to the forefront.
Note that the ‘Save and Validate’ sequence carried out by several of the action
button commands does not actually save to file but transfers data from the
context of the IPR data screen to the PROSPER data structure in memory.
Hence, you should regularly save to file in order to avoid losing work due to
power failures or crashes.
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7.1.3
Model Selection Screen
An example of the model selection screen for the ‘Oil and Water’ fluid choice can be seen
in the screen dump of the main data screen (Figure 7.1).
This part of the IPR input screen controls the choice of almost all the tabbed dialogs that
will be seen in the subsequent data input screen.
There are four major selections done in this screen. These are:
•
Selection of Reservoir Inflow Model
o For each fluid various single well IPR models available are listed and the user
makes a selection.
•
Selection of mechanical/geometrical skin
o The user has the option of entering the skin by hand or using one of the
analytical models to model the completion skin.
•
Selection of deviation / partial penetration skin
o There are two skin models and these become available if a analytical skin model
of mechanical / geometric skin calculation has been used.
•
o
•
Reservoir input
The user also specifies the pressure, temperature, producing GOR and water cut
at this screen.
Relative permeability.
o This option can be set to Yes or No in case of oils. If set to Yes, the user has the
option of defining a set of relative permeability curves, which will be used to
change productivity of the system with changing water cut.
Â
The gravel pack selection and the type of completion (cased or open hole) are
chosen from the main Options screen (in the PROSPER main menu) but some
reservoir models have internal gravel pack data entries instead.
Â
In case gas coning option has been selected in main options, for oils the coning
button is displayed to allow the activation of a dialog screen in which parameters
for the calculation of rate-dependent GOR's can be entered
If the fluid is a gas or a condensate the format of the screen is very similar; only the
reservoir and other model input selections vary for example, in gas systems, we have CGR
and WGR instead of GOR and WC.
The choice of reservoir models governs which subsidiary models (principally skin) are
enabled. Thus, horizontal well models do not require a deviation skin data entry and some
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of the more complex reservoir models (e.g. multi-layer with dP friction loss) contain their
own skin and gravel pack models.
7.1.4
Data Input Screen
The data input screen contains a set of tabbed dialogs to allow you to enter all the data
required for calculation of an IPR, given a model set choice.
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Only one dialog is displayed at any one time, corresponding to the tab selected
as shown in Figure 7-2.
Figure 7-2
Data Input Screen
The tabs are labelled as follows:
•
•
•
•
•
Â
Reservoir Model
Mech/Geom Skin
Dev/PP Skin
Gravel Pack
Relative Perm
The tabs are coloured according to the validity of the data on the corresponding
dialogs.
•
If the tab is green, then the data are valid for the current system set-up.
•
If it is red, then the data are invalid or empty.
•
If the tab is grey, then this tab is not applicable to the current reservoir
model (or model selection) and so is inaccessible.
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Â
IPR DATA INPUT
The various screens as shown in the Figure 7-2, accessible by the bottom tabs
comprises the dialog screens, where the input parameters for the selection are
entered. laid in the area below the Section and Action buttons. In the case of the
model selection screen it is mainly occupied with ways of choosing models,
namely three list boxes, a drop-down list box and a push button.
For example Figure 7.2 shows a Darcy reservoir model dialog encapsulated in the data
input screen contained in the main entry screen.
• The Reservoir Model tab is marked invalid (due to the unlikely reservoir thickness of
–1 feet).
•
The Dev/PP Skin tab and relative permeability tabs are marked disabled. In this
case it is because the ‘Enter Skin By Hand’ option is selected which is assumed to
contain the deviation and partial penetration information. In the latter case relative
permeability is simply not selected (see Figure 7.1, showing the model selection
screen).
Notes on Data Validation:
Â
On each of the IPR Input screens there is a validate button. Pressing this button
invokes the a checking routine, which flags for the any invalid entries.
Notes on Data Entry in IPR section
In all the IPR input screens, for various options, the data may be required to be entered in
one of the following ways:
•
•
•
Â
Entering a value against a blank field as seen in all the entries of the Figure 7-2.
Pressing a push button, which takes us further into another screen, where actual
data required is entered as indicated against Dietz calculator on Figure 7-2.
Using a drop-down list.
Some models require data entered for multiple layers (e.g. multi-layer and multilayer with dP friction loss) and/or multiple completion zones (e.g. horizontal well
with dP friction loss and Wong-Clifford deviation/partial penetration model).
In dialogs with grid entry it is also possible to select, copy, cut and paste blocks
of the table, using mouse drag operations and the buttons provided on the
screen. As the data in a table are typically interdependent some consistency
validation checks are carried out in addition to the range validation.
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CHAPTER 7 – IPR DATA INPUT
7.2
7 - 69
IPR Models for Oil Wells
The model choice depends upon the available information and the type of sensitivities that
you wish to run. Some of the main highlights are
Â
There are twenty inflow options, including the multi-lateral method described in
Section 7.8, are available.
The average reservoir pressure and reservoir temperature must be entered for
all inflow performance models, except for multi-rate models.
From the Multi-rate models the average reservoir pressure can be back
calculated.
If test data is available it can be entered and plotted against the calculated
inflow.
Well skin can be either directly entered or calculated using the Locke, Macleod
or Karakas and Tariq methods for a mechanical/geometrical skin, and the
Cinco/Martin-Bronz or Wong-Clifford methods for a deviation/partial penetration
skin.
Relative permeability curves are optionally used together with fluid viscosities
(from PVT) to calculate the total fluid mobility for a given water cut. The
calculated IPR can be matched to measured data and used to calculate IPR
pressures for any rate and water cut. Relative permeability can be applied to all
oil IPR models in PROSPER.
Frictional pressure losses between multiple producing zones are accounted for
in the Horizontal Well - friction dP and Multi layer - friction dP. A network
algorithm determines the production from each zone while accounting for flowing
pressure losses to find the total well production.
These models can all be combined with gravel pack and relative permeability
models if the option is enabled (the former in the Options screen from the
PROSPER main menu and the latter from the IPR main data entry screen).
Once a specific model is chosen and data entered for it, after which an IPR can be
calculated using the Calculate button. The following sections list various inflow models that
are available for oil wells.
7.2.1
P.I. Entry
A straight line inflow model is used above the bubble point based on the equation shown
below. The Vogel empirical solution is used below the bubble point, the test point being the
rate calculated using the following equation at bottom hole pressure equal to bubble point.
The user input productivity index (PI) is used to calculate the IPR. P.I. Entry replaces the
Straight Line IPR in older releases of PROSPER.
Q = J ( Pr − Pb )
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PROSPER MANUAL
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IPR DATA INPUT
7.2.2
Vogel
The program uses the straight line inflow relationship above the bubble point and the Vogel
empirical solution below the bubble point. A single flowing bottom hole pressure and
surface test rate is used to calculate the IPR, below the bubble point. From this IPR the
rate and bubble point pressure are used to evaluate the PI for the straight line part of the
inflow above the bubble point.
When calculating IPR sensitivities for reservoir pressure, PROSPER retains the correct well
productivity.
Otherwise, changing the reservoir pressure changes the Vogel well
productivity.
Pwf
 Pwf
Q
= 1 − 0.2
− 0.8
Qmax
Pr
 Pr
7.2.3



2
Composite
This is an extension of the Vogel inflow solution (Petrobras method) that accounts for water
cut.
Vogel essentially decreases the inflow, below bubble point, because of gas formation.
However, if the water cut is higher, this effect of lowering the inflow should be lower. The
composite model captures this by using the following formulation.
J=
Q

Pwf
 Pwf
P 

− 0.8
Fo  Pr − Pb + b 1 − 0.2
1 .8 
Pr
 Pr





2

 + F {P − P }
w
r
wf


A test flow rate, flowing bottomhole pressure and water cut are required to be entered.
7.2.4
Darcy
The program uses the Darcy inflow equation above the bubble point and the Vogel solution
below the bubble point. Required input is:
•
•
•
•
•
Reservoir permeability (total permeability at the prevailing water cut and GOR)
Reservoir thickness (thickness of producing reservoir rock)
Drainage area
Well bore radius
Dietz shape factor (to account for the shape of the drainage area)
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CHAPTER 7 – IPR DATA INPUT
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7.2.5 Fetkovich
The Fetkovich equation for oil is a modified form of the Darcy equation, which allows for
two phase flow below the bubble point. The Fetkovich equation can be expressed as:
2
2
Q = J ( Pr − Pb ) + J ' ( Pr − Pwf )
Enter the same inputs as for the Darcy example plus the relative permeability for oil. Skin
can be entered either by hand or calculated using Locke's, Macleod's or the Karakas and
Tariq method.
7.2.6
Multi-rate Fetkovich
This method uses a non-linear regression to fit the Fetkovich model for up to 10 test points.
The model is expressed as:
Q = C (( Pr2 − Pwf2 ) / 1000) n
The fit values of C and n are posted on the IPR plot. If the reservoir pressure is not
available, the program will calculate it for you. For producing wells, enter a reservoir
pressure lower than the measured flowing bottomhole pressures. The program will dismiss
the reservoir pressure that has been entered and calculate it. For injection wells, input a
reservoir pressure higher than the test pressures entered. The program will then calculate
the reservoir pressure.
7.2.7
Jones
The Jones equation for oil is a modified form of the Darcy equation, which allows for both
Darcy and non-Darcy pressure drops. The Jones equation can be expressed in the form:
( Pr − Pwf ) = aQ 2 + bQ
Where "a" and "b" are calculated from reservoir properties or can be determined from a
multi-rate test. The same data as for the Darcy model plus the perforated interval is
required. Skin can be directly entered or calculated using the available methods.
7.2.8
Multi-rate Jones
This method uses a non-linear regression to fit For up to 10 test points for the Jones
model.
i.e.
( Pr − Pwf ) = aQ 2 + bQ
If reservoir pressure is to be calculated see Multi-rate Fetkovich above.
7.2.9
Transient
This IPR method takes into account the change of deliverability with time. This method can
be particularly important for tight reservoirs. Both the Darcy and Jones equations assume
that the well has reached pseudo-steady state flow conditions. In tight reservoirs, the
transient equation can be used to determine the inflow performance as a function of flowing
SEPTEMBER 2003
PROSPER MANUAL
10 - 69 IPR DATA INPUT
time. Once the flowing time is long enough for pseudo-steady state flow to develop within
the drainage radius, the Darcy inflow model is then used. Enter the same data as the
Darcy example plus:
•
•
Porosity
(Enter the reservoir porosity)
Time (Time in days, must be greater than 0.5 days)
The transient IPR equation is:
Pr − Pwf =

 ko t 
162.6 qo µ o Bo 
 Log 
2  − 3.23 + 0.87 S 
ko h
 φµ o Ct rw 


Time is the flowing time since the last reservoir pressure equalisation up to the time of the
analysis. If the flowing time exceeds TpSSS , the deliverability is evaluated using TpSSS , which
is equivalent to using the pseudo-steady state Darcy model.
7.2.10
Hydraulically Fractured Well
The hydraulically fractured well inflow model can be used to run sensitivities on hydraulic
fracture designs. The model is transient and is particularly useful in determining the
transient deliverability of a well after stimulation.
Â
Gravel packs can be combined with the hydraulically fractured well IPR to model
Frac-Packed wells
Required data input is:
•
•
•
•
•
•
•
•
•
Reservoir permeability (Total permeability)
Formation thickness
(Thickness of producing reservoir rock)
Drainage area
Well bore radius
Dietz shape factor
(Depends on the shape of the drainage area)
Time
(Inflow is transient in early time)
Fracture height
Fracture half length
Dimensionless fracture conductivity
7.2.11
Horizontal Well - No Flow Boundaries
This steady-state inflow model is based on the work of Kuckuk and Goode. It assumes
that the horizontal well is draining a closed rectangular drainage volume that is bounded by
sealing surfaces. The well can be placed anywhere within the drainage region. The
pressure drop along the well bore itself is not taken into account. This model may not be
suitable for long horizontal sections drilled in high productivity reservoirs. Horizontal well friction dP IPR should be used in such cases. Enter:
Â
•
The definitions of symbols for various parameters to PROSPER horizontal well
model are as per this manual and not necessarily on basis of the reference
paper.
Reservoir permeability
PETROLEUM EXPERTS LTD
(Total permeability at prevailing water cut)
CHAPTER 7 – IPR DATA INPUT
•
•
•
•
•
•
•
•
•
•
Reservoir thickness
Well bore radius
Horizontal anisotropy
11 - 69
(Thickness of producing reservoir rock h)
(Ratio of Ky/Kx where Kx is permeability in the
direction of the horizontal well and Ky is the
permeability perpendicular to the horizontal well)
Vertical anisotropy
(Ratio of Kz/Ky where Kz is the vertical permeability)
Length of well
(Horizontal section L)
Length of drainage area
(Reservoir dimension parallel to well Lx)
Width of drainage area
(Reservoir dimension perpendicular to well Ly)
Distance from length edge to centre of well
(Xw)
Distance from width edge to centre of well
(Yw)
Distance from bottom of reservoir to centre of well
(Zw)
A sketch outlining the main geometric parameters is shown below:
Figure 7-3
Horizontal Well Geometry
7.2.12
Horizontal Well - Constant Pressure Upper Boundary
The reservoir geometry is the same as for the No Flow Boundaries case, except for a
constant pressure upper boundary. The pressure drop along the well bore itself is not
taken into account. This model requires the same input data as the Horizontal Well Bounded Reservoir model above. The plot below compares PROSPER calculated IPR
values with those obtained by Kuckuk and Goode for a well in the centre of a 4000’ by
4000’ square reservoir.
PROSPER Horizontal Well IPR
vs Fine Grid Simulation
Figure 7-4
Horizontal Well P.I. vs
Well Length
35
Anisotropy
30
0.01
0.1
25
h = 50'
zw = 25'
rw = 0.25'
kh = 50 md
vis = 1 cp
P.I. (BOPD/psi)
1.0
20
Simulator - Lines
PROSPER - Symbols
15
4000'
4000'
10
5
0
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4
0.45
0.5
L1/2/Lx
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12 - 69 IPR DATA INPUT
7.2.13
Multi-Layer Inflow
The multi-layer inflow model allows up to 5 discrete reservoir layers to be entered as
shown in the following example input screen:
Figure 7-5
Multi-Layer IPR Input
Each layer can have different reservoir pressures, inflow models and fluid properties. The
oil gravity, GOR and water cut may be entered for each layer. The produced fluid
properties in the well bore are determined from the summation of the individual layer
contributions. The summation accounts for cross flow between layers having different
pressures. Each layer can be gravel packed if desired. Both Injectors and Producers can
be modelled. For cases where the zones are separated by a significant depth or friction
pressure losses are significant, the Multi-layer - dP Loss network IPR model should be
used.
Â
If PVT matching has been used in the PVT section, it is assumed that it was
performed on the commingled layer fluids. The fit parameters generated will be
applied to all PVT calculations for all layers in determining the combined inflow
performance.
To use the Multi-Layer IPR, enter the reservoir temperature, then click Input Data to enter
the tab controlled screen, and then click on the Reservoir Model tab button. For each
layer, select the inflow model from: Darcy, Multi-rate Jones, or PI Entry methods then enter
the layer PVT properties, average pressures, thickness and skins. For each layer, click the
Layer Data button and enter the information required by the inflow model.
Â
Â
To facilitate rapid comparison of flow rates using different completion options,
select a Null IPR type for a layer. This effectively turns the layer off. To return it
to production, re-select the original IPR type, and the layer parameters etc. will
be re-instated when the IPR is re-calculated.
The Multi-Layer IPR solves the combined contribution from each producing layer
at the intake node. This effectively places each layer at the same depth. The
reservoir pressure entered for each layer should therefore be referenced to the
intake node depth.
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CHAPTER 7 – IPR DATA INPUT
7.2.14
13 - 69
External Entry
This option allows an externally generated IPR data set to be imported or directly entered.
Up to five tables can be entered to allow sensitivities to be calculated on any arbitrary set
of variables. For example, IPRs for a range of reservoir pressures calculated by a
simulator could be input using this option.
An example of an external entry IPR input screen is shown below:
Figure 7-6
External Entry IPR
External IPR tables can also be imported from ASCII files. The file format is given in
Appendix E.
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PROSPER MANUAL
14 - 69 IPR DATA INPUT
7.2.15
Horizontal well - dP Friction
To adequately model horizontal well inflow in high permeability reservoirs, it is necessary to
account for pressure loss along the horizontal section. PROSPER divides the horizontal
section into up to 20 sections, and a network algorithm solves for zone production and well
bore pressure. Pressure loss between zones is accounted for. The Horizontal well - dP
Friction input screen is shown below:
Figure 7-7
Horizontal well - dP
Friction
The reservoir parameters entered in the upper section of the screen determine the overall
well productivity using the selected model. The zone parameters are used by the network
algorithm to re-scale the overall productivity zone by zone. A description of the input
parameters follows:
Reservoir Parameters
• Horizontal Well Model
• Reservoir permeability
• Reservoir thickness
• Well bore radius
• Horizontal anisotropy
•
•
•
•
•
•
•
Model used for overall well productivity)
(Total permeability at prevailing water cut)
(Thickness of producing reservoir rock h)
(Radius of open hole rw)
(Ratio of Ky/Kx where Kx is permeability in the
direction of the horizontal well and Ky is the
permeability perpendicular to the horizontal well)
Vertical anisotropy
(Ratio of Kz/Ky where Kz is the vertical permeability)
Length of well
(Horizontal section L)
Length of drainage area
(Reservoir dimension parallel to well Lx)
Width of drainage area
(Reservoir dimension perpendicular to well Ly)
Distance from length edge to centre of well
(Xw)
Distance from width edge to centre of well
(Yw)
Distance from bottom of reservoir to centre of well
(Zw)
The horizontal well models available are:
Kuckuk and Goode (bounded and constant pressure boundary)
Babu & Odeh
Goode / Wilkinson partial completion (bounded and constant pressure boundary)
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CHAPTER 7 – IPR DATA INPUT
15 - 69
The reservoir parameters are entered as for the original (infinite conductivity) horizontal
well model.
Â
Geometric definitions vary between published horizontal well inflow models.
Ensure that geometric parameters are entered in PROSPER are consistent with
the above definitions. Refer to the Horizontal Well IPR sketch for details.
Zone Parameters
Data for up to 20 zones can be entered. The required inputs are as follows:
•
•
•
•
•
•
•
Zone Type
(Blank, Perforated or Open Hole)
Skin method
(Enter by Hand, or Karakas & Tariq for perforated zones)
Gravel Pack
(Yes or No)
Zone Length
(Length of zone along the well)
Zone Permeability
(Average permeability at the prevailing water cut)
Flowing Radius (Internal diameter of well for calculation of friction pressure loss)
Zone Roughness
(Roughness for zone friction calculation)
These parameters describe the local permeability and the flow path along the well bore.
Click the Zone Data button to enter details such as skin and perforation parameters. If the
Skin Method is Enter by Hand, the skin and open hole radius are required. If Karakas &
Tariq is selected, then enter the perforation details as in Section 7.4.1 and PROSPER will
estimate the zone skin. If the zone is to be gravel packed, this data is entered under Zone
Data.
Â
To allow comparison of the IPR with and without friction losses, setting the zone
roughness to zero turns off the friction pressure drop calculation entirely rather
than calculating friction for a smooth pipe
Coning Calculations in Horizontal wells
The Ben Dikken and Chaperon correlations prediction of critical coning rates for gas, water
or gas and water have been implemented. From the Horizontal well - dP Friction data
entry screen click Coning to display the Coning Calculations screen:
Figure 7-8
Horizontal well Coning Calculations
Enter a production rate and porosity, then select the required coning calculation method.
Click Calculate to find the critical rate and time to breakthrough for the rate entered. The
SEPTEMBER 2003
PROSPER MANUAL
16 - 69 IPR DATA INPUT
pressure along the well bore for the specified rate is calculated and displayed by clicking
Plot.
Figure 7-9
Horizontal well - dP
Friction Loss Plot
The production contribution from each zone can be displayed as:
Rate per Unit Length
Percentage production
Cumulative percentage production
An example of a rate per unit length plot is shown below:
Figure 7-10
Horizontal well - Rate
per Unit Length
Â
The Horizontal Well - friction dP IPR models the pressure at the heel of the well
as a function of pressure. The intake node is therefore the heel of the well. The
heel should be the last node entered in System  Equipment and Deviation
Survey tables - it is not necessary to enter details of the horizontal producing
section except in the IPR.
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CHAPTER 7 – IPR DATA INPUT
7.2.16
17 - 69
Multi-Layer - dP Loss
This IPR is for modelling multi-layer reservoirs where friction pressure losses are
significant. PROSPER iterates until the production from each zone and the well pressures
converge at the solution rate. The effect of pressure drop between zones and cross flow is
accounted for. An example of a Multi-Layer - dP Loss input screen is shown below:
Figure 7-11
Multi-Layer Well- friction
Dp
This screen allows for the entry of up to 19 layers. To enter PVT, IPR data (permeability,
test rates etc. depending on the IPR model selected) and layer skin, click the appropriate
button to display the input screen. The depth entered for TOP is the depth for which the
IPR is to be evaluated. This is normally the same as the deepest depth entered in System
 Equipment, but it can be set to surface or other value.
The input data required are:
•
•
•
•
•
•
•
•
•
•
•
Layer Type
(Either Blank, Perforated or Open Hole)
Measured Depth (Measured depth of the bottom of layer n)
True Vertical Depth
(TVD of the bottom of layer n)
Layer Pressure
(Pressure at top of layer n)
Layer Flowing Radius
(Well radius for calculating inter layer pressure drops)
Layer IPR Model (Select from Darcy, Multi-rate Jones, P.I. Entry)
Layer Skin Model (Enter by Hand or Karakas & Tariq)
Layer Gravel Pack
(Yes or No)
Layer PVT Data
(GOR, Oil and Gas Gravity plus Water Cut)
Layer Parameters
(Relevant parameters for the selected IPR model)
Layer Skin
(Relevant parameters for the selected IPR model)
The IPR at surface can be calculated by entering the surface elevation for TOP depth and
a blank zone from surface to the shallowest producing zone. Use blank zones with
appropriate reduced I.D. to simulate the effect of sliding sleeves and flow controls in a
multi-zone completion. Click Calculate and the IPR for each layer and the summation will
be calculated and displayed on a plot as follows:
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PROSPER MANUAL
18 - 69 IPR DATA INPUT
Figure 7-12
Multi-Layer Well- friction
dP
To list the layer production in detail, click Results and scroll through the layer results one
by one. An example results screen is shown below:
Figure 7-13
Multi-Layer Well- friction
dP
Results
Gravel pack and well skin etc. can be seen by scrolling to the right of the results table.
Negative layer production rates indicate cross-flow into the layer.
Â
If a zero roughness is entered, then inter-layer pressure drops are not computed.
The layer pressures are then equivalent to a potential referred to the depth of the
TOP layer. The calculations are then equivalent to the simpler Multi-Layer IPR
without dP model.
Â
The multilayer option is now available for dry gas and gas condensate model
7.2.17
SkinAide
The Elf inflow and skin calculation method is incorporated in PROSPER. API perforation
characteristics can be used to estimate perforation damage given casing and formation
properties. A detailed description of SkinAide is given in Section 7.7.
PETROLEUM EXPERTS LTD
CHAPTER 7 – IPR DATA INPUT
7.2.18
19 - 69
Dual Porosity
This model is useful for naturally fractured reservoirs where the matrix (formation) porosity
is greater than the fracture porosity and the matrix permeability is much smaller than the
fracture permeability, but not negligible. It requires the entry of the following parameters:
fracture permeability, reservoir thickness, drainage area, well-bore radius, porosity, time,
storativity ratio and interporosity coefficient. The latter two parameters are defined as
follows:
1. Storativity ratio, ω = φf cf / ( φf cf + φm cm)
where φf is the fracture porosity, cf is the fracture compressibility, φm is the matrix porosity
and cm is the matrix compressibility.
2. Interporosity, λ = α km rew^2 /kf
where α is a shape factor (see Warren, J.E. and Root, P.J.: "The Behaviour of Naturally
Fractured Reservoirs.", SPE 426, SPEJ (Sept. 1963), 245-255.), km is matrix permeability,
rew^2 is effective well radius squared and kf is fracture permeability.
7.2.19
Horizontal Well with Transverse Vertical Fractures
This is for use with wells that are stimulated with one or more transverse vertical fractures.
It is assumed that the fractures are circular, the well goes through their centre and they are
evenly spaced. If there is one fracture it is in the middle of the well. The data to be
entered are the same as those for a horizontal well, along with the fracture half-length and
its dimensionless conductivity.
7.2.20
7.2.20.1
Thermally Induced Fracture Model
Overview
The algorithm follows the framework outlined in: SPE 30777, Thermally Induced Fractures:
A Field-Proven Analytical Model.
SPE Reservoir Evaluation & Engineering, February
1998. J-L. Detienne, Max Creusot, Nicolas Kessler, Bernard Sahuquet and J-L. Bergerot.
Information was also assembled from SPE 7964 (radial reservoir temperature profile) and
SPE 11332 (coefficient for thermo-elastic stress equation). Note that the temperature
profile derivation uses the same basis as the work of de Lauwerier referred to in SPE
30777.
SPE 7964: Analytical Definition of the Overall Heat Transfer Coefficient, A. B. Zolotukhin.
SPE 11332: The Effect of Thermo-elastic Stresses on Injection Well Fracturing, T.K.
Perkins and J.A. Gonzalez.
This model is concerned with the thermo-mechanical effects induced by injecting cold
water into a hot reservoir. The method first tests whether a calculated pwf rises above the
reservoir stress around the well bore. If this occurs then a fracture is assumed to
propagate and the pwf at the fracture tip is equated to the reservoir stress (i.e. equilibrium)
by iterating on the fracture length. The fracture’s effect is incorporated in a skin term, and
two stress effects are considered; a thermo-elastic one (varies with injection temperature)
and a poro-elastic one (varies with pwf). The stress at the wellbore is calculated by added
these effects to the initial reservoir stress. The pwf is calculated using varying fluid and
geometric properties (inner and outer radii) and a Darcy-like model in three circular zones.
The first (inner) is water that is still cool, the second is water that has warmed up, and the
third (outer) is the original reservoir.
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20 - 69 IPR DATA INPUT
The IPR calculated by this model consists, therefore, of two different zones with a breakpoint where the fracturing occurs. See the following figure.
Figure 7-14
Thermally Induced
Fracture IPR
The model is not valid for uncontrolled hydraulic fracturing where the fracture length may
be several hundred feet. The fracture should not extend beyond the so-called cooled
injection zone, the extent of which is calculated using the temperature profile referred to
above.
7.2.20.2
Data Entry
The Thermally Induced Fracture model reservoir data screen is split into two tabbed
screens, one handling 'Injecitivity Index' parameters, and one handling 'Thermomechanical' parameters. Also, it is required to enter the injected fluid temperature in the
model selection screen.
PVT parameter
Injected Fluid Temperature
Injectivity Index Parameters
Reservoir permeability
(Total permeability)
Formation thickness (Thickness of producing formations)
Drainage area
DIETZ shape factor
(Depends on the shape of the drainage area).
Wellbore radius
Porosity
(Enter the reservoir porosity)
Time
(Time in days, must be greater than 0.5 days)
Mean Historical Injection Rate
Thermo-mechanical Parameters
Initial Reservoir Stress
Sweep Efficiency
Injected Fluid Specific Heat Capacity
Overall Reservoir Conductivity
Overall Reservoir Specific Heat Capacity
Overall Reservoir Density
Top and Bottom Surroundings Conductivity
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Top and Bottom Surroundings Specific Heat Capacity
Top and Bottom Surroundings Density
Reservoir Thermal Expansion
(thermo-elastic correlating coefficient, relates
temperature perturbation to stress perturbation)
Biot's Constant (poro-elastic correlating coefficient, relates pressure perturbation to
stress perturbation)
Poisson's Ratio
Reservoir Young's Modulus
7.2.21
Using Relative Permeabilities in PROSPER
For oil well, the effects of changing relative permeability on the IPR can be taken into
account. From the model selection screen, select a suitable IPR method then enter the
reservoir temperature and pressure. If you do not need to consider relative permeability
effects, select No. To use relative permeability, select Yes.
If you have selected to use relative permeability, the PI will be corrected by multiplying the
ratio of the liquid mobilities. The liquid mobility is dependent on the water cut. Given the
relative permeability curves, they can be used together with fluid viscosity (PVT) to
calculate the total fluid mobility at different water cut.
The test water cut and the test reservoir pressure are used to determine the phase
saturations and viscosity at the original PI. With the use of relative permeability curves, the
liquid mobility at the test (reference point) can be calculated from:
M test =
K rw
µw
+
K ro
µo
The water saturation can always be estimated based on the relative permeability curve and
the water cut entered. At a particular reservoir pressure and water cut, the mobility (M) can
be calculated.
The corrected productivity index will be:
PI = PI test ×
M
M test
This value of corrected PI will be used to generate the IPR.
The possible reduction in liquid mobility due to any increase in the gas saturation is not
accounted for in this option. Hence, If you have selected to use relative permeability, there
is a further option to consider Vogel correction for GOR using the Standing Method
(Reference: K. E. Brown & H. Dale Beggs “ The technology of artificial lift methods” –
Volume 1). This correction takes into account the effect of increasing gas saturation on the
well PI. It requires the entry of a test GOR value. The GOR entered is taken as the total
produced GOR. Based on the PVT, then this used to calculate a free gas saturation Sg.
The Sw is calculated on basis of test water cut and test reservoir pressure. So is calculated
from
So = 1 − Sw − S g
Once the phase saturation and viscosities are known the PI is estimated from total liquid
mobility ratios as indicated above.
In case it is set to ‘No’
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PROSPER MANUAL
22 - 69 IPR DATA INPUT
The oil and water mobility values are calculated on basis of the assumption that the free
gas down hole is zero and the oil saturation. The oil saturation is calculated as
So = 1 − Sw
Based on these phase saturations, the PI correction is made.
After selecting the relative permeability option, we then go to the ‘Relative Permeability’
tabbed dialog in the data input screen. The child screen is shown in the following figure.
Figure 7-15
Relative Permeability Data
Input
Â
For Inflow Models like Darcy’s with a relative permeability correction, please
enter a water cut during test equal to 0, if the permeability entered in the
reservoir input data is true single phase permeability of the rock.
Enter the residual saturation, endpoint relative permeability and Corey exponent for both oil
and water. A Corey exponent of 1.0 defines straight line relative permeability curves.
Values greater than 1 give a concave upwards curve i.e. delayed water breakthrough.
Corey exponents less than 1 define a concave downwards relative permeability curve i.e.
early water breakthrough.
Matching measured and calculated IPR pressures establishes the well productivity for the
prevailing water cut. Click on Plot to bring up the following plot in the standard plot window.
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CHAPTER 7 – IPR DATA INPUT
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Figure 7-16
Relative
Permeability
Curves Display
To enter lab relative permeability, click Test Data to display the following screen:
Figure 7-17
Relative
Permeability
Test Data Input
Enter your test data and click OK to display the plot again. If necessary, adjust the values
of Corey exponents for oil and water until PROSPER's calculated relative permeability
curves fit the measured data points.
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24 - 69 IPR DATA INPUT
Having entered and verified the relative permeability data, click Finish to quit the plot.
Next, enter the necessary data for the particular IPR method selected and click on
Calculate to calculate and display a plot of the system IPR. The program automatically
calculates the well Absolute Open Flow Potential (AOF).
Figure 7-18
Example IPR Plot
To compare measured test pressures and calculated IPR pressures, click Test data and
enter rates and sandface pressures as on the following screen:
Figure 7-19
IPR - Test Data Entry
When relative permeability is being used, water cuts for both the test data and that used to
calculate the IPR curve are required. The water cut during test value will be carried over
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CHAPTER 7 – IPR DATA INPUT
25 - 69
from the relative permeability input screen. The water cut for calculation value can be
subsequently changed to evaluate the effect on the calculated IPR.
7.2.22
Coning Calculation
In addition to the coning model implemented for the Horizontal Well with dP Friction Loss
model, a gas coning option can be chosen from the Options screen in the main menu. This
applies to all oil IPR models. It modifies the solution GOR by multiplying it by a weighting
factor greater than 1, which is a positive function of the liquid rate. The output is a total, or
produced, GOR. The model implemented was originally developed for high permeability
reservoirs (see Urbanczyk, C.H, and Wattenbarger, R.A., "Optimization of Well Rates
under Gas Coning Conditions.", SPE Advanced Technology Series, Vol. 2, No. 2, April
1994).
The following data are required to calculate the total GOR from a rate:
•
•
•
•
•
Reservoir permeability
Perforation height (vertical distance from perforation top to bottom)
Vertical anisotropy
Vertical distance from perforation top to gas-oil contact
Three correlating parameters: F1, F3 and an exponent
If the gas coning is enabled then a Coning button appears on the model selection dialog
screen. Clicking on this brings up a dialog that allows the correlating parameters to be
tuned. There is an automatic matching facility, which calculates F3 from the other data and
a (rate, GOR) coordinate. Also, the GOR can be calculated from different rates whilst in
this screen in order to verify the parameters.
Â
It is recommended that this model be calibrated against measure rate versus
produced GOR data before using it as a predictive tool.
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7.3
IPR for Gas and Retrograde Condensate
Sixteen inflow options are available, including the multi-lateral one. The choice depends
upon the information available and the type of sensitivities that you wish to run. If multirate test data is available, the modelled IPR can be matched to the measured data.
As for oil, Gas inflow models are divided between design and production applications.
Calculated IPR models can be used to estimate productivity for different completion
options. Other models are available for estimating productivity from measured flowing
pressures.
The average reservoir pressure and reservoir temperature must be entered for all inflow
performance models, however both the Multi-rate C and n and Multi-rate Jones models can
be used to calculate the reservoir pressure from production test data.
7.3.1
Jones
The Jones equation for gas is a modified form of the Darcy equation, which allows for both
laminar and non-Darcy flow pressure drops. The Jones equation can be expressed in the
form:
( Pr2 − Pwf2 ) = aQ2 + bQ
Where "a" and "b" are calculated from reservoir properties or can be determined from a
multi-rate test. Required data entry is:
•
•
•
•
•
Reservoir permeability
Formation thickness
Drainage area
Wellbore radius
Dietz shape factor
7.3.2
(Total permeability)
(Thickness of producing reservoir rock)
(Depends on the shape of the drainage area)
Forcheimer
The Forcheimer equation expresses the inflow performance in terms of non-Darcy and
laminar pressure drop coefficients expressed as:
( Pr2 − Pwf2 ) = aQ2 + bQ
For "a" enter the non-Darcy pressure drop in drawdown2/(unit production)2 and for "b", the
laminar pressure drop as drawdown/unit production.
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CHAPTER 7 – IPR DATA INPUT
7.3.3
27 - 69
Back Pressure
In this form of the back pressure equation, C is determined from the reservoir pressure and
reservoir properties. Required input data are:
•
•
•
•
•
•
Reservoir permeability
Formation thickness
Drainage area
Wellbore radius
Dietz shape factor
Exponent n
7.3.4
(Total permeability)
(Thickness of producing reservoir rock)
(Open hole radius)
(Depends on the shape of the drainage area)
(Between 0.5 and 1)
C and n
This is the common form of the back pressure equation:
Q = C ( Pr2 − Pwf2 ) n
C and n can be determined from a plot of: Q versus (Pr2-Pwf2) on log-log paper. n is the
inverse of the slope and varies between 1 for Darcy flow to 0.5 for completely non-Darcy
flow. This option allows direct entry of C and n.
7.3.5
Multi-rate C and n
Up to 10 test points can be entered and they will be fitted to the C and n back pressure
equation for gas. The fit values of C and n are posted on the IPR plot and listed in the IPR
report. If the reservoir pressure is not available, the program will calculate it for you.
7.3.6
Multi-rate Jones
Up to 10 test points can be entered and they will be fitted to the Jones equation for gas
expressed as:
( Pr2 − Pwf2 ) = aQ2 + bQ
The fit values of a and b are posted on the IPR plot and listed in the IPR report. The multirate Jones IPR is a convenient way to determine a and b from well tests. These values
can be entered in the Forcheimer IPR for calculating IPR sensitivities.
If the reservoir pressure is not available, the program will calculate it for you. For producing
wells, input a reservoir pressure lower than the measured pressures. The program will
dismiss the reservoir pressure entered and calculate one. For injection wells, input a
reservoir pressure higher than one of the pressures entered. The program will calculate
the reservoir pressure.
Â
Note for injection wells. If flow test data for a producer has been fitted, the well
will have the correct IPR if it is then converted to an injector.
7.3.7 External Entry
Refer to External Entry for Oil in Section 7.2.14.
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28 - 69 IPR DATA INPUT
7.3.8
Petroleum Experts
The Petroleum Experts inflow option uses a multi-phase pseudo pressure function to model the
reduction in well productivity resulting from increasing liquid saturation in condensate wells.
It assumes that no condensate banking occurs and that all the condensate that drops out is
produced. Transient effects on P.I. are accounted for.
Figure 7-20
Petroleum Experts IPR
The following data is required to be entered:
•
Reservoir permeability(Either total, or effective permeability at connate water
saturation)
•
Formation thickness
•
Drainage area
•
Dietz shape factor
•
Wellbore radius
•
Perforated interval
•
Porosity
•
Time
•
Connate water saturation
•
Permeability entered
•
Non-Darcy coefficient
(Thickness of producing reservoir rock)
(Depends on the shape of the drainage area)
(Open hole well radius)
(Average over producing section)
(Refer to Transient IPR for Oil - Section 7.2.9)
(Used in relative permeability calcs. - see below)
(Either total or effective at Swc)
(Enter by hand or PROSPER can calculate it)
The non-Darcy coefficient can be entered from a well test where available or calculated
using a correlation.
The following diagram illustrates how PROSPER treats total and effective permeability in the
Petroleum Experts IPR model:
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CHAPTER 7 – IPR DATA INPUT
Figure 7-21
29 - 69
PetroleumExperts IPR
Relative Permeability Method
Petroleum Experts
Relative Permeabilities
Relative Permeability
Krl
1
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0
Krg when effective permeability is entered
Krg'
Krg when total permeability is entered
Slc
0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
Liquid Saturation
The mass flow rate of each phase is directly proportional to its mobility (k/µ), Kr’s can be
determined using PVT and the surface production rates. This technique is used to
determine the reduction in productivity as a function of the produced liquid ratios. The
derivation of the technique and details of the equations used are given in Appendix C.
7.3.9
Hydraulically Fractured Well
Please refer to Hydraulically Fractured Wells in Section 7.2.10. Additional input data for
gas and condensate applications are connate water saturation, a non-Darcy flow factor and
either relative permeability to gas or total permeability.
7.3.10
Horizontal Well - No-Flow Boundaries
Please refer to Horizontal Wells in Section 7.2.11. Additional input data for gas and
condensate applications are connate water saturation, a non-Darcy flow factor and either
relative permeability to gas or total permeability.
7.3.11
Multi-layer Inflow
The multi-layer inflow model allows up to 5 discrete reservoir layers to be entered each
with different reservoir pressures, inflow models and fluid properties. Each layer can be
gravel packed if desired. Both Injectors and Producers can be modelled.
The gas gravity, CGR and WGR must be entered for each layer. The produced fluid in the
well bore is equivalent to the summation of the individual layer contributions. Refer to
Multi-layer Inflow for Oil for more details in Section 7.2.13.
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30 - 69 IPR DATA INPUT
7.3.12
Horizontal Well - dP Friction
Refer to Horizontal Well - dP Friction for Oil. For Gas, PROSPER uses the Petroleum Experts
IPR method for steady-state flow. The Reservoir porosity and connate water saturation are
required to be input in addition to the parameters described in the Oil IPR section 7.2.15.
7.3.13
Dual Porosity
Please refer to Dual Porosity in the IPR for Oil section 7.2.18. Additional input data for gas
and condensate applications are connate water saturation, a non-Darcy flow factor and
either relative permeability to gas or total permeability.
7.3.14
Horizontal Well with Transverse Vertical Fractures
Please refer to Horizontal Well with Transverse Vertical Fractures in the IPR for Oil section
7.2.19. Additional input data for gas and condensate applications are connate water
saturation, a non-Darcy flow factor and either relative permeability to gas or total
permeability.
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7.4
31 - 69
Skin Models
PROSPER divides the total skin into two parts. These are:
•
•
Mechanical / Geometric Skin.
Deviation / Partial Penetration
The skin values could be either:
•
•
Entered by Hand
Calculated Using Models.
7.4.1
Mechanical/Geometrical Skin
Enter Skin by Hand
If a reliable skin value is available from transient well testing, then this value should be
directly entered by selecting the "Enter by hand" option.
Â
It is assumed that this value will contain deviation and partial penetration
information.
In case the entered skin is only mechanical skin, there is an option of enabling
the Wang and Clifford model for deviation and partial penetration in the input
screen for the skin itself.
Skin Evaluation using Models
PROSPER provides 3 methods of estimating a mechanical/geometrical skin factor using
input parameters such as perforation geometry, depth of damage etc.
The skin estimation models provided in PROSPER are those of:
•
•
•
Locke
McLeod
Karakas and Tariq
The required input parameters are often difficult to accurately define, therefore the absolute
value of the calculated skin often cannot be precisely predicted. The power of these
techniques is their ability to assess the relative importance of completion options on the
overall value of well skin.
The Elf SkinAide inflow method can also be used to estimate skin pressure drops for
cased- and open-hole completions with and without gravel packs.
PROSPER can also be used to estimate the value of the skin pressure drop across the
completion and the proportion of the total pressure drop attributable to the various
completion elements.
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32 - 69 IPR DATA INPUT
Karakas and Tariq has been found to give good results in many field applications. The
following input data are required:
•
•
•
•
•
•
•
•
•
•
•
Reservoir permeability
Perforation diameter
Shots per foot
Perforation length
Damaged zone thickness
Damaged zone permeability
Crushed zone thickness
Crushed zone permeability
Shot phasing
Vertical permeability
Wellbore radius
(Effective permeability at connate water saturation)
(Entry hole diameter)
(Effective perf. length in formation)
(Thickness of invasion)
(Permeability in invaded zone)
(Crushing associated with perforation)
(Reduced permeability near perf. tunnel)
(Enter the open hole radius, not casing I.D.)
An example of the input data for the Karakas and Tariq method is shown below:
Figure 7-22
Karakas and Tariq Skin
Input
A sketch outlining the main geometric variables is shown below:
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CHAPTER 7 – IPR DATA INPUT
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Figure 7-23
Perforation Geometry
Terms
Enter the requested data and, having entered some reservoir model data, press Calculate
to display an IPR plot. The plot shows the pressure drop resulting from the total skin as
well a breakdown of the individual factors contributing to the total skin as per the following
example. The individual factors to be plotted can be chosen from the Variables menu
option of the plot window.
Figure 7-24
IPR Plot
This plot is useful to assess the efficiency of a particular perforating program by allowing
the user to instantly assess the completion pressure loss resulting from different
perforation options. For gravel packed wells, the value of skin posted on the plot does not
include the gravel pack skin. Click Results on the IPR plot screen to display the
breakdown of dP's resulting from each completion element.
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34 - 69 IPR DATA INPUT
Â
Note on Skin:
Locke's technique is valid for shots per foot of 1,2,4,6,8,10,12,and 16.
7.4.2
Deviation/Partial Penetration Skin
Two models of this type are provided in PROSPER :
•
•
Cinco/Martin-Bronz
Wong-Clifford
The first requires the following data:
• Deviation angle of well
• Partial penetration fraction
• Formation vertical permeability
The second can compute a skin for multiple completions and requires the following data
entered:
1. Reservoir parameters:
• Formation vertical thickness
• Well-bore radius
• Drainage area
• Dietz shape factor
• Formation vertical permeability ratio
• Local vertical permeability ratio
• Horizontal distance from well to reservoir edge
• Depth of top of reservoir
2. Completion parameters – the following for each completion:
• Completion start measured depth
• Completion end measured depth
• Completion start true depth
• Completion end true depth
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CHAPTER 7 – IPR DATA INPUT
7.5
35 - 69
Gravel Packed Completions
PROSPER models gravel packed completions as a concentric cylinder having a user
specified permeability connected to the well bore via perforations of specified diameter. By
sensitising on perforation spacing and diameter, the effect of pressure drop due to flow
concentration on well performance can be investigated. Likewise, the effect of varying
gravel length (i.e. the thickness of gravel between the OD of the screen and the ID of the
original open hole) on skin can be evaluated. A sample gravel pack data input screen for a
cased hole is shown below:
Figure 7-25
Gravel Pack IPR Input
The following data input is required:
•
•
•
•
•
•
Gravel pack permeability
Perforation diameter
Shots per foot
Gravel pack length
Perforation interval
Perforation efficiency
(Enter the in-site permeability for the gravel)
(Diameter of perforation tunnel)
(Distance from the screen O.D. to the sandface)
(This affects the flow velocity in the perforations only)
(Proportion of perforations that are open and effective)
The main geometric parameters are shown on the following sketch:
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PROSPER MANUAL
36 - 69 IPR DATA INPUT
Figure 7-26
Gravel
Sketch
Pack
Geometry
CHAPTER 7 – IPR DATA INPUT
37 - 69
The PROSPER gravel pack model allows for non-Darcy (i.e. dP proportional to rate
squared) effects within the gravel pack and the resulting rate dependent skin. Lift curves
for gravel packed wells generated using PROSPER can be calculated from the sandface,
through the completion, and back to the production manifold. This more correctly models
the IPR as compared to simply imposing an additional skin to allow for the gravel pack
pressure loss as is done in many reservoir simulators.
Â
Gravel packs can be combined with the Hydraulically Fractured Well IPR to
model ‘Frac-Pack’ completions.
A summary of the main IPR equations is given in Appendix C.
7.6
Injection Wells
Irrespective of the inflow model used, Injection well IPR calculations are complicated by a
number of factors as compared to producers:
• Injected fluid temperature at the sandface is a function of surface temperature,
injection rate history and well configuration.
• Relative permeability to injected fluid is required.
• Injectivity changes with time as the fluid bank is pushed back away from the well.
• Fracturing (mechanical or thermally induced) often occurs.
Adequate results for injection well IPR can be obtained by reducing the reservoir
temperature on the IPR input screen to near the estimated sandface injection temperature.
The Enthalpy Balance temperature model can be used to estimate injected fluid
temperatures. PROSPER uses the reservoir pressure and temperature to estimate fluid
PVT properties in IPR calculations.
Most of the IPR pressure drop occurs near to the well. With this in mind, use an effective
permeability appropriate to your conditions. For empirical inflow models such as Vogel and
Multi-Rate methods, the effect of cold injection fluid viscosity is accounted for in the
pressure points. Changing the reservoir temperature will have no effect in these cases.
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38 - 69 IPR DATA INPUT
7.7
SkinAide
The SkinAide inflow method has been developed by Elf Aquamarine and
acknowledgement is given for its inclusion in PROSPER. The following description is based
on information provided by Elf.
7.7.1
SkinAide Theoretical Background
Consider the case of a partially penetrating, deviated well, cased and perforated and
equipped with a gravel pack. The total pressure drop around such a well corresponds to
the pressure difference between:
- an equipotential surface at the external limit of the reservoir drainage area, and
- another equipotential surface corresponding to the screen.
This total pressure drop is due to a number of features. Moving downstream from the
external limit of the drainage area towards the well:
- the position of the producing interval with respect to the reservoir geometry (due to
partial penetration and deviation).
- the damaged zone.
- interference between the different perforations.
- the crushed zone surrounding the perforation tunnels.
- gravel in the perforation tunnels.
- gravel in the annulus between the screen and the casing.
Pressure drops between equipotential surfaces can be added to one another, and the
conceptual model corresponds to an attempt to simplify the problem by finding
equipotential surfaces.
7.7.1.1
Position of the producing interval with respect to
reservoir geometry
The pressure drop due to the position of the producing interval with respect to the reservoir
geometry can be considered to be independent of the pressure drop surrounding the well
completion in so far as one can imagine an equipotential cylindrical surface with, say, a 2
m radius, separating the two regions.
Figure 7-28
SkinAide Equipotential
Surfaces
This pressure drop is calculated in SkinAide using a reservoir engineering correlation.
7.7.1.2
Interference between perforations and the damaged
zone
Moving downstream, the next feature encountered is the interference between perforations
and the damaged zone. If the perforation tunnel emerges from the damaged zone, the
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CHAPTER 7 – IPR DATA INPUT
39 - 69
damaged zone has much less influence than if the perforation remains entirely within the
damaged zone.
Figure 7-29
SkinAide Perforation
Interference
The pressure drop due to interference between perforations and the damaged zone is
calculated using the Karakas and Tariq correlation.
7.7.1.3
The Crushed Zone
The downstream limit of the previous feature is the crushed zone. The outside surface of
the crushed zone, and the inner surface of the perforation tunnel are both assumed to be
equipotentials. As a result flow in both the crushed-only and the crushed-and-damaged
zones is radial.
Figure 7-30
SkinAide Crushed Zone
Pressure drops in the crushed zone can be calculated analytically.
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PROSPER MANUAL
40 - 69 IPR DATA INPUT
7.7.1.4
Perforation tunnel which penetrates the formation
The next feature downstream is flow in that part of the perforation tunnel which penetrates
the formation. We use the flux into the tunnel previously calculated for radial flow in the
crushed zone to calculate the flow profile along the tunnel :
Figure 7-31
SkinAide
Perforation
within the Formation
This situation can be solved analytically.
7.7.1.5
Perforation tunnel through the casing and cement
Moving yet further downstream, two equipotentials can be drawn, one at the external
surface of the cement, the other on the inside of the casing:
Figure 7-32
SkinAide Perforation
Tunnel in Casing and
Cement
This linear flow can be solved analytically.
7.7.1.6
Annulus between Casing and Screen
The last feature is the region between the equipotential at the opening of the perforation
tunnel in the casing, and the screen.
Figure 7-33
SkinAide Perforation
Casing / Screen
Annulus
An approximate analytical solution has been found for flow in this region.
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CHAPTER 7 – IPR DATA INPUT
7.7.1.7
41 - 69
Hemispherical Flow Model
The conventional linear perforation model assumes that the surface of the perforation
tunnel is an equipotential surface. This assumption breaks down when permeability of
gravel in the tunnel becomes sufficiently low. When permeability in the tunnel becomes
sufficiently small, flow in the reservoir approaches hemispherical flow towards the
perforation mouth.
Figure 7-34
SkinAide Hemispherical
Flow
Flow takes place
- in the reservoir beyond the crushed and the damaged zones
- in the damaged zone
- in the crushed-and-damaged zone
- in the perforation tunnel itself.
Analytical solutions to hemispherical flow have been developed to represent this model,
which can be considered to be an upper bound to the conventional linear perforation
model.
7.7.2
Using SkinAide
When the SkinAide IPR model is selected, the following IPR Input screen is presented:
Figure 7-35
SkinAide Model
Options
Select the required options for the Flow and Skin models plus Perforation Data. The
options are listed below:
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42 - 69 IPR DATA INPUT
7.7.2.1
•
Flow Model
Steady State - corresponds to a constant flux at the outer reservoir boundary. The
inflow at the external boundary is equal to the well flow rate. This boundary condition
corresponds to pressure maintenance by natural (aquifer influx, gas cap drive) or
artificial (gas or water injection). The steady state productivity equation is:
PI steadystate =
2πkh


 re  1
 − + S
 rw  2

µB Ln

•
Semi Steady State - corresponds to no-flow at the outer reservoir boundary. This
boundary condition corresponds to reservoir depletion with no pressure maintenance.
The radial flow Productivity Index equation for semi-steady state is:
PI steadystate =
2πkh


 re  3
 − + S
 rw  4

µB Ln

These equations differ only in the constant 3/4 vs 1/2 for steady state flow. These radial
flow equations can be generalised for other drainage geometries.
Â
Pe, the static reservoir pressure is the average pressure in the well
drainage area, not the pressure at the external boundary. Pe is used in the
Productivity Index equation:
PI = Q / ( Pe − Pwf )
The reservoir pressure should be entered at the same reference datum as
the intake node depth.
7.7.2.2
Skin Model
•
Linear Flow - Skin pressure drop is calculated assuming that flow is predominantly
linear towards the well. This is the normal situation for a well completed across most of
the reservoir.
•
Hemispherical Flow - Skin pressure drop is calculated assuming a hemispherical flow
geometry. This situation occurs for single perforations or wells having extreme partial
completion effects.
•
Flow Giving Minimum dP - Skin pressure drop is calculated assuming flow is always
along the path of lowest resistance. (i.e. between linear and hemispherical flow)
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CHAPTER 7 – IPR DATA INPUT
7.7.2.3
43 - 69
Perforation Data
•
In-Situ Geometry Entered - The dimension of the actual perforations in the reservoir are
entered.
•
API Test Data Edition 4 - API perforation gun data are entered and SkinAide estimates
the downhole perforation geometry.
•
API Test Data Edition 5 - API perforation gun data are entered and SkinAide estimates
the downhole perforation geometry. This option utilises more recently defined gun test
specifications.
Having selected the required options, SkinAide requires data entry in the following
categories:
•
Geometry
•
Petrophysics
•
Damaged Zone
•
Cased Hole
•
Crushed Zone
•
Perforations
(Gun and perforation geometry)
•
Gravel Pack
(Only for Gravel Packed wells)
(Reservoir dimensions)
(Reservoir permeability etc.)
(Damaged zone properties)
(casing dimensions)
(Crushed zone properties)
The data required can vary according to the options selected. Click each data entry button
in turn and enter the data as follows:
7.7.2.4
•
Geometry
Reservoir Thickness - Enter the thickness normal to the bedding plane in dipping
reservoirs. When thin shales are distributed throughout a heterogeneous reservoir, use
the net sand thickness.
Figure 7-36
SkinAide Reservoir
Thickness
•
Completed Interval - Enter the perforated interval as measured along the wellbore.
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44 - 69 IPR DATA INPUT
Figure 7-37
SkinAide
Completion Geometry
•
Distance to Top of Completion - This parameter affects partial completion skin and is
measured along the wellbore. If gross sand thickness is used for reservoir thickness,
enter the actual distance to the top perforation (dimension h1 in the above sketch).
When using net sand, restrict the distance to net sand intervals.
•
Drainage Area - Area drained by the subject well
•
Dietz Shape Factor - Allows for drainage area shape and well placement.
Figure 7-38
SkinAide Drilled
Hole Diameter
•
Hole Diameter - Open hole drilled diameter. Use bit size or caliper measured size
where applicable. Perforation length, damage depth are measured beyond the hole
diameter.
•
Deviation - Average angle between the well axis and vertical.
Figure 7-39
SkinAide Deviation
Angle
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CHAPTER 7 – IPR DATA INPUT
7.7.2.5
•
45 - 69
Petrophysics
Horizontal Permeability - Reservoir permeability measured parallel to the cap rock
(along the bedding plane).
Figure 7-40
SkinAide
Horizontal
Permeability
•
Vertical Permeability - Reservoir permeability measured perpendicular to the horizontal
permeability in the vicinity of the completed interval. Used to determine anisotropy ratio
near the perforations. Values can be taken from core analysis.
•
Vertical Permeability for Geometrical Skin - Reservoir permeability for the bulk reservoir
measured perpendicular to the horizontal permeability. Determines the anisotropy ratio
between the completed interval and the remainder of the reservoir.
•
Porosity - Used in the high velocity flow coefficient correlation:
β = ak bφ c
Where:
k
φ
a,b,c
Reservoir horizontal permeability
Reservoir porosity
Constants
Correlations are used to estimate the values used in the high velocity flow equation.
Field specific correlations can be prepared from well test analysis.
•
Turbulence coefficient a - multiplier for the overall turbulence coefficient. Dimensions
are reciprocal distance.
•
Permeability exponent b - Permeability raised to this power. Default is -1.33. Note, the
exponent value entered corresponds to permeability in millidarcies regardless of the
current unit set.
•
Porosity exponent c - Porosity raised to this power. Default is 0.0. Note the exponent
value assumes the porosity is a fraction, regardless of the current unit set.
High velocity flow pressure drops arise from acceleration and deceleration of reservoir
fluids as they pass through pore throats as in the following diagram:
Figure 7-41
SkinAide Non-Darcy
Flow Pressure Loss
Mechanism
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7.7.2.6
Damaged Zone
The damaged zone is modelled as an annulus surrounding the wellbore in which
permeability and porosity have been impaired during the drilling and completion process.
The depth of damage is measured beyond the drilled hole.
In anisotropic reservoirs, formation damage is deeper in the low permeability direction than
the high permeability. An elliptic damaged zone forms in such cases. SkinAide assumes a
circular damaged zone irrespective of reservoir anisotropy.
Figure 7-42
SkinAide Damaged
Zone Geometry
•
Damaged Zone Thickness - Since damaged zone skin is controlled by the ratio of
perforation tunnel length to damaged zone depth, enter a damage zone depth that
respects this relationship.
•
Damaged Zone Permeability - Determines the ratio of damaged zone to reservoir
permeability. Estimating the true value is not straightforward, however, the undamaged
reservoir permeability could be used as a starting point.
•
Damaged Zone Porosity - Porosity to be used in the high velocity flow coefficient
correlation.
7.7.2.7
Cased Hole
The casing dimensions are used to correct the API perforation length for field conditions.
The casing I.D. is calculated from the O.D. and casing weight.
•
External Casing Diameter - Enter nominal casing diameter opposite the completed
interval.
•
Casing Weight - Enter nominal casing weight per unit length opposite the completed
interval.
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7.7.2.8
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Crushed Zone
Shaped charge perforating creates a cavity filled by charge debris and surrounded by a
zone of reservoir rock that has been altered by the high pressure / high temperature jet.
Charge debris is removed by perforation washing or underbalanced perforating - the
crushed zone remains. SkinAide recognises separate properties for the crushed zone in
the undisturbed reservoir and damaged zone.
Figure 7-43
SkinAide
Perforation Geometry
Most of the high velocity flow pressure loss occurs in the crushed zone and is added to the
loss in the reservoir. Note that if a zero crushed zone thickness is entered, no high flow
velocity pressure drops are calculated.
•
Crushed Zone Thickness - Thickness of perforation altered zone. The default value is
0.5 inches.
•
Crushed Zone Permeability - Reduced permeability for crushed zone within the virgin
reservoir.
•
Crushed Zone Porosity - Porosity in the crushed zone for estimation of high pressure
flow losses.
•
Crushed + Damaged Zone Permeability - Permeability for the crushed zone within the
damaged zone.
•
Crushed + Damaged Zone Porosity - Porosity for the crushed zone within the damaged
zone.
Permeability in the crushed and damaged zone is introduced by the ratio:
Rcrushed and damaged = Crushed and damaged zone (horizontal) permeability /
undisturbed
formation (horizontal) permeability.
The same anisotropy ratio opposite the completion interval as applies to the
undisturbed formation is used for the crushed and damaged zone permeability. It is
suggested that the crushed and damaged zone permeability ratio should be the
product:
Rcrushed and damaged = Rdamaged·Rcrushed only.
Where the ratio for the damaged zone:
Rdamaged = damaged (horizontal) permeability / undisturbed formation
(horizontal)
permeability
and the crushed-only zone:
Rcrushed only = only crushed zone (horizontal) permeability / undisturbed
formation (horizontal) permeability.
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Figure 7-44
SkinAide Perforation +
Damage Geometry
7.7.2.9
Perforations
The perforation data input depends on the option selected. If In-Situ Geometry is selected,
the actual perforation sizes are required. Alternatively, API test data can be entered for a
particular gun, and SkinAide will estimate the perforation geometry considering completion
and reservoir variables such as compressive strength and casing size.
Common Perforation Parameters
•
Perforation Efficiency - The number of producing perforations is the product of
perforation efficiency, shot density and the length of the completed interval. Perforation
efficiency is used to account for ineffective perforations such as those shot into shaly
beds. If gross sand is used to define reservoir geometry, the maximum perforation
efficiency should be the ratio of net/gross reservoir sand. If net sand is used, the
perforation efficiency does not need to be further modified.
•
Figure 7-45
SkinAide
Perforation Efficiency
•
Shot Density - Nominal shots per foot for the selected perforating gun.
•
Gun Phasing - Angle between two adjacent perforating charges. Affects interference
between perforation tunnels.
Figure 7-46
SkinAide Angle
Between
Vertical
Plane
and Perforations
•
Angle Between Vertical Plane and Perforations - For anisotropic reservoirs, the angle
between the perforation tunnels and the direction of maximum permeability influences
productivity. When 0° or 180° guns are selected, perforations are all aligned with the
low side of the hole. For other gun phasings, SkinAide assumes an angle of 45°.
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In-Situ Geometry Entered
•
Tunnel Length - Length of effective perforation in the reservoir formation i.e. beyond the
cement sheath.
Figure 7-47
SkinAide Perforation
Tunnel Geometry
•
Tunnel Diameter - Diameter of effective perforation in the reservoir formation.
•
Cavity Entrance Diameter - Not active - use Tunnel Diameter. SkinAide presently uses
a cylindrical model for perforations. Future versions will allow a cone-shaped
perforation geometry.
•
Cavity Tip Diameter - Not active - use Tunnel Diameter. SkinAide presently uses a
cylindrical model for perforations. Future versions will allow a cone-shaped perforation
geometry.
API Test Data
The correction from test data to In-Situ conditions is influenced by the API test series
selected. The form of data input is identical for both options.
•
API RP 43/2 Total Target Penetration - Length of perforation in Berea sandstone target.
If RP 43/2 data is unavailable, use 2/3 of API RP43/1 cement target TTP.
•
API RP 43/1 Entry Hole Diameter - Entry hole diameter for steel / cement target test.
Note that the steel quality changes between Editions 4 and 5 of the API test
specifications. Ensure the relevant data is entered.
Figure 7-48
SkinAide
Diameter
and Stand-off
Gun
•
Gun diameter - Gun diameter is used to correct API perforation test results for standoff.
•
Reservoir Uniaxial Compressive Strength - Compressive strength is used to calculate
in-situ perforation dimensions. Typical values of reservoir uniaxial compressive
strength are given in the following table:
Lithology
SEPTEMBER 2003
Reservoir
Compressive
(psi)
Uniaxial
Strength
(bar)
PROSPER MANUAL
50 - 69 IPR DATA INPUT
Loose sand
Sand which crumbles by hand
Sandstone from which sand grains can be peeled by
hand
Well cemented sandstone
Well cemented limestone
•
•
•
150
750
1500
10
50
100
3750
3750
250
250
Rock Density - Enter apparent In-Situ rock density as measured by a density log, not
the density of the minerals (e.g. Quartz) that comprise the formation grains.
Casing Elastic Limit - Used for correction of API data to In-situ perforation dimensions.
The elastic limit in thousands of psi corresponds to the pipe steel quality. e.g. N80
casing has an elastic limit stress of 80,000 psi.
Reservoir Stress - Used for correction of API data to In-situ perforation dimensions.
Stress is assumed to be Isotropic. Generally the minimum effective stress (frac
gradient) is suitable.
Gravel Packs in SkinAide
When the Gravel Pack option has been selected, additional data entry is required to
describe the pack geometry and properties. Separate gravel properties can be entered for
the annular gravel pack and the sand in the perforation tunnels. This allows mixing of
formation and pack sand to be simulated.
Figure 7-49
SkinAide Gravel
Pack Geometry
•
Screen Outside Diameter - The space between the screen O.D. and the drilled hole
diameter is occupied by gravel.
•
Annulus Gravel Permeability - Permeability of gravel in the space between the screen
and the open hole. Gravel size is specified in terms of mesh size. e.g. 20/40 mesh
gravel will pass a sieve with 1/20 inch holes, but not pass a 1/40 inch sieve. Average
laboratory measured permeability values for various gravel sizes are given in the
following table:
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Figure 7-51
SkinAide IPR dP Skin
Plot
Skin Components
The conceptual models used to calculate the total skin factor include :
- a contribution due to the position of the producing interval with respect to reservoir
geometry, called geometric skin Sgeometric
- contributions due to pressure losses close to the actual wellbore, beginning with
the pressure loss due to the damaged zone and ending with pressure loss in the
casing/screen annulus for gravel packed wells. This contribution to the total skin is
called the completion skin Scompletion.
The total skin is the sum of the two components
Stotal =Sgeometric + Scompletion
The contribution Scompletion to the total skin is particularly convenient when using reservoir
engineering equations. However Scompletion does not necessarily reflect the quality of the
completion itself. Indeed, imagine two wells with identical completions, producing
reservoirs with identical properties, the thickness of one reservoir is double that of the
other:
Figure 7-52
SkinAide Completion
Skin
Scompletion = a k h DPcompletion / ( Q m B )
Since DPcompletion is identical but reservoir thickness h differs by a factor 2, applying the
above relation leads to values of Scompletion, which differ, by a factor 2.
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Mechanical skins are defined so as to reflect the quality of well completion. In the formula
for mechanical skins, the vertical reservoir thickness h is replaced by the length of the
producing interval (measured along the wellbore) hp :
Smechanical = a k hp DPskin / ( Q m B )
where, for oil wells,
a
k
hp
DPskin
Q
m
B
depends on units
permeability
length of the completed interval
DPreal well - DPidealized well
flowrate (standard conditions)
viscosity (reservoir conditions)
fluid formation volume factor
SI
2π
m2
m
Pa
m3/s
Pa.s
v/v
US
7.07 10-3
mD
ft
psi
bpd
cP
v/v
French
0.0536
mD
m
bar
m3/d
cP
v/v
Total and mechanical skins are related by the simple formula :
Smechanical / hp = Scompletion / h
7.8
Multi-Lateral Interface
7.8.1
7.8.1.1
Network Interface
Motivation
Multilateral wells are different than single wells because they have a variable structure.
Both the number of branches and the way that they are connected is variable. Hence, a
flexible network data structure is appropriate for modelling these wells. Furthermore, to
provide a consistency with other Petroleum Experts products the interface has the same look
54 - 69 IPR DATA INPUT
Menu bar and tool bar
System
Visualisation windows
Navigator
Figure 7-53: The Multi-lateral Interface Main Window
Four main components of the interface are identified, as indicated on the diagram above,
which are described in more detail in the following sections:
1. Network window – the window on which the system network is drawn.
2. Navigator window – contains a full schematic that can be used to help navigation about
large systems.
3. Menu bar and toolbar. The menu bar is used for issuing commands to PROSPER and
the interface; it contains an abridged set of commands compared to a normal
application framework window because it is a subsidiary window of the main
programme.
The toolbar contains menu accelerators, icons for selecting and
manipulating network nodes and links, and icons for zooming or unzooming on the
network window.
4. Visualisation screen – up to three windows showing front, side and top views of the
multilateral network.
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Network Window
The network window is the main window on which the multilateral network is displayed and
manipulated. More than one network window can be displayed at one time; this means that
different views of the same system are available simultaneously, which can be of help in
editing large networks.
The system window is used to draw, edit, and view the system. The network nodes are
represented by coloured icons. The different actions that can be performed on this window
are obtained by clicking the right hand mouse button within the area of the system window,
which brings up a menu. Alternatively, the same set of actions can be performed using the
toolbar or the menu, which are described below.
Addition of Network Nodes and Links
To add an item to the system, activate the required network item type from the toolbar or
by using the right hand mouse button menu. The cursor will change to indicate that a
network item selection has been made. Click on the screen at the point at which you would
like the item to be inserted. A network node will be created and an icon to represent it. A
label dialog will appear prompting you to name the new network item. If you do not label
the item, a default label is provided, which can be over-ridden later using the icon right
hand mouse button menu.
Only the four left most items in the toolbar (tie-point, junction, completion and
tank/reservoir) are nodes: links, the fifth item, are added differently by dragging between
two nodes. Depending on a set of connection rules, the connection will be made or not
and the correct type of link will be chosen. For example, reservoirs can only be attached to
completions and the type of link is logical; in other cases the link is a piece of tubing.
These rules are reviewed in the description of toolbar items. The network is hierarchical
and arrows drawn on the links indicate the direction of the connections (which is normally
the same direction as increasing vertical depth). Each icon is given a characteristic colour,
depending on the network item it represents. The colours and items are: red (tie-point),
green (junction), yellow (completion), blue (reservoir) and pink (tubing).
Zoom/Unzoom
To zoom or unzoom, first select the appropriate icon from the toolbar or from the right hand
mouse menu, as described above. To zoom in on an area, hold the left hand mouse button
while sweeping the mouse cursor over the area in which you are interested. Alternatively,
you may click once at a point in the system, and the programme will zoom or unzoom on
that point using a fixed scaling factor (which may be adjusted using the Preferences dialog
in the Preferences menu).
To revert to a full system view at any time, double-click the left hand mouse button at any
point in the window (except on an icon). The view will re-scale to show the whole of the
system.
Mask/Unmask
To mask or unmask, first select the appropriate icon from the toolbar or from the right hand
mouse menu, as described above. To mask a node, click on itwith mask selected; to
unmask it click on it with unmask selected. Masking removes a node from the calculation
without removing it and its associated data from the network (which deleting does).
Masking is useful for simulating the effect of removing or adding in completions. Note that
masking a branch will have the effect of masking those below it in the hierarchy.
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Moving Items
Select the move option from the toolbar or from the right hand mouse menu. To move a
single item, place the mouse cursor above it and hold down the left mouse button while
dragging the mouse cursor to the desired new location. To move a group, select an area
as with the zoom option and then hold down the left mouse button with the mouse cursor in
the window before dragging the whole group to a new location. Items stay selected after a
group move but can be de-selected using the select option.
Deletion of Items
Select the delete icon from the toolbar or from the right hand mouse menu. Groups of items
may be deleted by group-selecting them as above, but with the delete option chosen. NB:
deletion of a node deletes the data associated with it so this option should be used with
caution. To delete a pure (non data-carrying) link re-do it.
Selection of Items
To select an item or items, first choose the select icon from the toolbar or from the right
hand mouse menu. Click on the item you wish to select, and its colour will reverse
accordingly. Alternatively, group selections may be made by dragging the left hand mouse
button over an area. The select option is a toggle, so it can select or de-select items.
Group selections can be used to turn off the selection actioned by a group move.
Editing of Items
If a network item carries data it has an icon associated with it and can be edited by double
clicking on it provided that none of zoom/unzoom, move, delete or select are chosen.
Editing of network item data is covered in the section on Data Entry.
Right Hand Mouse Button Actions
Utility menus will appear when the right hand mouse button is clicked anywhere in the
system view. The normal menu appears when the button is clicked over an empty space. It
contains the commands to add and manipulate network items as well as commands to
bring up dialog screens to change fonts and icon sizes. If it is clicked over a network icon,
a shorter menu will appear with a number of network item specific functions, such as the
ability to change the icon size and label, and delete and select.
Panning
To move the view around the system, move the cursor close to the edge of the view in the
direction in which you would like to pan. The cursor will change to an arrow. Clicking the
left hand mouse button will move the system view by a fixed amount depending on the
current scaling factor. To pan quickly, hold the mouse button down and, after a short time,
the pan action will 'auto-repeat'.
Popup Status Information
If no toolbar (or equivalent menu item) is chosen as you move the mouse over network
icons, a small window will appear. This contains basic status information for the node in
question and allows you to check, for example, the validity status of a network item without
entering the data entry screen. This is optional: to switch this function off go to the
Preferences screen. To ‘select nothing’, toggle the currently selected toolbar or menu
items, or choose the blank option from the drop-down list box in the toolbar.
Changing Icon Sizes / System Fonts
These functions are also available from the right hand mouse menu. See the section on
menu details for more information.
Other Window Actions
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Minimise:
Click this button to minimise the window in the multilateral main
window.
Maximise:
Click this button to maximise the window to fill the multilateral main
window.
Close:
Click this button to remove the window from the workspace.
System menu:
This contains various functions allowing the window to be
maximised, minimised, moved, etc.
7.8.1.2.2
The Navigator Window
This window can be used to aid in navigation about a large system. It will always consist of
a system schematic that is independent of any zooming on a system window. In addition to
the network, it contains a tracking rectangle that encloses the portion of the system
currently under view in the system window.
The tracking rectangle has two functions. If the focus is currently on a network window, this
rectangle surrounds the area of the network that that view is displaying. Alternatively, the
rectangle may be used to create new views of the network if the navigator window is
currently in focus. When the mouse is moved over the rectangle, the cursor changes to
allow you to stretch or resize the rectangle. In this way, you may move the window over an
area of the system of interest. Double-clicking the left hand mouse button in the area will
create a new system view displaying the area you have selected, although resized to
preserve a sensible aspect ratio.
Right Hand Mouse Button Menu
Clicking the right hand mouse button within the navigator window will produce a utility
menu. This contains the following functions:
Navigator On Top: By default, the navigator is always on top of all system views. This can
be changed by selecting this item from the menu.
Hide Window: The navigator can be hidden using this option and, once removed, will not
appear in subsequent sessions until reopened from the Window menu. The navigator can
also be hidden by clicking on the cross button at the top right hand corner of the window or
by using the Window menu option.
New Window: Another way of producing a new view (see above).
Icon Sizes: Invokes the Icon Sizes dialog (see below).
7.8.1.2.3
Toolbar Details
The toolbar is located below the main menu at the top of the main window. It consists of a
row of icons (described below) which act as accelerators to the menu functions accessed
from the Tools menu or most of those called from the right hand mouse button in the
network window.
The functions of the various buttons are described below. A quick description can be
gained for a given button by holding the mouse cursor over the button for a moment. A
small yellow box with a short description will appear.
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Network Item Set-up
The functionality of the network items buttons is duplicated in the drop-down list: a
selection from this list will cause the appropriate button on the toolbar to be shown as
depressed. When a network item button is selected, the cursor, when over a system
window, will be drawn to represent the current selection. Click once on the system window
to cause a new node of the required type to be created at the chosen point. A label dialog
will appear to allow you to label the node immediately; if you choose not to a default label is
created. This can be edited later by clicking the right hand mouse button on the icon
created.
Connections between nodes are created by choosing the ‘Link’ button and holding down
the mouse left hand button whilst dragging between two nodes. There is a connection
hierarchy, which is represented by the branching of a parent branch into one or more child
branches, in the same way that the multilateral well branches out physically. You indicate
the direction of the hierarchy for junction-completion or completion-completion connections
by the order in which they are joined up.
Tie-point. This is the node for which the IPR is solved and is located at the top
of the system (in vertical depth and hierarchically). Hence, the tie-point can
only be a start point.
Junction. The main purpose of the junction is to be a branching node. It can
only have one link into it (from a tie-point, completion or other junction) but any
number coming out.
Completion. This contains both tubing and completion information. It is
attached below a tie-point, junction or another completion. It can only have one
link into it and branches out to either a junction or another completion. It can
also be logically attached (no direction implied) to any number of reservoirs (but
at least one).
Tank/reservoir. This represents a reservoir source and is logically attached to
any number of completions (but at least one).
Link. Connecting to a junction, the link becomes a tubing node and contains
data. Going into a completion, the tubing information is in the completion and
the link is ‘blank’ only indicating the hierarchical relationship between the nodes
it connects with an arrow. Finally, when connecting a completion and a
reservoir, the link is logical and not hierarchical. Note that re-doing a link
between two nodes allows you to delete it.
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Network Manipulation
Zoom in/out. When 'zoom in/out' is selected, a zoom can be achieved either by
clicking the mouse on the system window, which will zoom in/out a fixed
amount and set the centre of the view to the position clicked. If ‘zoom in’ is
selected, sweeping an area with the mouse will zoom in on the area selected.
The aspect ratio will be retained when an area zoom is performed.
Mask/Unmask an item. After masking is selected specific items can be
removed from the network for calculation purposes without deleting them. This
is particularly useful for seeing the effect of removing a completion item.
Delete a node. After this is selected, you may delete a node by clicking on the
item in the system window. The icon automatically becomes unselected
following a deletion to prevent accidental deletion of further nodes. To delete a
pure (non data-carrying) link re-do it.
Move a node. After this is selected, a node may be moved by clicking on the
item in the system window and then, with the mouse button depressed,
dragging the item to the new position. A group of nodes may also be selected
and moved.
Select a node. After this is pressed, a node may be selected/de-selected by
clicking on the item in the system window. The item will reverse its colour to
indicate selection/de-selection.
7.8.1.2.5
Menu Details
Finish
Done – exits the screen but validates the multilateral structure and data first. If the
structure is not valid you are warned and given the chance to remain in the multilateral
screen. Otherwise, you can exit but the data are marked invalid.
Cancel – leaves the multilateral screen, restoring the network to its state at the start of the
edit session.
Tools
These are equivalent to items to the right of, and indeed inside, the drop-down list box in
the tool bar and have been explained above.
Analyse
This menu contains options to plot and report the IPR results in a similar way to those in
the Single Well IPR. The multi-lateral is treated as one reservoir model option, such as the
multi-layer with dP friction loss. There is also a Calculate option, which brings up the
dialog in the following figure.
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Figure 7-54
Multi-lateral
Calculation Dialog
The Calculate screen gives the option of calculating one IPR point or a curve. In the
former case you can choose to calculate pressure from a rate or rate from a pressure. In
the latter case, pressure is calculated for a range of rates up to the AOF, as with other IPR
calculations. From this screen it is possible to specify the number of IPR points (maximum
20) and the minimum pressure to calculate to. These are to help speed up calculations if
appropriate. Results of the points for curve calculation will be reported at the bottom
section of the screen. Also, having a bearing on calculation speed is the switch between
infinite and finite conductivity modes of calculation. In the latter case the pressure drop in
the tubing is taken into account. Before carrying out the calculation, the network structure
is validated and any errors are reported in the white list box in the middle section of the
screen. If the structure is not valid the calculation is not carried out. The Details button is
used to display pressure and rate-related parameters with respect to the measured and
vertical tubing depths of each branch.
During a calculation, diagnostic information is reported to the list box. Also, a Cancel
button is placed above the Calculate button to allow you to stop the calculation. The
buttons to the left of the list box perform the functions in the Analyse menu, except Help,
which brings up this section. The push button Done exits the screen.
Visualise
These items are dealt with in the section on visualisation screens.
Preferences
The preferences dialog is gained from the Preferences item of the frame window menu. It
allows you to customise a set of user-interface variables for subsequent PROSPER
sessions. The following options are available:
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•
Enable Flyover Status Information. If this is checked then you will see a status box
appear as you move the mouse over the network item icons.
•
Auto-repeat delay when panning. When you are panning you may hold the left-hand
mouse button down to ‘auto-repeat’ the action. The value given in this field represents
the time (in ms) before the auto-repeat action starts from when you click the mouse
button.
•
Fraction of screen to pan per click. This represents the ‘resolution’ of panning.
•
Zoom/unzoom factor. A single click in a system window while the zoom or unzoom
icons are active results in a fixed scaling to be applied to the view, while the centre of
the view is changed to the position in which the mouse was clicked. The value entered
in this field is the fixed scaling factor, and as such should be greater than one.
•
Background. You may change the bitmap that is displayed on the background of the
main window (by default this is a PE logo with contact information). Select the required
bitmap by pressing the button to the right of the field. The bitmap will not be loaded
immediately; you must shut down and restart the multilateral main screen.
Output
Printer Setup - to set up the printer if not already done.
Print - prints the current child window as a hard-copy, metafile or to the clipboard, whether
a network window or a visualisation screen.
Window Menu
• New Window. This creates a new system view. The new view is zoomed out to include
all the components.
• Close All. Shuts down all system windows in the application.
• Cascade. This reorganises the system windows into a ‘cascade’.
• Tile. Tiles the system windows.
• Toggle toolbar display. This will remove the toolbar if it is currently displayed, and viceversa. If the toolbar is not displayed, you can still access the toolbar commands from
the right hand mouse button on the system view window.
• Toggle navigator display. Displays or hides the navigator window.
Below this is a list of currently active system windows. You may focus onto a different
window to your current window by clicking on one of these.
Help
Brings up this information on the network interface.
Other Items
Apart from the preferences it is possible to change other aspects of the user interface:
namely font and icon sizes.
Network Fonts
You may change the fonts used in the network drawing. To do this, select the Fonts option
from the menu obtained following a right hand mouse button click in the system window.
This will bring up a font selection dialog. Select the font and style that you require and
press OK. The new font will be applied to all network drawings and also to labels in the
visualisation windows.
Icon Sizes
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The sizes of the icons used to represent the network nodes can be changed. Select the
Icon Sizes option from the menu obtained following a right hand mouse button click in the
system window. The following dialog will appear:
Figure 7-55
Icon Size Dialog
The dialog consists of a slider with a data entry field, which contains the current icon size
(this defaults to 50 out of an arbitrary 0 – 100 range for a new file). Change the icon size by
adjusting the slider or entering a new size in the entry field. Check the ‘Automatic Update’
box to update the system window with the new size as you move the slider.
When you have entered the new icon size, click on This View or All Views. In the latter
case the change will be applied to all network windows. In the former case, only the
currently active network view will be changed. The new icon size will not be saved; i.e. all
changes will be lost when the current file is exited.
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Visualisation Screens
These screens supply three 2-D views (front, side and top) of the 3-D multilateral object.
The salient visual objects (tie-points, junctions, tubing, completions and reservoirs) are
drawn symbolically but they are spaced to scale. The screens are updated whenever a
network item is edited and has a valid data set and whenever an item is deleted or
becomes invalid. The visualisation objects are given the same colour as their equivalent
network objects (e.g. blue for reservoirs), and are identified by the same labels as in the
network structure.
The geometry used is left-handed Cartesian. It is assumed that the positive x axis is along
the direction of zero azimuth, positive y is at 90 degrees and positive z is in the direction of
increasing depth. The front view shows the (x, z) plane, where y is increasing going into
the screen and consequently positive z corresponds to moving down the screen and
positive x corresponds to moving to the right. The side view shows the (y, z) plane, where
x increases coming out of the screen, z increases going down the screen and y increases
going to the right. The top view shows the (y, x) plane where z is increasing going into the
screen, x increases going down the screen and y increases going to the right.
The screens are brought up usin
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7.8.2
7.8.2.1
Data Entry
Overview
The data associated with any network item is accessed by double-clicking on its icon when
none of the network manipulation options (zoom/unzoom, delete, move and select) have
been chosen. This brings up a screen with editable data fields in it.
Apart from the tie-point and junction data screens, the main data entry screen for each
node is similar to that of the single well main data entry screen (see Section 7.1).
However, the reservoir data input child screen does not have any tab buttons in it. The
main data screens differ from the single well case in the action buttons: only the left-most
group - Done, Cancel, Reset, Validate and Help - are available. Their function is the same
as in the single well case. Hence, the differences between the single well IPR data entry
and the similar multilateral ones lie in the model selection and data input child screens.
Given the hierarchical nature of the network, editing a parent branch causes the starting
points (e.g. depths) of child branches to be initialised. Those data fields that are initialised
from outside a particular network item are set read-only (coloured cyan) when the screen to
edit that net item is brought up. Hence, in order to edit a net item and fill it with valid data it
is normally necessary to have edited the parent branch first. However, it is not a
requirement to edit the network in hierarchical order as any child net item can be filled with
invalid data and saved before editing its parent.
Another difference from the single well IPR is that in each screen, on the right hand side,
there is a list box containing a drawing of the network where the data carrying nodes are
sorted hierarchically, by type or alphabetically according to a right-hand mouse button
menu selection. By clicking on the line corresponding to a node the given screen is closed
and the screen belonging to the node clicked on is opened.
7.8.2.2
Tie-point and Junction Data
The tie-point data consist of a measured and vertical depth, with an implied azimuth of 0°.
The junction data are the same but are read-only. A junction must always be hierarchically
below another network item, so its data are entered automatically from its parent. As
mentioned earlier a junction mainly forms a branching point.
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7.8.2.3
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Tubing Data
Model Selection Screen
The model selection screen for tubing has options to select horizontal and vertical
correlations, choke models, flow types (tubing or annular), correlation thresholds, and a
well-bore radius. None of the options affect the general format of the data input screen but
the flow type affects the details of the equipment tabbed dialog in the data input screen.
Data Input Screen
There are two tabbed dialogs in this data input screen, which allow the entry of a deviation
survey and equipment descriptions. These dialogs contain tables very similar to the ones
encountered by selecting System | Equipment from the PROSPER main menu and then the
Deviation Survey and Downhole Equipment push buttons. In the case of the deviation
survey there is an additional azimuth entry.
7.8.2.4
Completion Data
The completion data screen represents tubing and a completion. Hence, it is a superset of
the tubing data screen and is the same except for one extra tabbed dialog in the data input
screen, for completion data. This dialog has fields in it similar to the single well IPR WongClifford model for describing a deviated completion (completion zone start and end
measured and true depths) as well as a field for entering a local (mechanical/geometric)
skin value. There is a drop-down list box in the fifth column, which allows the skin to be
calculated using the Karakas & Tariq method. The selection of ‘Karakas and Tariq’
enables the push button in the last column, which brings up an appropriate data entry
screen when clicked upon with the mouse left button. On entering valid data and exiting
that screen with Done the skin value is calculated and entered in the skin data column.
7.8.2.5
Reservoir Data
Model Selection Screen
The model selection screen contains a model selection list box for selecting a Darcy-like
reservoir model as well as several data entry fields for entering PVT and geometrical data
used by all the models.
Data Input Screen
The data input screens contain a single sub-dialog pertaining to the model chosen. These
are similar to the equivalent models in the single well case.
Consistency Validation
Beyond the consistency enforced by the validation of individual network items as they are
edited and the automatic entry of some child branch data from parents, there are other
checks carried out on a complete structure whose nodes are individually valid:
•
•
•
•
There must be no more than one tie-point in a network; other loose items are ignored.
The top node must be a tie-point.
All branches must end in a completion, completions must be attached to at least one
reservoir.
Reservoirs should not overlap in depth (in the current model they are assumed to be
layers).
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7.8.3
7.8.3.1
Example of How to Set Up a Simple System
Introduction
The purpose of this exercise is to enter some geometrical data for the simple multilateral in
the following ‘back of an envelope’ sketch (see Figure 7.56 below) and then visualise it
using the Visualise menu. It is assumed that the fluid selected is ‘Oil and Water’ and the
units system is oilfield units. We will also show the procedure for running a calculation, to
which purpose some default PVT and geometric data should be entered in the reservoir
screens. The multilateral has two branches, with one branch having an azimuth of 170°
with respect to the other. The zig-zag lines indicate completions and the areas between
the horizontal straight lines are layers/reservoirs. Note that one tubing branch contains two
completions and goes through two reservoirs. This will be modelled as one completion
node and logically attached to two reservoirs. The point at (12000, 10000) feet will serve
as a tie-point.
(0, 0) = (measured depth, vertical depth)
(12000, 10000)
(12100, 10020)
10000 feet
(12200, 10020)
Kh = 100 mD
(12400, 10100)
10100 feet
Azimuth = 170 deg.
Azimuth = 0 deg.
10200 feet
Kh = 50 mD
(13000, 10210)
(13000, 10220)
(14000, 10220)
10300 feet
(14000, 10280)
Figure 7-56 Sketch of a Multi-lateral Network
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Place the Nodes in the Network Window
The nodes needed are one tie-point (as always), a junction (to model the branching), two
completions (although there are three zones, the data for two will be contained in one
node), and two reservoirs. Each node can be selected from one of the following:
1. Using the Tools | Add Item option in the frame window menu.
2. Clicking on the appropriate icon in the toolbar.
3. Selecting the required option from the drop-down list box in the toolbar.
4. Using the right hand mouse button menu.
Once the appropriate node addition option has been selected, click somewhere in the
blank network window to create an icon. Allow the programme to attach a default label to
the node by not entering one. Do this for all the required nodes listed above.
7.8.3.3
Connect the Nodes
Before doing the connections, space the nodes and arrange them in height order with the
tie-point at the top, followed by the junction, followed by the completions and put the
reservoirs at the bottom. Keep the completions and reservoirs at the same horizontal level
with C1 and R1 on the left. Now select the link option and drag the mouse cursor (with the
left button down) between the following icons in order to make the connections: TP1-J1,
J1-C1, J1-C2, C1-R1, C2-R1 and C2-R2. Note that between the tie-point and the junction
a tubing icon is drawn to indicate that this link contains tubing data. The order of the
connections J1-C1 and J2-C2 are important for the reverse would imply that the
completions were above the junction hierarchically.
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7.8.3.4
Enter the Data
To enter data, double-click on an icon to bring up a screen.
Tie-point (TP1)
Enter 12000 feet and 10000 feet for measured and vertical depth respectively and then
click on Done.
Tubing (T1)
Make sure that ‘Flow Type’ is ‘Tubing Flow’ on the model selection screen and a suitable
value (0.354 ft) is entered for well-bore radius. Then leave the model selection screen with
its other defaults and enter the data input screen using the button Input Data in the top
right hand corner. In the ‘Deviation’ tabbed dialog enter the three numbers:
12100
10020
0
in the white boxes in row 2. Now enter the ‘Equipment’ tabbed dialog by clicking on that
tab. In row 1 choose ‘Tubing’ from the drop-down list box and then enter the four numbers:
12100
0.7
0.0006 1
in the white boxes in row 1. Click on Done to finish.
Junction (J1)
The co-ordinates (12100, 10020) should already be entered in the junction net item.
Completions (C1 and C2)
The model selection screens should be as with T1 except a Dietz shape factor should be
entered (e.g. 31.6). The other screens should have their white spaces filled as follows. In
the equipment screens the first row drop-down list box should always be set to ‘Tubing’.
C1 Deviation
13000
10210
14000
10280
C1 Equipment
14000
0.7
C1 Completion Info.
13000
14000
170
170
(row 2)
(row 3)
0.0006 1
(row 1)
10210
10280
1
(row 1)
10100
10220
1
1
(row 1)
(row 2)
C2 Deviation
12400
10100
0
13000
10220
0
14000
10220
0
C2 Equipment
14000
0.7
0.0006 1
C2 Completion Info.
12200
12400
10020
13000
14000
10220
(row 2)
(row 3)
(row 4)
(row 1)
Reservoirs (R1 and R2)
For both reservoirs select ‘Darcy’ as the model. The edit fields for entry of the data for this
model should appear on clicking on Input Data. In order to agree with the specifications of
the sketch enter the following data:
R1
Reservoir Top Depth: 10200 feet
Reservoir Permeability:
50 md
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Reservoir Thickness: 100 feet
R2
Reservoir Top Depth: 10000 feet
Reservoir Permeability:
100 md
Reservoir Thickness: 100 feet
The other fields in the model selection and data input screens (for both reservoirs) should
be entered with some reasonable numbers. For example: pressure (5000), temperature
(200), salinity (150000), water cut (15), GOR (800), gas gravity (0.9), oil gravity (30),
vertical permeability (10) and drainage area (500).
7.8.3.5
Visualise / Calculate
Choosing Visualise |Front should show a picture similar to the one in the sketch in Figure
7-53. Also, providing the data has been entered correctly, the network structure should be
valid; this can be verified by going to the screen brought up by the Analyse| Calculate
menu command and choosing one of the calculations. Note that this exercise is not meant
to represent a real case but only a reasonable set of data that the programme can process.
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PROSPER MANUAL
8 Artificial Lift Data Input
This section describes how to enter the description of artificial lift equipment in a well for
calculating a systems analysis. The Design section (Chapter 11) describes how to select
suitable gas lift, ESP equipment or HSP equipment for new or existing wells.
8.1 Gas Lift Input Data
This option is available only when Gas Lift has been selected as the lift method in the
Options menu. To analyse an existing gas lifted well, the equipment details must be
entered in this section. To design a new gas lift installation, skip the System  Gas lift data
menu and go directly to Design  Gaslift Design (New Well) (Section 11.1). Note that the
Gaslift design section has been revised to give users greater flexibility in choice of design
methods.
The required input depends on your choice of casing pressure calculation method. In
order of increasing complexity:
•
Gas lifted (no friction dP)
No flowing pressure losses occur in the annulus. A static gas gradient in the
casing is assumed. This model should be used for the majority of gas lift
installations.
•
Gas lifted (friction dP)
The friction pressure drop in the casing is calculated. Input of both tubing
O.D. and casing I.D. is required to define the annulus geometry.
•
Gas lifted (safety equipment)
Friction pressure losses are calculated in the surface piping, tubing/casing
annulus and an annular safety valve where fitted.
To analyse an existing installation, the gas lift details that need to be entered will depend
upon the particular gas lift method that has been selected.
Firstly select the gas lift system type on the Options menu, then enter the well data by
selecting Gaslift data on the System menu. Enter the required lift gas composition data and
select one of three gas lift methods available. The methods currently available are:
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8.1.1
CHAPTER 8 - ARTIFICIAL LIFT DATA INPUT
Fixed Depth Of Injection
When this method is selected, only the depth of injection will be asked for.
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The program assumes that the casing pressure is sufficient to inject lift gas at the
specified depth to achieve the GLR injection target.
The GLR injected can be subsequently overwritten when calculating Sensitivities. If the
GLR injected is unknown, leave it set to zero. The GLR to inject is set using Sensitivity
variables GLR injected or Injection gas rate in the Calculation section.
Figure 8-1
Gas Lift Data Input
Fixed Depth of Injection
8.1.2 Optimum Depth of Injection
When this method is selected enter the maximum depth of injection, the dP across the gas
lift valve and the top casing pressure.
Figure 8-2
Gas Lift Data Input
Optimum Depth of
Injection
For the Gas lifted (safety equipment) option, the compressor discharge pressure is
requested instead of the casing pressure.
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Use Optimum Depth of Injection to evaluate the potential increase in
production due to gas lift without the need to perform a detailed design and
spacing the unloading valves.
8.1.3 Valve Depth Specified
Enter the measured depth of the gas lift valves. The program automatically calculates
which valve opens for particular liquid and gas injection rates.
Figure 8-3
Gas Lift Data Input
Valve Depth Specified
If a gas lift design has already been done, or the mandrel depths have been entered for a
Gaslift QuickLook the valve details can be copied across using the Transfer button.
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The Casing pressure entered should be the available injection system pressure
for the current operating conditions If calculating sensitivities for a new casing
pressure operated design, always subtract the dP to close valves for each
unloading valve above the operating valve from the design casing pressure.
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CHAPTER 8 - ARTIFICIAL LIFT DATA INPUT
8.1.4 Gas Lift (Safety Equipment)
For the Gas Lifted (safety equipment) option, the annular safety valve pressure losses are
calculated using the valve depth and ‘bean diameter’ entered on the System  Gaslift Data
screen as follows:
Figure 8-4
Gas Lift (Safety
Equipment) Input
The details of the surface injection system are used to calculate the casing head pressure
as a function of gas injection rate and compressor output pressure. Frictional losses in the
annulus are taken into account when calculating the casing pressure at each gas lift valve
depth. The safety valve pressure loss is clearly seen on the following gradient plot:
Figure 8-5
Gas Lift (Safety
Equipment)
Pressure Traverse
8.1.5 Gas Lift (Allow injection in Pipe Line above wellhead)
A new option implemented in this version is the ability to consider gas injection in the
pipeline. Using this option, the program will not allow you to perform conventional gas lift
design.
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Figure 8-6
Gas Lift (pipe line) Input
Figure 8-7
Gas Lift (pipe line) Input
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CHAPTER 8 - ARTIFICIAL LIFT DATA INPUT
8.2 ESP Input Data
If Electrical Submersible Pump has been selected as the well lift method on the Options
screen, then Electric Submersible Pumps.. will be highlighted on the System input menu. If
you are designing a new ESP installation, the equipment has not yet been sized, so skip
the ESP Input section entirely. For analysis and optimisation of an existing ESP
installation, enter the data on the ESP input data screen as requested:
Figure 8-8
ESP Input Data
The Pump wear factor is used to account for deviation from the manufacturer's published
performance curves due to wear etc.
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For example, entering 0.05 causes the program to scale the pump head curves
down by 5% (i.e. head is 95% of the database value).
Entering 0 causes the program to use the database curves directly.
A negative number can be entered to simulate a particular pump that performs
better than the database curve.
When a downhole gas separator is run, the GOR of the oil above the separator will be
lower than the produced oil GOR. Depending on the completion, the separated gas is
produced up the annulus or a separate tubing string. Both casing I.D. and tubing O.D. are
required to be input on the System  Equipment  Downhole Equipment.
Use the Pump, Motor and Cable buttons to select from a database of equipment
characteristics. Use the list box at the right hand side of the screen or the << and >>
buttons to scroll through the database to locate the required unit. Then, click OK to return
to the ESP input data screen. A typical database screen for pumps is shown below:
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Figure 8-9
ESP Pumps
Database
Motors are grouped by series. Select the series, then choose the required horsepower and
voltage option. An example ESP motor database screen is shown below:
Figure 8-10
ESP Motors
Database
Different types of cable may also be chosen to model varying requirements at surface. An
example ESP cable database screen is shown below:
Figure 8-11
ESP Cables
Database
The ESP equipment database is maintained through the Design  ESP Database menu as
described in the ESP design section. A summary report of the ESP equipment input data
can be viewed or printed by clicking the Report button. Further details of database
maintenance methods are given in ESP Design (Section 11.4).
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Â
CHAPTER 8 - ARTIFICIAL LIFT DATA INPUT
Every effort is made to ensure that the sample pump and motor coefficients
supplied with PROSPER are current. However, it is the User’s responsibility to
ensure they are both accurate and up-to-date. For critical design work, always
refer to your equipment supplier for the latest performance data.
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8.3 HSP Input Data
If Hydraulic Drive Downhole Pump has been selected as the well lift method on the Options
screen, then Hydraulic Submersible Pumps.. will be highlighted on the System input menu.
If you are designing a new HSP installation, the equipment has not yet been sized, so skip
the HSP Input section entirely. For analysis and optimisation of an existing HSP
installation, enter the data on the HSP input data screen as requested:
Figure 8-12
HSP Input Data
The Pump wear factor is used to account for deviation from the manufacturer's published
performance curves due to wear etc.
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For example, entering 0.05 causes the program to scale the pump head curves
down by 5% (i.e. head is 95% of the database value).
Entering 0 causes the program to use the database curves directly.
A negative number can be entered to simulate a particular pump that performs
better than the database curve.
Turbine speed is assumed to be the same as the Pump speed. The % Power Fluid of
Reservoir Fluid defines what fraction of the total produced liquids the power fluid
represents.
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A figure of 100% means that the amount of power fluid used to drive the turbine
is the same as the amount of produced reservoir fluids.
Use the Pump, and Turbine buttons to select from a database of equipment characteristics.
Use the list box at the right hand side of the screen or the << and >> buttons to scroll
through the database to locate the required unit. Then, click OK to return to the HSP input
data screen. A typical database screen for pumps is shown below:
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Figure 8-13
HSP Pumps
Database
An example HSP motor database screen is shown below:
Figure 8-14
HSP Turbines
Database
The HSP equipment database is maintained through the Design  HSP Database menu as
described in the HSP design section. A summary report of the HSP equipment input data
can be viewed or printed by clicking the Report button. Further details of database
maintenance methods are given in HSP Design (Section 11.5).
Â
Every effort is made to ensure that the sample pump and turbine coefficients
supplied with PROSPER are current. However, it is the User’s responsibility to
ensure they are both accurate and up-to-date. For critical design work, always
refer to your equipment supplier for the latest performance data.
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8.4 Progressive Cavity Pumps
If PCP option has been selected as the well lift method on the Options screen,
then the progressive cavity Pump option will be highlighted on the System input
menu.
This section describes the Progressing Cavity Pump design in PROSPER. The main
purpose is to provide a brief background of the use of the pump, how to set the pump data
base and nodal analysis design considering the PCP.
The Progressing Cavity Pump (PCP) is also known as screw pump or Moineau pump. This
type of lifting system still not yet widely used and it is mostly applied on heavy oils and
shallow wells.
Principle
The PCP consist of
-Helical rotor
-Stator
the geometry of the assembly is such that it constitutes a series of identical separate
cavities, when the rotor is rotated inside the stator these cavities move axially from one
end of the stator to the other, from suction to discharge creating the pumping action.
Because the cavities are sealed from each other, the pump is of the positive displacement
type.
In general terms the geometry of the pump is defined by the following parameters:
Diameter of the rotor
Eccentricity
Pitch length of the stator
D
E
P
The minimum length required by the pump to create an effective pumping action is the
pitch length ; which is then one stage, each additional pitch length will provide an
additional pump stage.
Figure 8.15
Rotor and
Stator
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As the pump rotates the rotor produces two cavities of fluid, the figure below shows a
typical configuration of the pump. The rotor, usually made out of chrome plated steel, it
hangs from the drive head by string of standard sucker rods. The surface equipment
includes the drive head which carry all the axial load of the roads, transmit the rotational
movement to the entire rod string and seal the drive system from the well fluid.
Usually the drive system is an electric motor and the transmission may be fixed or variable.
When the user select Progressive cavity pump, there are two options to consider.
• Sucker rod pump drive
• Downhole motor drive
The stator is made out of elastomer encased into the steel pipe and this is attached to the
tubing string.
In order to create a lifting pressure there must be a differential pressure between the
cavities, therefore a thigh seal between rotator and stator is required; however there will be
always slippage of the production fluid due to:
•
•
•
•
Differential pressure
Number of stages
Fluid properties
Temperature and type of material
8.4.1 PCP Input Data
For analysis and optimisation of an existing PCP installation, enter the data on the PCP
input data screen as requested:
Figure 8.16
PCP Input Data
In order to select the correspondent pump and rods, the pump data base must be set up
first. Chapter 11 describe how to enter the correspondent pump and rods data base.
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8.5 Gas Lift with coil tubing
This option is available only when Gas Lift with coil tubing is selected as the lift method in
the Options menu. To analyse an existing installation or perform a gradient calculation
considering certain depth of injection select specified injection depth. To design a new gas
lift installation with coil tubing consider the optimum depth of injection option.
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Considering fixed depth of injection, the program assumes that the casing
pressure is sufficient to inject lift gas at the specified depth to achieve the GLR
injection target.
Figure 8.17
Coiled Tubing
Data
When the optimum injection depth is selected the maximum depth of injection, casing
pressure and pressure drop across the valve is required. Performing a design the program
will determine the optimum conditions for the installation. Chapter 11 provides more
information about the design.
SEPTEMBER 2003
PROSPER MANUAL
9 Matching Menu
PROSPER matching is used for data quality control and fine adjustment of model
parameters to enable well models to reproduce observed data. A properly matched model
is a pre-requisite for accurate performance prediction.
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The Quality Control exercises like Correlation comparison are based on what is
possible according to the principles of fundamental physics.
The Matching menu offers the following calculation options:
QuickLook (Artificial lift wells only)
Allows calculation of the pressure gradient in an artificially lifted well for a quick check of lift
performance.
For gas lifted wells, valve opening and closing pressures are calculated to permit
troubleshooting gas lift installations.
For ESP and HSP wells, the performance of the ESP and HSP can be checked.
Correlation Comparison
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This is the primary step in quality control of measured well test data.
This option allows pressure gradient plots to be generated with different correlations to be
compared with measured gradient survey data and each other for both tubing and pipeline
correlations. On basis of this comparison the user can determine if the measurements
“make sense” based on the principles of physics (See Section 9.2)
VLP / IPR Matching
This option enables you to tune the well bore multiphase flow correlations to fit a range of
measured down hole pressures and rates. Up to 10 pressure tests can be matched
simultaneously. Once the VLP is matched, the IPR can be adjusted to match observed
rates and pressures also.
Gradient Matching
Existing correlations can be modified using non-linear regression to best fit a gradient
survey. Comparison of the fit parameters will identify which correlation required the least
adjustment to match the measured data.
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This should be used only if for a given rate more than one measurement is
available along the production string.
2 - 28
CHAPTER 9 - MATCHING MENU
Surface Pipe Matching
The program uses actual wellhead and manifold pressures together with temperature data
points to match surface pressure drop correlations. Separate screens allow the match
parameters to be viewed and the best match selected.
Tubing Correlation Parameters
The VLP match parameters can be inspected, reset or entered by hand using this menu
option. This capability is useful for troubleshooting, or to input match parameters
determined previously.
Pipeline Correlation Parameters
The flow line match parameters can be inspected, reset or entered by hand using this
menu option.
Correlation Thresholds
This option allows the user to specify a threshold angle for both tubing and pipeline
correlations at which the program will automatically change to another (specified)
correlation. This option will enable vertical risers in sub sea completions to be modelled
more accurately
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9.1
VLP Matching is not available for Enthalpy Balance temperature model
applications. For Enthalpy Balance applications requiring VLP matching, use the
Predicting Pressure Only, or the Rough/Improved Approximation temperature
model, to perform the correlation matching. Once the matching operation has
been completed, return to System and re-activate the Enthalpy Balance option.
The VLP match parameters will be carried over.
A Note on VLP Correlation Applications
Fancher Brown is a no-slip hold-up correlation that is provided for use as a quality control.
It gives the lowest possible value of VLP since it neglects gas/liquid slip it should always
predict a pressure, which is less than the measured value. Even if it gives a good match to
the measured down hole pressures, Fancher Brown should not be used for quantitative
work. Measured data falling to the left of Fancher Brown on the correlation comparison
plot indicates a problem with fluid density (i.e. PVT) or field pressure data. This is thus
essentially, a correlation for quality control purposes.
For oil wells, Hagedorn Brown performs well for slug flow at moderate to high production
rates but well loading is poorly predicted. Hagedorn Brown should not be used for
condensates and whenever mist flow is the main flow regime. Hagedorn Brown under
predicts VLP at low rates and should not be used for predicting minimum stable rates.
Duns and Ros Modified usually performs well in mist flow cases and should be used in
high GOR oil and condensate wells. It tends to over-predict VLP in oil wells. Despite this,
the minimum stable rate indicated by the minimum of the VLP curve is often a good
estimate.
Duns and Ros Original is the original published method, without the enhancements
applied in the primary Duns and Ros correlation. The primary Duns and Ros correlation in
PROSPER has been enhanced and optimised for use with condensates.
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Petroleum Experts correlation combines the best features of existing correlations. It uses the
Gould et al flow map and the Hagedorn Brown correlation in slug flow, and Duns and Ros
for mist flow. In the transition regime, a combination of slug and mist results is used.
Petroleum Experts 2 includes the features of the PE correlation plus original work on predicting
low-rate VLPs and well stability.
Petroleum Experts 3 includes the features of the PE2 correlation plus original work for viscous,
volatile and foamy oils.
Petroleum Experts 4 is an advanced mechanistic model for any angled wells (including downhill
flow) suitable for any fluid (including Retrograde Condensate).
Orkiszewski correlation often gives a good match to measured data. However, its
formulation includes a discontinuity in its calculation method. The discontinuity can cause
instability during the pressure matching process; therefore we do not encourage its use.
Beggs and Brill is primarily a pipeline correlation. It generally over-predicts pressure
drops in vertical and deviated wells.
Gray correlation gives good results in gas wells for condensate ratios up to around 50
bbl/MMscf and high produced water ratios. Gray contains its own internal PVT model
which over-rides PROSPER’s normal PVT calculations.
Hydro 3P (internal) is a mechanistic model and considers three phase flow.
Â
For very high liquid dropout wells, use a Retrograde Condensate PVT and the
Duns and Ros correlation.
Â
There is no universal rule for selecting the best flow correlation for a given
application. It is recommended that the Correlation Comparison always be
carried out. By inspecting the predicted flow regimes and pressure results, the
user can select the correlation that best models the physical situation.
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CHAPTER 9 - MATCHING MENU
9.2
Correlation Comparison
This module allows a pressure gradient (traverse) to be calculated at a specified surface
rate using any of the standard correlations. Actual measured pressures can be input and
plotted on the same graph for comparison with the pressure calculated from the
correlations. The correlations may be modified or unmodified.
Click Matching  Correlation comparison to display the following data entry screen:
Figure 9-1
Correlation Comparison
Input
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Note that in Correlation comparison, the first node is the wellhead only if there is
no surface equipment or it has been disabled.
Enter the surface flowing conditions at which you want to compare the correlated gradients.
Select a surface equipment correlation then click on the required downhole correlations to
select a number of them from the list.
Â
Ensure that the rate type is correct for your application.
The value of GOR should reflect the current solution GOR and at no time should
exceed the initial solution GOR.
The GOR Free variable is used to model the effect of free gas production from a
gas cap or injection gas breakthrough. Leave GOR Free set to zero if there is no
free gas production.
The sum of GOR and GOR Free should equal the producing GOR.
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Pressure data from a gradient survey can be entered versus depth in the measured data
boxes. The Transfer button copies the measured depths and pressures to the Gradient
match section.
Â
For gas lifted wells, both the injection depth and gas lift injection rate are required
to be input.
Note that the producing GOR should not include the lift gas injection.
When the input data is complete, click on Calculate to display the calculations screen, then
press the Calculate button to compute the pressure gradient in tabular form as shown
below:
Figure 9-2
Correlation
Comparison
Calculations
The results of individual correlations can be examined sequentially by clicking the arrows
beside the Correlation field.
For all the correlation selected for calculations, use the scroll thumb below the results box
to access the results of calculations.
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CHAPTER 9 - MATCHING MENU
PROSPER displays the following parameters as a function of depth:
• Temperature, Pressure.
• Total Pressure Gradient, Static gradient, Friction Gradient.
• Flow regime, Liquid Hold up, Water Hold up, cumulative hold ups.
• Slip Liquid Velocity, Superficial Liquid Velocity, Slip Gas Velocity, Superficial Gas
Velocity, Slip Water Velocity, Superficial Water Velocity.
• Mixture Density, Gas density, Oil density, Water density.
• Frictional Pressure Loss, Gravity Pressure Loss
• Pipe Diameter, Angle of the tubing From Vertical, calculation Node Length
• Liquid Viscosity, Gas Viscosity, water viscosity, oil viscosity, Gas-Liquid IFT, GasWater IFT, Gas-Oil IFT, Oil-Water IFT
• C Factor and the max size of sand grain that can be transported
• Cumulative volumes of phases till that depth.
A visual comparison of all selected correlations and the test data is easily made by clicking
on the Plot button. The plot can be output or saved using the standard features of
PROSPER and Windows. An example comparison plot is shown below:
Figure 9-3
Correlation
Comparison
Plot
This plot is a useful quality check on the PVT and field production data. The Fancher
Brown correlation does not allow for gas/liquid slippage, therefore it should always predict
a pressure that is less than the measured value. Measured data falling to the left of
Fancher Brown on the gradient comparison plot indicates a problem with fluid density (i.e.
PVT) or the field data (pressure or rate). The use of the gradient comparison plot is
recommended to help identify flow regimes and assess input data quality.
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QuickLook for Gas Lift
The QuickLook option is based on the principle of calculating well pressure traverses in
opposite directions beginning from known conditions at the surface and sand face. If the
assumptions regarding well conditions (e.g. gas injection rates and depth, water cuts, IPR
etc.) are correct, the two calculated traverses would overlay.
Troubleshooting a gas lifted well is performed by considering a range of assumptions, until
a consistent calculation model can be obtained. By varying artificial lift and production
parameters in turn, the experienced user can determine if the well is behaving as designed,
or identify potential reasons to explain the deviation from design conditions.
9.3.1 Input
The gas lift QuickLook is accessed from the Matching menu. Clicking QuickLook from the
Matching menu displays the following screen:
Figure 9-4
Gas lift QuickLook Input
The surface measurements section contains two columns for data input.
Â
For analysing a particular well at a particular flowing condition, enter data in the
Minimum column only.
For unstable wells, enter the minimum and maximum conditions to be
considered. The program will calculate using average values.
If unloading valve details have been entered, their opening and closing pressures will be
shown on the plot also.
The parameters required to be entered are:
Tubing head pressure
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Enter expected flowing pressure for the well.
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CHAPTER 9 - MATCHING MENU
Tubing head temperature
Liquid rate
Water cut
Total gas rate
Gas injection rate
Casing head pressure
Orifice diameter
Injection depth
Vertical flow correlation
Dome Pressure Correction
above 1200 psi
Used only for comparison purposes.
Enter current flow rate.
Enter current value.
Enter total gas production through the separator - including the lift gas
contained in the produced well stream.
Enter current injection rate.
Enter current surface gas injection pressure.
Enter diameter of orifice where gas is entering the string. This diameter is
used to estimate the pressure drop between casing and tubing at the
injection depth. For wells having multiple injecting orifices at the same
depth, enter an equivalent area.
Enter expected depth of injection.
Select the most appropriate correlation for your application. Use a matched
correlation where available.
When set to Yes, the improved high-pressure dome pressure temperature
method is used.
To compare measured and calculated pressures to those calculated by the QuickLook,
click Downhole, and enter your pressure survey data in the following screen:
Figure 9-5
QuickLook Downhole
Measurements
The purpose of this section is to check that all the data is consistent. The static gradient
can also be displayed on the plot by entering two static pressure measurement points.
Downhole measurement entry is optional.
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If a static pressure is entered on the downhole measurement screen, this will be
used to calculate the sand face pressure from the IPR.
For PROSPER to determine which gas lift valves should be open and closed for the current
producing conditions, the valve depths and characteristics must first be entered. Click
Valves from the QuickLook screen to display the following:
Figure 9-6
QuickLook
Valve Data
The valve type (casing or tubing sensitive), setting depth, port size, R-value and dome
pressure at 60 °F are required to calculate whether valves are open or closed. Opening
pressure etc. fields will be blank until a QuickLook calculation has been performed.
Entering the valve data for the QuickLook is optional.
As an alternative to entering them by hand, gas lift valve characteristics can be transferred
from other sections of PROSPER. Click the Transfer button on the Valves data entry
screen, and you will be prompted to select the source of valve data. Select either From
Gas lift valves, or From Gas lift design to pick up the depths that have been previously
entered in Equipment  Gaslift. After Transferring the valve depths, select the valve type
for each depth. To manually investigate the effects of changing R-values and dome
pressures, these values may be edited or entered by hand.
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9.3.2 Performing the QuickLook Calculation
Once the required (diagnostic) and optional (Downhole & Valves) data have been entered,
click Calculate to display the calculation screen and Calculate again to begin the
computation of the gradients. PROSPER begins by calculating from the top down, and then
repeats the calculation from the sand face up.
Select between the up pass and down pass using the buttons located beside the Case box
as in the following example:
Figure 9-7
QuickLook Diagnostic
Calculations
In the Results box, the program displays the theoretical dP across the injecting valve
together with the casing pressure theoretically required to balance the flowing tubing
pressure at the injection depth plus the dP across the orifice.
Click Plot to display the two computed gradients plus the valve opening and closing
pressures on the same graph:
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Figure 9-8
QuickLook
Diagnostic
Plot
This plot enables the user to see at a glance which valves should be open or closed, and
how changes in operating pressures would impact on the valves. The results box displays
the following computed values:
Flowing BHP
From the IPR at the current flow rate.
Static BHP
Reservoir pressure input.
Tubing pressure at valve
Fluid side pressure at injection depth.
Casing pressure at valve
Gas side pressure at injection depth.
Temperature at valve
Interpolated for Predicting pressure only option. Can also be
calculated using the Rough Approximation temperature option.
GOR
Calculated from production and injection rates and PVT.
GOR Free
Calculated from production and injection rates and PVT.
dP across valve
Pressure loss resulting from injection through the valve orifice.
Theoretical casing pressure
Pressure at surface back calculated from the tubing pressure at
injection depth plus the dP across the operating valve less the gas
pressure traverse back to surface.
Producing draw down
Difference in static and flowing sand face pressures.
Equivalent P.I.
When flowing above bubble point, the production rate divided by
the producing draw down.
Critical flow rate
Injection rate required for sonic velocity through the orifice.
% Critical flow rate
Actual injection rate as a fraction of the critical rate.
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9.4
QuickLook for ESP
The ESP QuickLook principle is identical to that for gas lift wells, i.e. pressure traverses are
calculated from top to bottom and vice-versa. If the assumptions regarding well and ESP
conditions (e.g. pump frequency, wear factor, water cuts, wellhead pressure, IPR etc.) are
correct, the two calculated traverses will overlay. In addition, an energy balance is
performed across the electrical system allowing surface voltage and power to be calculated
and compared to measured data.
Historically, ESP wells have been difficult to diagnose (particularly with limited down hole
pressure data) because of uncertainties below (IPR), across (pump head) and above
(tubing hydraulics) the pump. Using the ESP QuickLook, conditions in each of these areas
can be analysed separately.
9.4.1 Input
The ESP QuickLook is accessed from the Matching menu. Clicking QuickLook from the
Matching menu displays the following screen:
Figure 9-9
ESP Quicklook
Input
Select the required pump, motor and cable from the buttons at the top of the screen.
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Enter well test parameters as follows:
Tubing head pressure
Liquid rate
Water Cut
Produced GOR (solution GOR plus free gas)
Static Bottom Hole Pressure (reservoir
pressure)
Enter measured data as follows:
Surface current, voltage and
power
Downhole pressure data
(Self-explanatory)
Enter gauge data if available, usually pump intake and pump
discharge pressures
Enter ESP related parameters as follows:
Pump depth
Operating frequency
Length of cable
Gas separation
efficiency
Number of stages
Pump wear factor
Enter correlation
(Self-explanatory)
(Self-explanatory)
Used to calculate surface voltage. Normally the same as the pump depth,
but could be much longer for sub sea ESP wells.
Enter the percentage of free gas at the pump intake that is separated and
flows up the annulus.
(Self-explanatory)
Enter the fraction that represents degradation of pump head. Zero is no
wear, one indicates no head will be developed. This can be used to model
pumps stages that are worn due to sand or scale production or any other
factor that downgrades pump performance.
Select the most appropriate flow correlation for your application. Use a
matched correlation where available
9.4.2 Performing the QuickLook Calculation
Click Calculate to display the calculation screen and Calculate again to begin the
computation of the pressure traverses.
Â
Note that PROSPER always calculates from the bottom up for ESP systems since,
in order to find the tubing GOR above the pump, conditions at the pump intake
where gas separation takes place must be known. The calculation of the
downward pressure traverse from the entered tubing head pressure is therefore
iterative.
Select between the up pass and down pass using the buttons located beside the Case box
as in the following example:
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Figure 9-10
Calculation
Output Screen
Click Plot to display the pressure traverses and the calculated pump intake and discharge
pressures, down hole average rate across the pump (RB/day), free gas fraction at the
pump intake and electrical parameters:
Figure 9-11
ESP Output
Plot
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If the well bore, inflow and ESP assumptions are all correct, the two pressure traverses will
overlay and the measured and calculated intake and discharge pressures and surface
voltages should coincide.
The following guidelines may be useful in diagnosing ESP wells:
Â
The pump discharge pressure is the “tie” point for the system. First match the
pump discharge pressure (if available) from the top down traverse. The pump
discharge pressure depends only on the weight and frictional resistance to the
flow rate through the tubing to surface.
Next match the pump intake pressure from the top down traverse. If the
calculated and measured pressure differential (head) across the pump is
different, then the assumptions of pump wear, fluid density (water cut) and pump
frequency should be examined.
The top down traverse will now give the resulting bottom hole flowing pressure.
This should be compared with the bottom up calculation and will indicate any
discrepancy with the inflow performance module assumptions.
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9.5
QuickLook for HSP
The HSP QuickLook principle is identical to that for ESP wells, i.e. pressure traverses are
calculated from top to bottom and vice-versa. If the assumptions regarding well and HSP
conditions (e.g. pump and turbine speed, wear factor, water cuts, wellhead pressure, IPR
etc.) are correct, the two calculated traverses will overlay.
9.5.1 Input
The HSP QuickLook is accessed from the Matching menu. Clicking QuickLook from the
Matching menu displays the following screen:
Figure 9-12
HSP Quicklook
Input
Select the required pump and turbine from the buttons at the top of the screen.
Enter well test parameters as follows:
Tubing head pressure
Liquid rate
Water Cut
Produced GOR (solution GOR plus free gas)
Static Bottom Hole Pressure (reservoir pressure)
Enter measured data as follows:
Downhole pressure data
Enter gauge data if available, usually pump intake and pump
discharge pressures
Enter HSP related parameters as follows:
Pump depth
Pump Speed
% of Total Production For Power
Fluid
Number of Pump stages
PETROLEUM EXPERTS LTD
(Self-explanatory)
(Self-explanatory)
This defines what fraction of the total produced liquids the
power fluid represents.
(Self-explanatory)
CHAPTER 9
Pump wear factor
Number of Turbine Stages
Enter correlation
17 - 28
Enter the fraction that represents degradation of pump head.
Zero is no wear, one indicates no head will be developed.
(Self-explanatory)
Select the most appropriate flow correlation for your
application. Use a matched correlation where available
9.5.2 Performing the QuickLook Calculation
Click Calculate to display the calculation screen and Calculate again to begin the
computation of the pressure traverses. Note that PROSPER always calculates from the
bottom up for HSP systems since, in order to find the tubing GOR above the pump,
conditions at the pump intake where fluid mixing takes place must be known. The
calculation of the downward pressure traverse from the entered tubing head pressure is
therefore iterative.
Select between the up pass and down pass using the buttons located beside the Case box
as in the following example:
Figure 9-13
Calculation
Output Screen
Click Plot to display the pressure traverses and the calculated pump intake and discharge
pressures, down hole average rate across the pump (RB/day) and pump and turbine
parameters:
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Figure 9-14
HSP Output
Plot
If the well bore, inflow and pump and turbine assumptions are all correct, the two pressure
traverses will overlay and the measured and calculated intake and discharge pressures
and surface voltages should coincide.
The following guidelines may be useful in diagnosing HSP wells:
Â
The pump discharge pressure is the “tie” point for the system. First match the
pump discharge pressure (if available) from the top down traverse. The pump
discharge pressure depends only on the weight and frictional resistance to the
flow rate through the tubing to surface.
Next match the pump intake pressure from the top down traverse. If the
calculated and measured pressure differential (head) across the pump is
different, then the assumptions of pump wear, fluid density (water cut) and pump
speed should be examined.
The top down traverse will now give the resulting bottom hole flowing pressure.
This should be compared with the bottom up calculation and will indicate any
discrepancy with the inflow performance module assumptions.
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VLP/IPR Match and Quality Check
This feature enables you to adjust the multiphase flow correlations to match flowing bottom
hole pressure surveys or production logging runs. Up to 10 pressure tests can be matched
simultaneously. VLP/IPR Match allows data to be matched over a range of rates as well as
depths. Gradient Matching (Section 9.7) is carried out over a range of depths at one
specific flow rate.
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The formation GOR is the solution GOR. If there is no free gas production at the
sand face, GOR free should be set to zero.
Figure 9-15
VLP/IPR
Match Input
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The user can now use the ‘Correlation Comparison’ button to transfer the
selected well test data to the correlation comparison section. The procedure is:
•
•
•
Â
Click on the button to the left of the well test data that we wish to perform
correlation comparison on.
Click on the ‘Correlation Comparison’ button
PROSPER will bring us to the correlation comparison screen and at the
same time, populate the correlation comparison screen with the selected
well test data.
If the temperature prediction method is ‘Rough Approximation’, the user can now
use the ‘Estimate U value’ button to estimate the overall heat transfer coefficient
for the selected well test. The procedure is:
•
•
•
•
SEPTEMBER 2003
Click on the button to the left of the well test data that we wish to estimate
the overall heat transfer coefficient.
Click on the ‘Estimate U value’ button
PROSPER will estimate the overall heat transfer coefficient that matches
the wellhead temperature of the well test.
The user can then go to the Geothermal Gradient section to change the
overall heat transfer coefficient value.
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9.6.1 VLP Matching
The required input data are:
Tubing Head Pressure
Tubing Head Temperature
Water Cut
Rate
Gauge Depth
Gauge Pressure
GOR
GOR Free
Gaslift Gas Rate
Injection Depth
Flowing pressure for test rate entered.
Flowing temperature at test rate. Usually has only a minor effect.
Test water cut.
Enter either Oil or Liquid rates as selected.
Depth of measured pressure data point.
Measured pressure at test flow rate.
Solution GOR of Oil
Free gas production from a gas cap or injection breakthrough. The
measured total GOR during the test (including the tank gas) must equal
GOR + GOR Free.
Rate of lift gas injection (gas lifted wells only).
Depth of operating valve (gas lifted wells only) .A good bottom hole
pressure match will not be obtained if an incorrect injection depth is used.
The Match Point Comment field is provided to allow the optional entry of notes to identify
the match data set. Examples would be test date, source of pressure data, comments on
test quality etc.
This input screen has a number of features to simplify data manipulation. The selection
buttons on the left hand side are used to select data points for further editing. Hold down
the Ctrl key and click the required buttons to select multiple points. Copy copies the
selected points into memory and onto the Windows clipboard. Click the selection button of
the desired destination and click Paste to copy the data to the new location. Insert shifts
the data down to make room for new entries. The Delete button deletes the selected
records. Data from this table can be copied to or from the Windows clipboard. Therefore,
test data can be read in from a Windows based spreadsheet by first copying it to the
clipboard, and then pasting it directly into the table.
Bad or inconsistent data points occasionally prevent the program obtaining a good match.
The Disable button causes a selected data record to be ignored in the matching process.
Disabled records are dimmed in the VLP matching screen. Disabled points can be reincluded in the matching process by first selecting the point and clicking on Enable. By
sequentially disabling suspect data points, potentially inaccurate test points can be
identified and eliminated from the match.
To compute the VLP match, click Match to display the VLP matching screen. Select the
correlations you wish to match or just click All to match all correlations. An example screen
is shown below:
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Figure 9-16
VLP Matching Screen
Click the Statistics button to examine the match parameters as shown on the example
screen below:
Figure 9-17
VLP Match Statistics
If necessary, match parameters can be edited or directly entered on this screen. This
should be done with extreme caution and only if previous work on similar wells has yielded
consistent match parameters or to apply match parameters for the same well in a different
PROSPER application.
PROSPER uses a non-linear regression to tune the VLP correlations to best match the
measured data. It does this by calculating a pressure traverse using a correlation and
determining the error between measured and calculated pressures. The gravity and
friction terms of the pressure loss equations are then adjusted and the process repeated
until the measured and calculated results agree within 1 psi, or 50 iterations have been
completed.
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Notes on Matching Parameters
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Parameter 1 is the multiplier for the gravity term in the pressure drop correlation
Parameter 2 is the multiplier for the friction term.
If PROSPER has to adjust Parameter 1 by more than +-10%, then there is probably
an inconsistency between the fluid density predicted by your PVT model and the
field data (rates/pressures).
Any model having a Parameter 2 outside the range 0.5 to 2.0 should be carefully
reviewed before proceeding.
In cases the PVT has been correctly matched, the greatest source of uncertainty in the
VLP calculation for oil wells is usually the hold-up correlation. PROSPER will attempt to
make a gravity component (Parameter 1) match by adjusting the hold-up correlation. If a
match is not obtained with a Parameter 1 more than 5% away from 1.0, the density is
adjusted. For single phase applications, no hold-up correction is possible, so any
significant deviation from 1.0 for Parameter 1 indicates a PVT problem.
If Parameter 2 requires a large correction, then it is likely that your equipment description is
in error, or the flow rates are incorrect. As the effect of a shift in the friction component on
the overall pressure loss is less than for the gravity term, a larger range in the value of
Parameter 2 is expected.
Once the matching process is complete, the match parameters will be shown alongside
each of the correlations that have been matched. Use the standard deviations and the
magnitude of corrections made to both parameters to aid your selection of matched
correlation.
Use the Correlation Comparison option of the Matching menu to compare the optimised
(matched) correlations with measured test data. To ensure that the process has been
successful, check that the matched VLP traverses plot close to the measured pressure
data points.
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PROSPER VLP matching provides a logically consistent means to adjust flow
correlations to reproduce field measured pressures. Combined with IPR matching,
PROSPER provides the means to create a robust well model that is capable of
reproducing observed pressures and rates. This is a necessary condition for
making accurate performance predictions and optimisation studies.
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9.6.2 IPR Matching
This feature allows the user to check the consistency of the flowing bottom hole pressure
data used in the VLP match and to adjust the IPR, if required, to match measured data.
Inconsistencies in test data resulting from e.g. changing reservoir pressures can be easily
identified. Clicking IPR from the VLP/IPR Matching screen will display the following IPR
Matching screen:
Figure 9-18
Adjust IPR
Click Calculate, and PROSPER will calculate the VLP for a range of rates and pressure at
the sand face for each of the active test points that have been entered on the VLP
Matching screen. Once this calculation is completed, click IPR and the IPR input screens
(Chapter 7) will be presented. For the first pass, accept the unmatched IPR data and
display plot. The VLP and test data will all be plotted on the same diagram as follows:
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Figure 9-19
VLP/IPR Plot
The errors between calculated and measured data are shown on the side of the plot. If the
test points are not consistent with the IPR model, the skin, reservoir pressure etc. can be
adjusted until a match is obtained. Inconsistent test data points will be easily identified on
this plot. Clicking Main returns you to the Adjust IPR screen. Matching both the VLP and
IPR to actual test data ensures that the PROSPER well model is capable of accurately
reproducing the currently known producing conditions.
Â
An IPR is required when automatic rate calculation is used for VLP or system
calculations. IPR data must be present before commencing a VLP/IPR Match.
Â
Hint for Vogel and multi-rate IPR. IPR Matching is a convenient way to correct
gauge pressures to intake node depth. For each test point, the Test Rate and
Test BHP are displayed on the VLP Matching screen. For a Vogel or Multi-rate
IPR, enter the rates and corrected BHP values.
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Gradient Match
This facility enables you to modify the existing correlations to fit to a measured pressure
gradient survey. It can also be used, as a quality control to identify which correlation
required the least adjustment to obtain a fit. From the Matching menu, select Gradient
(traverse) matching. The following screen will appear:
Figure 9-20
Gradient (traverse)
Matching Input
The first node pressure is entered in the Input Parameters section - do not include it in the
Match Data table. The Transfer button copies the measured gradient data to Correlation
comparison (Section 9.2). The same guidelines for GOR apply as for VLP/IPR Matching.
Enter the required data and click Calculate. The following will be displayed:
Figure 9-21
Gradient (traverse)
Matching Calculation
Select the correlations to be matched by clicking on them, then click Match to start the
matching routine. Parameter 1 is the correction factor applied to the gravity component of
pressure drop whilst Parameter 2 is the factor applied to the frictional element of pressure
drop. The match algorithm continues until the standard error is less than 1 psi, or 30
iterations have been performed. The adjusted correlation and measured pressures can be
visually compared by clicking Plot. A graph similar to the following is displayed:
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Figure 9-22
Gradient (traverse)
Matching Plot
The calculated pressure gradient can be inspected by clicking View. Click the Statistics
button to display the match parameters. Use the statistics and your knowledge of well
conditions and correlation performance to guide your choice of VLP correlation. Once a
correlation has been matched, the match parameters are appended to the correlation
name for all subsequent operations. Should it be necessary to adjust or clear the match
parameters, click the Reset button for a particular correlation, or use the Reset All button to
reset all correlations to their un-matched state.
Â
Best results are usually obtained by using VLP matching. Gradient matching
should only be used for specialised artificial lift applications and where many
pressure Vs depth data points are available.
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27 - 28
Surface Pipe Matching
This option is used to match measured data with the calculated pressure drop from the
wellhead to the manifold. This option is useful only if surface equipment has been entered
in System  Equipment. Select Surface pipe matching from the Matching menu to display
the following input screen:
Figure 9-23
Surface Pipe
Matching
Input
Â
The user can now use the ‘Correlation Comparison’ button to transfer the
selected pipeline test data to the pipeline correlation comparison section. The
procedure is:
•
•
•
Click on the button to the left of the pipeline test data that we wish to
perform correlation comparison on.
Click on the ‘Correlation Comparison’ button
PROSPER will bring us to the pipeline correlation comparison screen and
at the same time, populate the correlation comparison screen with the
selected pipeline test data.
Enter measured manifold and tubing head pressures for a range of rates and click Match to
enter the calculation screen. Select the correlations to match in the same manner as for
Gradient matching. All editing and calculation controls operate as described under
Gradient matching. Once the matching is complete, click OK to return to the main menu.
Â
If the system description has no elevation difference between the wellhead and
manifold, there can be no gravitational component of the correlated pressure
drop. Therefore, Parameter 1 cannot be optimised, so it remains at the default
value of 1.0 for such cases.
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9.9
Vertical Pipe Parameters
This option allows the match parameters for the tubing pressure drop correlations to be
accessed. They can be reset to their un-matched values, or new values entered directly.
9.10 Surface Flow line Parameters
This option allows the match parameters for the surface piping pressure drop correlations
to be accessed. They can be reset to their un-matched values, or new values entered
directly.
9.11 Correlation Thresholds
This option allows the user to specify alternative correlations to use for tubing or pipeline
when the angle (from the vertical for tubing and from the horizontal for pipelines) exceeds a
user-specified threshold value. This option is useful for modelling the riser for a long sub
sea tieback or for a highly deviated surface pipeline. Enter the appropriate angles and
correlations. Select Yes to the question Use Threshold Angle to enable the feature. When
enabled, the calculation screens will indicate that this option is active.
Figure 9-24
Correlation Threshold Input
Screen
PETROLEUM EXPERTS LTD
10 Calculation Menu
This chapter describes the calculation methods available and how to set up PROSPER to
calculate system solution rates, sensitivity cases, generate lift curve tables etc. The menu
options available are:
Â
Inflow
This option calculates tubing intake (IPR) curves and bottom hole flowing
pressure (BHFP). This allows you to quickly calculate a wide range of flowing
pressure sensitivities without the need to calculate the system solution rate. This
is especially convenient for e.g. frac program design, gravel pack design,
perforation programming.
System
This option will calculate both the tubing outflow (VLP) and tubing intake (IPR)
curves and determine the system operating rate and bottom hole flowing
pressure (BHFP). It also allows you to perform sensitivity analysis with a wide
range of variables. Sensitivity plots can easily be generated.
Gradient
This option enables you to generate gradient plots. If the correlations have been
matched, the gradients will be generated using the tuned correlations.
VLP (tubing curves)
This option enables the generation of VLP curves that can be exported for use in
various commercial reservoir simulators and Petroleum Experts' MBAL material
balance program.
VLP (tubing curves) - 4 Variables
This option allows generation of tubing lift curves for artificially lifted wells.
Choke Performance
This is a convenient calculator for flow rates, pressure drop or choke settings.
Generate for GAP
Allows you to automatically calculate well performance data for gas lifted or
naturally flowing wells for use in Petroleum Experts’ GAP production system network
modelling program.
Â
Â
Bottom Hole Pressure from Wellhead Pressure: This option allows you to
calculate flowing bottom hole pressure from the wellhead pressure. This method
is only available when using the Pressure and Temperature and Rough
Approximation options.
When the Enthalpy Balance temperature model is being used, different
calculation menus are presented. The calculation menus for predicting pressure
only and the rough or improved approximation temperature model are virtually
identical. The selection of lift method and IPR model also affects the available
sensitivity variables and specialised calculations.
2 - 46
CHAPTER 10 - CALCULATION MENU
10.1
Calculation Options For Predicting Pressure Only or
Rough/Improved Approximation Temperature Cases
10.1.1
Inflow (IPR)
Select Calculation  Inflow (IPR) when you want to calculate sensitivities for completion
options and reservoir variables without the need to calculate the VLP and system solution.
The range of Inflow variables available depend on the particular IPR model entered in
System  Inflow performance. To calculate the inflow pressures, click Calculate  Inflow
(IPR) and you will be prompted to select a rate method. Select one of the following:
•
Automatic Linear
In previous versions it used the AOF (absolute open flow) from the System  Inflow
Performance and selects 20 evenly spaced rates up to the AOF as calculation
rates.
Currently, it works out the AOF for various sensitivity variables entered and for each
AOF creates 20 evenly spaced rates for sand face pressures calculations.
•
Â
•
Automatic Geometric
As for Automatic Linear, it works out the AOF for various sensitivity variables
entered and for each AOF creates 20 rates for sand face pressures calculations,
except the rates are spaced more evenly near zero.
Use this option when evaluating minimum stable flow rates.
User selected
You can either enter a table of up to 20 rates directly, or PROSPER will Generate
them for you. Click Generate from the User Selected rate entry screen and the
following screen will be presented:
Figure 10-1
User selected rates
Generation
Enter values for the first and last rates in the table plus the number of entries required.
Depending on the selection of Linear or Geometric spacing, PROSPER will calculate the
required rate table.
Â
User selected rates can be useful when using the AOF is inappropriate for the
range of sensitivity variables to be considered.
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Click OK, then enter values for up to 3 sensitivity variables as on the following screen
example:
Figure 10-2
IPR Sensitivity Variables
Click an Enter Values button and enter values for the sensitivity variables by hand, or click
Generate to have PROSPER calculate a range of values as follows:
Figure 10-3
Generate Sensitivity Values
The Combinations button can be used to enter particular scenarios to calculate. Refer to
Sensitivity Combinations in Section 10.1.2 for more details.
Once you have set up the Inflow sensitivity variables, click OK  Calculate to calculate the
IPR pressures. Click Plot to display a screen similar to the following:
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CHAPTER 10 - CALCULATION MENU
Figure 10-4
IPR Calculation Results
Â
On this plot by pressing on the VARIABLES option on the menu bar, you can get
a display of all the variables that have been calculated during IPR calculations,
like skin, dP skin etc. These can be plotted as well.
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System (VLP + IPR)
The Calculation screen enables you to choose correlations for surface equipment and
down hole equipment as well as select a rate method. Top node pressure and water cut to
use for the calculation should be entered also.
Figure 10-5
System Calculation Setup
The rate methods available are:
1. Automatic Linear
The program uses the AOFP found in the IPR section and creates 20 intermediate
rates between zero and AOF.
2. Automatic Geometric
The program uses the AOF found in the IPR section and creates 20 rates between zero
and AOF with rates spaced more closely together at low rates.
3. User Selected
If this option is selected, you will be asked to enter the rates you desire, or click
Generate to have PROSPER generate a range of values for you.
Â
An IPR is required for both Automatic rate methods. For wells having very high
AOFs (e.g. horizontal wells) the well rate is determined mainly by the tubing size.
Manual rate selection may give better results in such cases.
Enter the surface equipment and vertical lift correlations best suited for your data, and then
select the rate method. Matched PVT and VLP correlations will be used where matching
has been carried out. Click OK to display the Sensitivity Variables screen.
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CHAPTER 10 - CALCULATION MENU
10.1.3
Left - Hand Intersection for VLP/IPR curves
Normally VLP/IPR intersections that occur when the tubing pressures are declining (on the
LHS) are considered to represent unstable flow and are usually ignored.
When Gas Coning occurs however the GOR is changing constantly for different rates and it
is possible to have two solutions and for the LHS intersection to represent stable flow.
Figure 10-6
Left hand intersection
10.1.3.1
Sensitivity Variables Screen
Three variables can be entered simultaneously. The range of choices is determined by the
Options and System input parameters. Each variable can have up to 10 values. Below is
an example of the variables selection screen:
Figure 10-7
Sensitivity Variables Input
The calculations will be ordered so that only the IPR will be recalculated where possible.
This can save a great deal of calculation time.
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Tubing diameter sensitivity is only available under Variable 3.
When tubing diameter is entered as a sensitivity variable, the following screen is used to
input the range of nodes over which the sensitivity is calculated:
Figure 10-8
Diameter Variable Range
Normally tubing diameter should not be varied in the casing below the tubing shoe. This
option is also useful for determining e.g. the effect of increasing tubing size above a safety
valve while keeping the diameter of the rest of the tubing string diameter constant.
Sensitivity variable values can be entered in any order. To improve the readability of the
sensitivity plots, the variable values are sorted in ascending order before the sensitivities
are calculated. Only the sensitivity variables relevant to the chosen system will be
available. For example, if a well is gas lifted you will be given the option of gas injection
rate as a variable. This option will not be available if the well is naturally flowing.
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CHAPTER 10 - CALCULATION MENU
10.1.3.2
Generating Sensitivity Values
Click Enter Values to display a table containing the sensitivity variable values. You can
enter values by hand or Generate them. Refer to Inflow above for more details on how to
Generate lists of values.
10.1.3.3
Sensitivity Combinations Screen
This feature provides an alternative way to calculate sensitivities. Either the Combinations
or Variables screens can be used to set up tables of sensitivity variables. The Variables
method is best suited to design applications where a number of hypothetical cases must be
run. The Combinations option allows the user to enter specific combinations of field data
(or hypothetical cases) then allow the program to calculate the unknowns. An example of a
Combinations screen is shown below:
Figure 10-9
Sensitivity Combinations
Input
Â
If no liquid rates are entered, the program uses the current list of rates (either
internally calculated or user input) and calculates the solution for the combination
of sensitivity variables for each of up to 10 cases.
If liquid rates are entered in the Combinations screen, these take precedence.
The program will then find the VLP and IPR pressures for each combination of
sensitivity variables.
Note that a solution rate is not computed in this case.
Once sensitivity values have been entered in either the Combinations or Variables screen,
click OK to display the calculation screen. Sensitivity values temporarily overwrite variable
values that have been entered on other screens. For example: Pressure at first node,
water cut.
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10.1.3.4
9 - 46
Calculation Screen
Click Calculate to start the system solution calculations. This may take a while, so please
be patient. A calculation screen example is shown below:
Figure 10-10
Calculation System
The components of the calculated IPR pressure can be inspected by scrolling to the right
of the calculation screen. The liquid rate, oil rate and bottom hole pressure for each
combination of sensitivities can be accessed by clicking the up and down arrows in the
boxes next to the variables.
Details of Solutions
To examine the solution in more detail, click the Solution details button. Individual solution
points can be viewed by clicking on the arrow buttons located beside each sensitivity
variable. Outflow or Inflow solutions can be viewed as shown in the following sample
screen:
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Figure 10-11
Calculation
System Solution
Details
Plotting Results
The results can be plotted by clicking Plot. The System plot will appear as follows:
Figure 10-12
System Solution Plot
The system plot summarises all the calculations. Each VLP and IPR curve is identified by
up to 3 numbers posted beside them. The variable names and the corresponding number
labels are shown in the panel to the right of the plot. In the above example, Curve 1,0,0 is
for 40% water cut, 200 psi first node pressure and 2.992 inch tubing. As none of the
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variables change the IPR in this example, the IPR curves for each case are identical and
overlay.
To plot the solution rates and pressures versus the selected variables, click Sensitivity and
a sensitivity plot will be displayed. To select sensitivity variables to plot, click Variables and
make your selection on the following screen:
Figure 10-13
System Sensitivity
Variables
The Sensitivity screen allows you to choose X- and Y-axis variables. Click OK to view the
Sensitivity plot. The program automatically plots the sensitivity values of the X-axis
variable. If variable Combinations have been used, the sensitivity cases will be
automatically plotted.
Figure 10-14
System Sensitivity Plot
The pressure gradient for any particular solution rate can be calculated by clicking Sens
PvD (Sensitivity Pressure vs. Depth).
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Performing Gradient Calculations for a Given Solution
Set up the case to calculate on the screen as shown below. Select the combination of
variables corresponding to your chosen solution and click OK to access the gradient
calculation screen.
Figure 10-15
Sens PvD Setup
From the gradient calculation screen, click Calculate to generate the gradient. The results
are displayed on the following screen example:
Figure 10-16
Sens PvD
Results
Click Plot to display the Gradient vs. TVD or Measured Depth:
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Figure 10-17
Sens PvD Plot
Once the calculations have been done the results can be saved. The .ANL file will contain
all the input data and plots that have been generated. The .OUT file will contain the
calculated results. Click Variables on the plot screen to select which variables to plot.
Figure 10-18
Plot Variables Selection
By clicking the Extended button, a greater range of plot variables can be accessed.
Virtually any combination of computed results can be plotted against each other.
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Figure 10-19
Extended Plot Variables
Return to the standard choice of plot variables by clicking the Original button.
The plots are held in memory until overwritten by a new set of calculations. Plots can also
be displayed or output by selecting Plot from the main menu. The Units menu can be used
to change the display units if required.
Special Note for ESP and HSP Applications
When calculating a System solution for an ESP or HSP equipped well, clicking the Pump
button on the Solution Point screen lists details of the pump solution such as pump intake
pressure etc. (See example pump solution in the screen below)
Figure 10-20
ESP Solution Point
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Clicking Plot on the pump solution screen displays the sensitivity solutions plotted over the
pump characteristic curves. As shown by the example screen below, the effects of the
sensitivity variables on the pump operating point can be readily evaluated.
Figure 10-21
ESP Solution Plot
This plot is a powerful tool for evaluating how an ESP design can accommodate future
changes in well conditions.
Â
All pump (both ESP & HSP) designs should be validated by calculating
sensitivities and ensuring that efficient operation at the design rate can be
achieved over the entire range of expected well and pump efficiency
conditions.
For pump (both ESP & HSP) equipped wells, the Sens. PvD gradient calculation shows the
pressure increase across the pump. An example gradient plot is shown below:
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Figure 10-22
ESP Sens. PvD Plot
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10.1.4
17 - 46
Gradient (Traverse)
The Calculation  Gradient (traverse) feature allows the user to calculate flowing pressure
gradient curves at a specified flow rate. These curves can be compared with published
pressure traverse curves or actual well data. Pressure traverses can also computed for
combinations of sensitivity variables. The effect of changing tubing sizes, SSSV I.D. etc.
can be evaluated visually by plotting the gradient results.
To commence the Gradient calculation, cl
18 - 46 CHAPTER 10 - CALCULATION MENU
Figure 10-24
Gradient Traverse
Calculation
Click Calculate to compute flowing gradients for all sensitivity cases. Once the calculations
have been completed, the results tables can be inspected by clicking the respective
variable arrows until the desired variable combination is visible. A plot of the gradient
results similar to that below can be displayed by then clicking the Plot button:
Figure 10-25
Gradient Traverse Plot
Gradients can be plotted for the well and flow line separately or combined on the one plot.
Extended plot options are available as outlined in Section 10.1.1.
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10.1.5
19 - 46
Gradient (Traverse)-Modified Turner Equation
Used to determine unstable flow regions in Gas or Condensate wells with liquid production.
Has been found to be not necessarily reliable. The original Turner Constant was 20.4. It
has been found (using Petroleum Experts 4) that 2.04 gives much more reliable results in a
wide range of examples. This constant can be changed by the user.
Figure 10-26
Modified Turner
Equation
Classical Turner Equation
σ ( ρl − ρ g )
Vt = 20.4
ρ
σ - Surface Tension (dynes/cm)
1
4
1
g
1
4
2
ρl - Liquid Density (lbm/ft 3 )
ρ g - Gas Density (lbm/ft )
3
When gradient traverse calculations are performed scrolling the screen the values are
display, using the button indicated as Sand the user will be able to change the Turner
constant.
Figure 10-27
Gradient traverse
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10.1.6
Erosional Velocity Calculations for Sand Laden Fluids
When gradient traverse calculations are performed the program will estimate the
correspondent value of erosional velocity.
Erosion can be caused by the repeated impact of solid particles on tubings and pipelines.
To avoid this we attempt to estimate the velocity at which erosion will occur. Normal
practise is to use equation of API 14 E. This can be unreliable especially for clean
production where the limiting value of C (125) can be too restrictive. In practice, values of
1000 for C have been recorded in pipes where no erosion has been detected.
Figure 10-28
Clasical equation
of Erosional
Velocity
Ve =
C
ρm
Ve - Fluid Erosion Velocity (ft/sec)
C - Empirical constant (C-Factor)
ρ m - Mixture Density (lbm/ft3 )
A Conoco paper (An Alternative to API14E Erosional Velocity Limits for Sand Laden Fluids)
challenges API14E on the basis that it can be very conservative for clean service and is not
applicable for conditions where corrosion or sand are present. It proposes a simple
alternative approach that has been verified by a comparison with several multi-phase flow
loop tests that cover a broad range of liquid-gas ratios and sand concentrations. Values of
S for different components are proposed in the paper
Figure 10-29
New eorsional
velocity
calculations
Ve = S
D ρm
W
S - S Factor (depends on pipe geometry)
D - Pipe Diameter (mm)
ρ m - Mixture Density (lbm/ft
3)
W - Sand Production (Kg/day)
After gradient calculations are performed scrolling the screen the value of erosional velocity
can be found.
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Figure 10-30
Gradient traverse
To find out the correspondent constants to estimate the erosional velocities based on the
new approach the option Sand can be used.
Figure 10-31
Gradient traverse
Â
In PROSPER, we calculate and display the C value and it is the responsibility of
the User to work out whether for this C value, erosion will occur or not depending
upon the expected operating conditions.
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10.1.7
VLP (Tubing) Curves – 3 Variables
An important PROSPER application is generating tubing lift curves for use in reservoir
simulation. To generate lift curves click Calculation  VLP (tubing curves)  3 Variables...
Select appropriate surface pipeline and VLP correlations on the input screen. If VLP
matching has been carried out, the matched correlations will be available. Click OK to
access the calculation screen as shown below:
Figure 10-32
VLP Calculation Setup
If an IPR is available, the rates for the VLP calculations can be automatically generated.
To calculate VLPs for specified rates, or when no IPR is available, user selected rates can
be entered in a table as shown above.
When User Selected rates are used, you can enter rates in terms of Liquid, Oil or Gas. The
results will be given in terms of the specified rate type, but depending on the type of well,
PROSPER will first convert the rates to equivalent oil or gas to calculate the VLP pressure.
This feature can be used when preparing lift curves for high GOR oil wells. Remember
when using gas rates, that increasing the water cut will also increase the liquid production
rate. Extreme VLP pressures can easily result.
Click OK to access the Variables screen and set up the required sensitivity variables. To
generate lift curves for e.g. ECLIPSE, the VLP is generally calculated for the following
sensitivity variables:
• Variable 1:
Pressure at first node
(Usually THP)
• Variable 2:
Water cut
(Water to gas ratio for gas wells)
• Variable 3:
Gas Oil Ratio
(Use GOR)
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An example calculation variables screen for generating lift curves is shown below:
Figure 10-33
VLP Sensitivity Variables
Select the variables required by your external application and enter a list of values for
each. Click OK to access the calculation screen then click Calculate to generate the lift
curves. An example lift curve calculation screen is shown below:
Figure 10-34
VLP Calculation
Results
The calculated VLP results can now be exported to a number of external application
programs. Once the calculations have been completed, click Plot to visually check the
results and Export to access the export selection screen.
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At present, PROSPER supports the following export formats:
Figure 10-35
VLP Export Options
(3 Variables)
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Schlumberger - ECLIPSE
Welldrill - SIMCO 3
ExxonMobil - Pegasus
Petroleum Experts - MBV
SSI – COMP4
FranLab – FRAGOR
SSI – COMP3
LandMark - VIP
Roxar - MORE
Petroleum Experts – GAP/MBAL
Shell - MORES
FranLab - ATH
BP Amoco - GCOMP
Chevron Texaco-CHEARS
ExxonMobil-EMPOWER
.ECL
.SIM
.MOB
.MBV
.CP4
.FRA
.CP4
.VIP
.MOR
.TPD
.MRS
.ATH
.GCM
.CHE
.Hyd
PROSPER appends the export file with a suffix corresponding to the selected file format as
shown in the table above. Depending on the export format selected, you will be prompted
for a file name and additional data such as table number, flow table I.D. etc. Refer to your
simulator documentation for further details.
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25 - 46
Simulators have varying requirements for VLP sensitivity variables. If the
correct variables have not been selected for calculation, PROSPER may not be
able to correctly export the VLP file. Pay particular attention to GLR and GORs.
To model artificially lifted wells, reservoir simulators require 4 variable lift curves.
Refer to Section 10.1.4.
A Note on preparing lift curves for ESP equipped wells
There are 2 options available for generating ESP lift curves:
•
•
Tubing Curves (standard)
Lift curves for simulators
The standard option prompts you to enter the bottomhole pressure. PROSPER calculates
from the deepest node to the pump. The pump head for the given frequency, water cut etc.
is calculated to find the pump discharge pressure. PROSPER then determines the PVT of
the oil above the pump after accounting for possible gas separation and calculates the
pressure traverse above the pump to find the top node pressure for each required
production rate point.
Simulators require tables of rates and BHPs ordered by THP. The Lift curves for
simulators option allows input of Top Node pressure, water cut, operating frequency etc.
PROSPER iterates to find the pressure at the deepest node (VLP) given the top node
pressure. In both cases, the VLP is the bottom hole pressure for the specified producing
conditions.
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10.1.8
VLP (Tubing) Curves - 4 Variables
To model artificially lifted wells, an additional sensitivity variable is required. This option
allows calculation of four variable sensitivities (provided the total number of sensitivity
combinations is less than 10,000) and export of lift curves for gas lifted and ESP or HSP
equipped wells. Set up, calculation and export of 4 variable tubing curves follows the same
procedures as described above (Section 10.1.3) for regular tubing curves. No automatic
rate calculation is provided - User selected rates must be entered. Oil, Liquid or Gas rates
are supported.
PROSPER can re-order the variables to suit the selected export file format, but you must
first ensure that the lift curves have been calculated for variables that your application
understands. At present, gas lifted VLP curves can be exported to the following external
applications:
Figure 10-36
VLP Export Options
(4 Variables)
•
•
•
•
•
•
•
Schlumberger - ECLIPSE
Petroleum Experts - MBV
FranLab - SCORE
SSI - COMP3
LandMark - VIP
Petroleum Experts – GAP/MBAL
Shell - MORES
PETROLEUM EXPERTS LTD
.ECL
.MBV
.SCO
.CP3
.VIP
.TPD
.MRS
CHAPTER 10
•
•
•
•
FranLab - ATHOS
BP Amoco - GCOMP
Chevron Texaco-CHEARS
ExxonMobil-EMPOWER
27 - 46
.ATH
.GCM
.CHE
.Hyd
An example of a 4 variable VLP calculation for a gas lifted well is shown on the following
screen:
Figure 10-37
4 Variable VLP Calculation
Setup
A Note on Preparing Lift Curves
Because of the large number of calculations that must be performed, preparing lift curves
can be a time consuming process, so it is important to obtain good results at the first
attempt. Due to the extreme range of flowing conditions that must be covered by the lift
curve tables, problems with the computations are occasionally encountered. The following
discussion covers some of the points that should be addressed when planning a lift curve
calculation run.
•
Finding a VLP correlation that performs well for the entire range of rates that must be
spanned by the lift curves can be difficult. Some correlations handle slug flow (e.g.
Hagedorn Brown) but fail in the mist flow regime e.g. after injection gas breakthrough.
Care must be exercised in selecting correlations to ensure that the wells are properly
represented over the most important range of flow rates to be modelled in the
simulation.
•
Problems can occur for extremes of water cut and GOR. e.g. if the oil production rate
is fixed, the liquid production rate becomes very high as the water cut approaches
100%. To maintain lift in a high water cut well, a specific GLR is required. If injection
gas is expressed in terms of GOR injected, the required GOR approaches infinity as
the water cut approaches 100%. A huge range of GOR injected is therefore required to
model the well. The use of liquid rates and injection GLRs in oil well lift curve tables is
recommended to avoid such problems.
•
Depending on the particular simulator used, it is not possible to pass the variable
names or units between programs. Users are reminded to ensure that the sensitivity
variables and output units used in PROSPER are consistent with those expected by the
simulator. In particular, gas units (MMscf Vs Mscf), gas lift (GLR Vs Gas Lift Injection
Rate) and rates (Oil Vs Liquid) should be checked.
•
PVT correlations should only be used within the range of temperature and pressure for
which they were derived. Occasionally, combinations of tubing curve variables require
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an excessive VLP pressure to pass the specified rate, and the PVT correlation may fail.
Occasionally, PROSPER may halt rather than continuing the calculation with a fictitious
result. You may have to revise the range of variables or select a different PVT
correlation in such cases. Beware of chokes and restrictions in the equipment
description that may result in excessive calculated pressure drops. If using externally
generated PVT tables, they must span the entire calculation range. Make sure that
GOR is constant above bubble point, and the FVF is decreasing.
•
Provided you enter the rates by hand, it is not necessary to enter an IPR to calculate
VLP tables. PROSPER needs the IPR to find the calculation rates if an Automatic rate
method has been selected. Automatic rate selection is not available for 4 Variable VLP
calculations.
•
Oil well lift curves can now be calculated in terms of gas rates for specialised
applications. Make sure that the liquid rates that result from your choice of GOR, water
cut etc. does not result in impossible liquid rates. Be especially careful when there are
chokes and restrictions in the system.
A Note on preparing lift curves for ESP equipped wells
There are 2 options available for generating ESP lift curves:
• Tubing Curves (standard)
• Lift curves for simulators
The standard option prompts you to enter the bottom hole pressure. PROSPER calculates
from the deepest node to the pump. The pump head for the given frequency, water cut etc.
are calculated to find the pump discharge pressure. PROSPER then determines the PVT of
the oil above the pump after accounting for possible gas separation and calculates the
pressure traverse above the pump to find the top node arrival pressure for each required
production rate point.
Simulators require tables of rates and BHPs ordered by THP. The Lift curves for
simulators option allows input of Top Node pressure, water cut, operating frequency etc.
PROSPER iterates to find the pressure at the deepest node (VLP) for the given the top node
pressure. In both cases, the VLP is the bottom hole pressure for the specified producing
conditions.
Â
VLP lift curves for simulators or Petroleum Experts’ applications (GAP and
MBAL) can be batch generated for groups of wells by PROSPER under the
control of PRODMAN (distributed with PROSPER) or from GAP. Refer to
the PRODMAN or GAP documentation for details.
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10.1.9
29 - 46
Choke Performance
This is a general purpose choke performance calculator. Only PVT data input is required
to calculate flow rates given the choke size and pressures, choke setting to achieve a
specified flow rate etc. To access the choke performance calculator, click Calculation 
Choke Performance and the following selection screen may be displayed (depending on
the Choke Method selected):
Figure 10-38
Choke
Performance
Calculator
Calculation Options
Select your required calculation option from the following:
• Predict Mass Flow Rate
PROSPER determines the flow rate for specified choke opening and pressures
• Predict Pressure Drop
PROSPER calculates the pressure drop across a specified choke opening at a given
flow rate and pressure
• Predict Choke Valve Setting
PROSPER finds the choke size for a specified rate and upstream pressure.
Choke Method
Select a choke calculation method from the following options:
• Petroleum Experts
This is the same method used to calculate pressure drops down hole for SSSVs
and restrictions. It should be used for the majority of applications.
• HYDRO
There are 3 distinct methods for modelling specific choke equipment. Until
performance testing is completed and documentation issued, these choke methods
should not be used.
•
ELF
A model based on Perkin’s (SPE 206333) approach along with discharge
coefficients determined by the author (Stephane Rastoin of ELF Aquitaine at
TUALP). This is also the recommended method used to calculate pressure drops
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30 - 46 CHAPTER 10 - CALCULATION MENU
down hole for SSSVs and restrictions.
applications.
It should be used for the majority of
Enter the following data:
•
•
•
•
•
•
•
GOR
Water Cut
Inlet Pressure
Inlet Temperature
Outlet Pressure
Outlet Temperature
Choke setting
This value overrides the GOR entered on the PVT data screen.
Pressure upstream of the choke
Upstream temperature
Downstream pressure
Downstream temperature
Orifice size
Click Calculate, and PROSPER will calculate the liquid and mass flow rates Similar screens
are used to enter data for the dP and Choke Setting prediction options. For critical flow
conditions, it may take some time for the calculation to converge.
10.1.10 Generate for GAP
This option is used to calculate well performance solutions for Petroleum Experts Limited's
General Allocation Program (GAP). PROSPER can be run from within GAP in a batch
mode for generating performance curves for groups of wells or independently of GAP by
selecting this option.
PROSPER will automatically calculate solutions for gas lifted or naturally flowing wells. If
the solutions are then saved in a .OUT file, GAP can pick up the data required to calculate
performance curves at a later time. For more information, refer to the GAP documentation.
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10.2
31 - 46
Calculation Menu – Rough Approximation Cases Only
10.2.1
Bottom Hole Pressure from Wellhead Pressure
This option allows you to calculate flowing bottom hole pressure from the wellhead
pressure. This method is only available when using the Pressure and Temperature and
Rough (or Improved) Approximation options.
It requires gas, water and oil rate information as well as wellhead temperature and
pressure. This information can be in one of several formats (e.g. Gas Rate or GOR, etc.)
and the correct format for your data can be selected at the top of the appropriate columns.
If you change the data type in a particular column while there is data already in that
particular column, then the data will be converted to the new type. If there is insufficient
data to convert all of the data in the column (for instance if there is data missing in one of
the dependent columns for one of the rows) the operation will not be carried out and you
will be warned of the problem. In the case of gas lifted wells the gas lift gas rate is required
and in the case of ESP lifted wells the pump frequency must be entered.
10.2.1.1
Data Input
Figure 10-39
BHP from
WHP
The table is quite large allowing you to start off with up to 16000 rows of data which is
automatically expandable up to 32000 rows. The data can be scrolled with the scrollbar at
the right hand side of the screen.
Appropriate vertical lift and surface pipe correlations can be selected at the bottom of the
screen.
Selecting the import button allows you to bring in data from an outside source. Table data
can be saved to file using the export button and plots using either time or the log of time
can also be viewed and exported using the plot feature. Within the plot screen data can be
enabled or disabled point by point or in a block manner by using the right hand mouse
button.
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Figure 10-40
BHP from WHP plot
Data can be ordered with relation to time by using the sort button. This will also remove
any blank rows between data in the table.
The following is a description of the buttons:
Calculate
Starts the calculations running. The progress of the calculations can be
seen on the screen as the table scrolls to the current row being calculated.
Import
Calls the Petroleum Experts importing system allowing the import of data from
text files or ODBC compliant databases.
All
Selects or deselects all the rows in the table depending on their last
selection state. This includes the rows not currently visible and is a good
way of clearing the selection states of all table rows.
Cut
This cuts all selected rows to the clipboard. Empty rows are left in the place
of the rows cut. This can also be achieved by using the standard Windows
keyboard shortcuts, as can the copy and paste functions.
Copy
This copies all selected rows to the clipboard. The rows are left as they
were.
Paste
This pastes the current clipboard contents into the table at the selected
rows.
Insert
This inserts a blank row at the selected rows.
Delete
This deletes all selected rows to the clipboard. The selected rows are
removed from the table and the surrounding rows are move to fill the space
left.
Enable
This enables the selected rows and determines whether they are included in
the calculations or not. The default is that all rows are enabled.
Disable
This disables the selected rows. Disabled rows are not included in the
calculations and are seen as being greyed out in the table. Disabled rows
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are shown with a different symbol when plotted but are still visible. This is
necessary to make full use of the enabling/disabling facilities in the plot
screen.
Export
This calls the Petroleum Experts export facility, which allows you to send data to
file, printer or the screen.
Sort
This sorts the table in the order of increasing time.
Plot
This calls the plotting screen. This displays the wellhead pressure, the
calculated bottom hole pressure and the appropriate rate for the given fluid.
10.2.1.2
References
SPE PAPER 22870
Modelling of Well bore Heat Losses in Directional Wells Under Changing Injection
Conditions
K Chu and S Thakur, Amoco Production Co.
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10.3
Calculation Menu - Enthalpy Balance Temperature Model
Only
The Predicting Pressure and Temperature analysis option can be used to generate
temperature and pressure profiles in producing wells.
This rigorous thermodynamic model considers heat transfer by conduction, radiation,
forced and free convection. Heat transfer coefficients are calculated using thermodynamic
data held in a user-definable database. The temperature prediction calculations are
transient, allowing sensitivities against flowing time to be run for both wells and pipelines.
This temperature model requires considerably more input data and computation time for
either Predicting Pressure Only or the Rough or Improved Approximation temperature
model. Enthalpy Balance should be applied only when the desired result is the
temperature. The additional computational effort cannot be justified for pressure loss
calculations.
Both pressure and temperature losses across chokes and restrictions are accounted for. A
theoretical outline of the Enthalpy Balance model is given in Appendix C.
Temperature prediction is useful for generating temperature profiles in:
•
•
•
•
•
pipelines
sub sea wells
high pressure/temperature exploration wells
predicting temperature/pressure profiles to help predict wax/hydrate deposits.
accounting for Joule-Thompson effects
PROSPER 's Enthalpy Balance temperature model is one of the most accurate temperature
prediction methods available.
Â
The Enthalpy Balance temperature calculation must commence from a known
condition. This is usually the reservoir pressure and temperature. As a
consequence, calculating from a downstream node (unknown temperature) to an
upstream node (known temperature) is not meaningful.
For injectors,
calculations commence from the known wellhead pressure and temperature.
To reflect the range of calculations possible when using the Enthalpy Balance temperature
model, the following options are available in the Calculation menu:
Constrained System (IPR + VLP)
PROSPER calculates the actual production conditions for a known wellhead pressure. The
sand-face conditions are taken as per the IPR.
Constrained VLP (Tubing Curves)
PROSPER calculates the flowing tubing curves for a known sand face flowing temperature
and a wellhead pressure.
UnConstrained System (IPR + VLP)
PROSPER calculates the surface pressure and temperature for a specified production rate.
UnConstrained VLP (Tubing Curves)
PROSPER calculates the surface pressure and temperature for a specified rate and bottom
hole pressure.
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UnConstrained Gradient (Traverse)
Calculates the temperature and pressure profile downstream of a specified pressure and
temperature for a given rate.
Match Parameters
Allows entry of match parameters for surface flow lines and well tubing.
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10.3.1
The Match parameters that may be entered into an Enthalpy balance model need
to have been generated in a rough/ improved approximation model.
Constrained System
Calculate  Constrained System (IPR + VLP) is used to calculate the production rate
required, given the reservoir pressure and temperature to deliver the constrained pressure
(entered by the user) at surface.
Â
The input is:
•
•
•
Well head/ first node pressure.
Water Cut
Time since start of production
The output is:
•
•
•
Well head temperature
Production Rate
Sand-face pressure.
The calculation is an iterative one and the inlet conditions are changed till an
acceptable top node condition is achieved.
The IPR input in the System menu is used to determine the flowing bottom hole conditions.
An example Constrained System input screen is shown below:
Figure 10-41
Constrained System Input
Enter the Constrained (Top) Node Pressure, Water Cut and Time Since Production
Started. Select suitable Surface Equipment and Vertical Lift correlations.
Click OK to display the sensitivity variables input screen.
Click OK to display the calculation screen.
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Figure 10-42
Constrained
System
Calculation
Click Calculate to start the calculations. The results can be inspected by clicking the
Solution button as shown below.
Figure 10-43
Constrained
System Solution
Screen
Calculate the flowing gradient for any particular solution by clicking on Sensitivity
PvD.
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10.3.2
37 - 46
Constrained VLP
Calculate  Constrained VLP (Tubing Curves) is used to calculate the tubing Curves, given
the reservoir pressure and temperature to deliver the constrained pressure (entered by the
user) at surface.
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The input is:
•
•
•
•
•
Well head/ first node pressure.
Bottom-hole / Entry fluid temperature
Water cut
Time since start of production
Rate values for calculation
The output is:
•
•
Well head temperature
Sand-face pressure.
The calculation is an iterative one and the inlet conditions are changed till an
acceptable top node condition is achieved.
The IPR input in the System menu can be used to determine the flowing bottom hole
conditions or the user may enter a selection of rates. An example input screen is shown
below:
Figure 10-44
Constrained VLP Input
Click OK to display the sensitivity variables input screen. Select suitable VLP and surface
equipment correlations, enter the water cut, the time since production started and a range
of production rates. Click OK to display the calculation screen.
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Figure 10-45
Constrained
VLP Calculation
Screen
Click on Plot to view a graphical representation of the calculation as shown below
Figure 10-46
Constrained
VLP Plot
The calculated VLP results can now be exported to a number of external application
programs. Once the calculations have been completed, click Plot to visually check the
results and Generate Lift Curve File to access the export selection screen.
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At present, PROSPER supports the following export formats:
Figure 10-47
Constrained VLP
Export Options
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Schlumberger - ECLIPSE
Welldrill - SIMCO 3
ExxonMobil - Pegasus
Petroleum Experts - MBV
SSI – COMP4
FranLab – FRAGOR
SSI – COMP3
LandMark - VIP
LandMark - MORE
Petroleum Experts – GAP/MBAL
Shell - MORES
FranLab - ATH
BP Amoco - GCOMP
Chevron Texaco-CHEARS
ExxonMobil-EMPOWER
.ECL
.SIM
.MOB
.MBV
.CP4
.FRA
.CP4
.VIP
.MOR
.TPD
.MRS
.ATH
.GCM
.CHE
.Hyd
PROSPER appends the export file with a suffix corresponding to the selected file format as
shown in the table above. Depending on the export format selected, you will be prompted
for a file name and additional data such as table number, flow table I.D. etc. Refer to your
simulator documentation for further details.
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10.3.3
Simulators have varying requirements for VLP sensitivity variables. If the
correct variables have not been selected for calculation, PROSPER may not
be able to correctly export the VLP file. Pay particular attention to GLR and
GORs.
Unconstrained System
Calculate  Unconstrained System (IPR + VLP) is used to calculate the Pressure and
Temperature at a downstream node for a range of specified rates.
Â
The input is:
•
•
•
Water cut
Time since start of production
Rate values for calculation
The output is:
•
•
•
Well head temperature
Sand-face pressure.
Well head pressures
The IPR input in the System menu is used to determine the flowing bottom hole pressure.
An example Unconstrained System input screen is shown below:
Figure 10-48
Unconstrained System
Input
Click OK to display the sensitivity variables input screen. Select suitable VLP and surface
equipment correlations, enter the water cut, the time since production started and a range
of production rates or use the Inflow from the input section to determine rates. Click OK to
display the calculation screen. Click Calculate to start the calculations.
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Figure 10-49
Unconstrained
System
Calculation
Screen
When calculation finishes, the results can be plotted by clicking the Plot button:
Figure 10-50
Unconstrained
System Plot
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10.3.4
Unconstrained VLP (tubing curves)
Select Calculation  Unconstrained VLP (tubing curves) to calculate the downstream node
Pressure and Temperature for specified rates and upstream pressures and a given
temperature.
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The input is:
•
•
•
•
•
Water cut
Time since start of production
Rate values for calculation
Well bottom-hole pressure (First node for this calculation)
Well fluid inlet temperature
The output is:
•
•
Well head temperature
Well head pressures
As the rates and pressures are directly entered, the IPR does not enter into the calculation.
An example Unconstrained VLP screen is shown below:
Figure 10-51
Unconstrained VLP Input
Enter the known pressure and temperature at the first node (usually the sand face), select
correlations for surface equipment and VLP, the calculation nodes and a table of rates.
Note that calculating temperature from top to bottom has no meaning for the Enthalpy
Balance model. Click OK to enter your sensitivity variables and OK again to display the
calculation screen. The pressure at first node can be varied as a sensitivity variable.
Click Calculate to begin calculating the downstream pressure and temperature.
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Figure 10-52
Unconstrained
VLP Calculation
Screen
The results can be plotted by clicking the Plot button:
Figure 10-53
Unconstrained
VLP Plot
As the surface pressures and temperatures are calculated by PROSPER, the lift curves
cannot be readily ordered by top node pressure as required for simulators. A data Export
facility has therefore not been included for this option.
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10.3.5
Unconstrained Gradient
Select Calculation  Unconstrained Gradient (traverse) to calculate pressure and
temperature profiles versus depth for a specified rate.
Â
The input is:
•
•
•
•
•
Water cut
Fluid entry pressure
Fluid entry temperature
Time since start of production
Rate value for calculation
The output is:
•
Pressure and temperature profile along the flow path.
The rate is directly input, and the IPR is not used in the calculations. The solution must
commence from a known upstream temperature. First node pressure and temperature
plus the sensitivity variables are input as for an Unconstrained VLP calculation. An
example of Unconstrained Gradient (traverse) input screen is shown below:
Figure 10-54
Unconstrained Gradient
Input
Click OK to access the sensitivity variables input screen. Enter your sensitivity variables,
then click OK to display the gradient calculation screen. Click Calculate to calculate
pressure and temperature traverses for all combinations of sensitivity variables. An
example gradient calculation screen is shown below:
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Figure 10-55
Unconstrained
Gradient Results
The calculated heat transfer coefficients, average annulus temperature and casing inside
temperatures can be inspected by scrolling to the right in the results screen. Click Plot to
display a plot of temperature and pressure versus depth similar to that shown below:
Figure 10-56
Unconstrained
Plot
Gradient
If time since production started has been selected as a sensitivity variable, this plot can be
used to determine how long a well will take to reach a specified well head temperature.
The effect of insulation on high heat loss sections such as risers can also be readily
investigated. Click Variables  Extended to access a wide range of computed results. The
plot of heat transfer coefficient Vs depth as shown below can be useful in understanding
heat flow in a well:
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Figure 10-57
Heat Transfer Coefficient
Plot
Note the high values of heat transfer coefficient in the casing and riser. Note that in this
example, the heat flow from the casing is small since the temperature difference between
the fluid and formation is minimal.
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The Heat Transfer Coefficient values plotted and listed are referred to the inside
diameter of the pipe containing the flowing fluid.
10.3.6
Match Parameters
For the Enthalpy Balance temperature model, Calculation | Match parameters is used only
to display the correlation parameters that have been previously determined in the Pressure
Only or Rough Approximation matching procedure. To use the multiphase flow correlation
match parameters from a predicting pressure only case, you can simply enter the
parameters by hand, or pick them up from the output file of a relevant Pressure Only case.
The match parameters can be applied to an Enthalpy Balance case by carrying out the
following steps:
•
Open the *.OUT file for a Pressure Only case that contains the required matched
correlations.
•
Open the *.SIN file for your pressure and temperature prediction application
•
Perform the pressure and temperature analysis
•
Save a .OUT file for the pressure and temperature prediction application. This file
will now contain the matched correlations.
PETROLEUM EXPERTS LTD
11 Design Menu
The Design Menu is to enable the user to perform various artificial lift designs. The user can
access gas lift, ESP, HSP, PCP’s and Gas Lift with Coil Tubing design program modules.
The design menu is active only if an artificial lift method has been selected in the
main Options screen.
The design option will correspond to the artificial lift method selection in the main
Option screen.
Artificial lift design is not enabled when the Enthalpy Balance temperature model
is in use.
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Before the user can proceed ahead with artificial lift design, PVT, down hole equipment and
IPR information must be input.
If artificial lift equipment details have been entered in the System section, they
will be overwritten or ignored by the design process.
Once a design has been prepared using the Design section, the Calculation
module enables the user to compute sensitivities for new or existing artificial lift
systems.
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11.1 GAS LIFT DESIGN
The gas lift design can be used to optimise the design of gas lifted wells.
The program will determine the spacing of unloading valves and calculate the
valve test rack setting pressures.
Designs can also be performed for existing wells having mandrels installed at
fixed depths.
Design performance can be evaluated using the Gas Lift QuickLook or
calculating system sensitivities. (Refer to Chapter 9)
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Menu Options
If gas lift was selected as a lift method in the Options menu the following additional options
will be available in the Design-> Gaslift menu:
•
•
•
New Well
Existing Mandrels
Gas Lift Adjustments
The gas lift design section of the program can be used to determine the optimum gas lift
equipment for a given well. PROSPER calculates the maximum production rate possible, the
corresponding optimum gas lift rate, the valve spacing to unload the well and the test rack
setting pressure for each valve.
Designs can also be prepared for wells having mandrels already set at fixed depths.
2 -57
CHAPTER 11 – DESIGN MENU
For gas lifted wells, the flowing well temperatures can be either entered by the user
(Predicting Pressure only), or estimated using the Rough Approximation (Predicting
Pressure and Temperature).
Gas Lift Valve Database
This is a database in which gas lift valve data is stored. The valve manufacturer, type,
specification, port size and R-value can be entered. These valves can then be selected to
be included in the gas lift design of a well. The program will determine the dome pressure
and test rack setting pressure of the selected valves. The database must be loaded with
appropriate valve data prior to carrying out a design.
ESP DESIGN
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The ESP design section calculates the pump duty required to achieve a given
design rate and allows the user to select a suitable combination of pump, motor
and cable from a user entered database of equipment performance
characteristics.
Design performance can be evaluated using the ESP QuickLook or calculating
system sensitivities. (Refer to Chapter 9)
Menu Options
If electric submersible pump was selected as a lift method in the Options menu the following
additional options will be available in the Design -> Electrical Submersible Pump menu:
•
•
•
•
Design
Pump Database
Motor Database
Cable Database
The ESP design section calculates the head requirement, pump intake and discharge
pressures required to achieve a specified surface production rate. The program then allows
the user to select a combination of pump, motor and cable that is suitable for the service.
The design operating point can be plotted on the pump performance curve.
Databases
This section allows the input and maintenance of manufacturer's performance curves for
pumps, motors and cables. The design section selects ESP components from those
previously entered in the database. Note that pump, motor and cable data must be entered
in the database before an ESP design can be done.
HSP DESIGN
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The HSP design section calculates the pump duty required to achieve a given
total (produced + power fluid) rate and allows the user to select a suitable
combination of pump and turbine from a user-entered database of equipment
performance characteristics.
Design performance can be evaluated using the HSP QuickLook or calculating
system sensitivities. (Refer to Chapter 9)
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Menu Options
If hydraulic drive down hole pump was selected as a lift method in the Options menu the
following additional options will be available in the Design-> Hydraulic Pump menu:
•
•
•
Design
Pump Database
Turbine Database
The HSP design section calculates the head requirement, pump intake and discharge
pressures required to achieve a specified surface total production (produced fluid + power
fluid) rate. The program then allows the user to select a combination of pump and turbine
that is suitable for the service. The design operating point can be plotted on the pump
performance curve.
Databases
This section allows the input and maintenance of manufacturer's performance curves for
pumps and turbines. The design section selects HSP components from those previously
entered in the database. Note that pump and turbine data must be entered in the database
before an HSP design can be done.
PCP DESIGN
The PCP design section calculates the pump duty required to achieve a given
total (produced + power fluid) rate and allows the user to select a suitable
combination of pump and rods from a user-entered database of equipment
performance characteristics.
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Menu Options
If Progressive Cavity Pump was selected as a lift method in the Options menu the following
additional options will be available in the Design-> Progressive Cavity Pump:
•
•
•
Design
Pump Database
Rods Database
The PCP design section calculates the head requirement, pump intake and discharge
pressures required to achieve a specified surface total production. The program then allows
the user to select a combination of pump, and rods that is suitable for the service.
Databases
This section allows the input and maintenance of manufacturer's performance curves for
pumps and Rods.
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CHAPTER 11 – DESIGN MENU
11.2 Gas Lift Design
11.2.1
New Well
Selecting Gas Lift Design | New well from the Design menu will display the following input
screen. This is the screen, where the artificial lift design problem is set up. The gas lift input
data screen is divided into several areas. The Input parameters panel is used to enter the
design operating conditions. The other panels allow the user to enter the design options for
a given application.
Figure 11-1
Gas Lift Design (new well)
11.2.1.1
Setting Up the Design Problem
Setting the artificial lift design problems is defining the various parameters in Figure 11-1.
These are described below:
Design Rate Method
•
User entered
Use this option when the design production rate and gas lift gas injection rate is already
known or when modelling the performance of an existing installation. If a maximum
production calculation has been previously done, the lift gas and design production rates
can be User Entered. The design rate can be entered either in terms of liquid or oil
production only. The design lift gas injection is entered as the Maximum gas available.
•
Maximum production
PROSPER will find the maximum possible oil production rate by determining both the
optimum gas injection rate and depth. This is achieved by calculating the oil production
for a given GLR injected and increasing the GLR until the optimum is found.
•
Maximum revenue
Using user-entered economic parameters for oil and sales gas revenue, produced water
processing and lift gas cost, the program will find the gas lift design that maximises total
revenue (oil and gas revenue less water and injection gas processing costs). The same
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5 - 57
search procedure as for Maximum production is carried out using the cost function in
place of the oil production rate.
both Maximum production and Maximum revenue design methods, a maximum
 For
liquid rate is required to be input. This allows the user to honour production
constraints imposed by surface facilities or off take targets.
Valve Type
•
Casing sensitive valves
o
•
Tubing sensitive valves
o
•
Enter the minimum casing pressure drop to close valves.
Enter the percentage difference in Pcasing - Pwh to close valves.
Proportional response valves
o
PROSPER determines the closing pressure as part of the design calculations.
Valve Settings (Casing pressure operated valves only)
For casing pressure operated valves, there are 3 options for setting valve dome pressures:
•
Pvc = Gas Pressure
PROSPER in this case sets valve dome pressures to balance the casing pressure at
depth. Unloading valves will close when the casing pressure drops below this value.
A small value of Casing Pressure to Close Valves will ensure that the unloading
valves will remain shut.
This design method ensures maximum injection depth and hence maximises
production rates.
•
Â
•
•
All Valves Pvo = Gas Pressure
Dome pressures are set so that valves open with the design casing pressure at
depth. The casing pressure must be reduced by at least R(Pvo - Pt) to close valves
for this option. PROSPER designs using the maximum of dP to close valves or the
calculated closing pressure drop. This method reduces the available injection
pressure and will result in lower production rates.
This is the recommended design setting when designing new wells.
First Valve Pvo = Gas Pressure
The first valve dome pressure is set to open on the design casing pressure at depth.
Subsequent valves are set to close on design casing pressure. This method gives
additional safety for the opening of the first unloading valve without sacrificing available
pressure for the deeper unloading valves.
Pmin - Pmax
Enter fraction of TEF
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Injection Point
Before the gas lift design is performed, the user can decide if the operating valve is a gas lift
valve or an orifice.
Dome Pressure Correction above 1200 psi
There are two equations for dome pressure temperature correction for dome pressures
above 1200 psi.
•
No
PROSPER will use the standard API temperature correction method for all pressures.
This method is known to be inaccurate at high pressures. The option is provided for
convenience in comparing results from hand calculations etc.
•
Yes
The API method is used below 1200 psi, and an improved algorithm is used above
1200 psi. This is the default and recommended option.
Check Rate Conformance with IPR
When selected, PROSPER will re-calculate the system solution rate at each step in the
design process to ensure that the design rate can be met. This prevents for example, a
design being done for an unrealistic Enter by User rate.
Â
For speed in comparing designs, this option can be set to No. However, the user
must be aware that the design rate may not be able to be met by the well.
Vertical Lift Correlation
Select the most appropriate correlation for your application. Matched VLP correlations
should be used when available.
Surface Pipe Correlation
Select the most appropriate correlation for your application. Surface pipes (when entered in
surface equipment) form part of the gas lift system in PROSPER and are accounted for when
calculating unloading pressures and flowing pressure losses. This can be important for subsea systems where the flow line head can be significant.
Using IPR for Unloading
•
Yes
This is the recommended PROSPER unloading valve trim sizing method. Unloading
valves are sized to achieve a minimum flowing gradient above the valve assuming
that the load fluid is being produced. The IPR is used to calculate the well production
rates during unloading. Minimum transfer dP (as explained under inputs below and
Figure 11-2) is ignored for this option.
•
No
This is the standard hand-calculation method. Unloading valve trims are sized to
achieve the GLR required to lower the tubing pressure to the transfer pressure. The
GLR is based on the full design production rate - the actual production rate during
unloading is not calculated. This results in the selection of larger valve trims.
Minimum transfer dP is used to increase the transfer pressure, thereby reducing the
unloading gas requirement and valve trim size.
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Orifice Sizing On
Two options are available:
• Calculated dP at Orifice
• Min dP Across Orifice
Input Parameters
Having set up the calculation options, enter values for the following variables on the Input
Parameters panel:
Maximum gas available
• Set to the maximum gas available at normal operating pressure for maximum
rate or revenue methods.
•
For Entered by User designs, set to the actual injection for the design
production rate.
Maximum gas during unloading
• Enter the maximum gas available at the unloading pressure for unloading the
shallowest valve.
Flowing top node pressure
• If surface equipment has been entered, this is the manifold pressure
• Otherwise, enter the flowing wellhead pressure.
Unloading top node pressure
• Enter a lower unloading pressure if e.g. the separator is bypassed during
unloading
• Otherwise leave set the same as flowing top node pressure.
Operating injection pressure
• Available gas injection system pressure available at the casing head. This is
not the final operating injection pressure.
• If the Safety equipment option has been selected, pressure losses along
surface pipes are computed also.
Kick off injection pressure
• Leave set to normal injection system pressure unless an auxiliary source of
high pressure kicks off gas is available.
• This pressure is used to space the first unloading valve. If a sufficiently high
pressure is entered, then no unloading valves will be needed.
Desired dP across valve
• User selected design pressure loss across valve orifice to ensure well and
gas injection system pressure stability. Usually in the order of 100-200 psi.
Maximum Depth of Injection
• Constrains the maximum injection depth to be shallower than the production
packer.
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Water cut
•
Design producing water cut.
Minimum Spacing
• Sets the minimum spacing between valves. Use 200 - 400 ft normally.
Static gradient of load fluid
•
Density of fluid to be balanced by casing pressure during unloading.
Minimum transfer dP
• Only active when Ignoring IPR for Unloading has been selected. If set to
zero, unloading valve trims will be sized to inject sufficient gas to lower the
unloading tubing pressure to the transfer pressure at the valve depth.
• Increasing the value of Minimum transfer dP will lower the unloading GLR
injected and reduce trim sizes.
Referring to the sketch (Figure 11.2) below, the transfer pressure is:
(Pmin) = Ppd - (Ppd - Pid) * % minimum transfer dP /100
Increasing the injection GLR shifts the tubing gradient during unloading closer to the
objective gradient line (i.e. to the left). The unloading valve trim is sized for the GLR
corresponding to the required transfer pressure. Values of 5 to 25% are commonly
used.
Figure 11-2
Minimum Transfer dP
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Maximum port size
• Depends on valve series selected. PROSPER will select multiple orifice valves
for high gas injection rates if the design injection cannot be passed by one
valve of Maximum port size.
Safety For Closure Of Last Unloading Valve
• Extra dP to ensure that the last unloading valve before the orifice is closed
11.2.1.2
Gas Lift Valve Selection
Once the design problem has been set, the next stage is to tell PROSPER the kind of valves
that will be picked up from data base for design.
Click the Valves button to select the type of valves you want to use in the design from an
internal database.
Â
Refer to Section 11.1.4 for how to enter valve data or import it from an external
source.
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11.2.1.3
Performing the Design (New Well)
Once the input data has been defined and the valves type selected, click Continue to access
the Gas Lift design screen. The following example is for casing sensitive valves:
Figure 11-3
Gas Lift Design (new well)
Calculation
Â
A screen similar to that above will be displayed if design for Maximum Rate or
Maximum Revenue has been selected.
Displaying the Well Performance Curves / Finding Design Rate (New Well)
The first step is to find the design production rate.
• Click Get Rate. PROSPER will determine the optimum Gas Lift injection rate
and maximum oil production rate.
• If the design rate is Entered by User, the upper (Rate calculation) part of the
screen is not displayed.
Â
The Get Rate process calculates oil production as a function of gas injected.
When the calculations have finished, the results can be displayed in the form of a well
performance curve by clicking Plot. A graph similar to the following will appear:
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Figure 11-4
Well
Performance
Curve
The target design rate and GLR injected can be read off the performance curve plot. The
design rate is:
•
•
•
Â
The maximum oil production shown in the Performance curve plot, provided that the
available gas injection and liquid production rate limits have not been exceeded.
In case the maximum gas available is exceeded by the highest oil rate on the plot,
the oil rate corresponding to maximum available gas is taken as design rate.
PROSPER will design for the maximum oil production rate entered in the main input
screen, if it exceeds the rate calculated from the performance curve.
The performance curves can span several flow regimes. Discontinuities in
some flow correlations may cause occasional curve fitting problems. In such
cases, a correlation such as Hagedorn Brown may give better results.
Calculating Valve Spacing
To perform the valve spacing, click Design.
•
•
•
•
The program will then determine the depth of the operating valve and the spacing for
the unloading valves. Depending on the design settings, this will usually take more
than one pass.
On the first pass, the injection and unloading valve depths are determined assuming
no casing pressure drop to close valves.
Having determined the number of valves to use, the operating valve depth is revised
to reflect the new operating casing pressure.
The spacing procedure is repeated using the revised operating casing pressure until
the number of unloading valves and their setting depths no longer change.
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Â
When Check Rate Conformance with IPR is set to Yes, PROSPER recalculates the solution rate and reduces the design rate if necessary. The final
design production and Gas Lift injection rates are displayed on the design
gradient plot.
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Calculating the Valve Test Rack Setting Pressures
To display the valve details click Results and the following screen will be displayed:
Figure 11-6
Valve Design
Results
Â
•
Â
The valve depths, tubing pressure, unloading gas injection rate and trim sizes
are shown in the left screen panel.
To calculate the dome pressures, click Calculate on this screen and PROSPER will
compute the valve test rack setting pressures at 60°F.
Valve types are identified as Valve for unloading valves, or Orifice for the
operating valve. No opening or dome pressure calculations are made for the
orifice.
The design parameters such as valve depth, opening and closing pressures, orifice size etc.
are displayed in a table. Use the scroll thumb below the table to scroll right to see items e.g.
R-value, not visible in the display window.
Â
Once a design has been completed, its performance should be checked over the
range of expected well conditions. Transfer the gas lift design and valve setting
details into Equipment  Gas Lift, then use Calculation  System to compute
sensitivities. Alternatively, Matching  Quicklook can be used to evaluate a
design.
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11.2.2
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Existing Mandrels Design
This option enables the user to design gas lifted artificial lift systems for existing
installations.
To perform the fixed mandrel depth design, click Design  Gas lift design | Existing
mandrels. The following input screen will be displayed:
Figure 11-7
Fixed Mandrel Depth
Design
This screen is similar to the Gas lift design (New well) screen, except that the variables
relating to spacing the valves have been removed.
11.2.2.1
Setting Up the Design Problem
Setting the artificial lift design problems is defining the various fields in Figure 11-8.
These are described below:
Design Rate Method
Three methods are available:
•
•
•
Entered By User
Calculated From Max Production
Calculated From Max Revenue
Â
The Design Rate methods are similar to those of a New Well Design
Valve Type
•
Casing sensitive valves
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CHAPTER 11 – DESIGN MENU
o
•
Enter the minimum casing pressure drop to close valves.
Tubing sensitive valves
o
•
15 - 57
Enter the percentage difference in Pcasing - Pwh to close valves.
Proportional response valves
o
PROSPER determines the closing pressure as part of the design calculations.
Valve Settings (Casing pressure operated valves only)
Four options are available:
•
PVc = Gas Pressure
•
First Valve PVo = Gas Pressure
•
All Valves PVo = Gas Pressure
•
Pmin - Pmax
Enter fraction of TEF
Â
These Valve Settings are similar to those of a New Well Design
Injection Point
Before the gas lift design is performed, the user can decide if the operating valve is a gas lift
valve or an orifice.
Dome Pressure Correction Above 1200psig
There are two equations for dome pressure temperature correction for dome pressures
above 1200 psi.
•
No
•
Yes
Â
The Design Correction methods are similar to those of a New Well Design
First Valve Choice
• Completion Fluid to Surface
Unloading valves will be placed assuming that completion fluid fills up the entire well
and thus must be unloaded from the entire well.
Â
This is the most conservative unloading requirement and is the default option.
• Completion Fluid Level Calculated
PROSPER estimates the standing liquid level from the reservoir pressure and static
pressure gradient. Any mandrels that are above this depth will be set with “Dummy
valves”.
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Â
This approach can save valves for low pressure reservoirs. The user must be
certain that work over fluids can leak off to balance the reservoir pressure
• Minimum Squeeze PI Method
This method can be used when the well productivity is sufficient to ensure that
completion fluids can be squeezed into the formation during unloading. An unloading
tubing gradient is calculated by taking the static reservoir pressure and increasing the
injected GLR, until the gradient arrives at the design top node pressure. Unloading
valves are spaced by comparing this tubing gradient with the available casing pressure
at depth.
•
Minimum Squeeze PI Method (ELF)
An unloading tubing gradient is calculated by taking the static reservoir pressure and
increasing the injected GLR until the gradient arrives at the design top node pressure.
Unloading valves are spaced by comparing this tubing gradient with the available
casing pressure at depth.
Â
This method can be used when the well productivity is sufficient to ensure
that completion fluids can be squeezed into the formation during unloading.
Check Rate Conformance with IPR
• Yes
• No.
Â
Similar to that of a New Well Design
Use IPR For Unloading
• Yes
• No
Â
Similar to that of a New Well Design
Orifice Sizing On
Two options are available
• Calculated dP at Orifice
• Min dP Across Orifice
Vertical Lift Correlation
• Select the most appropriate correlation for your application.
Surface pipe correlation
• Select the most appropriate correlation for your application. This is required
now that surface pipes (when entered) form part of the gas lift system in
PROSPER.
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Input Parameters
The input parameters required by an Existing mandrel Design are similar to those for a new
well. The parameters required are:
•
•
•
•
•
•
•
•
•
•
•
•
Â
Maximum gas available
Maximum gas available during unloading
Flowing top node pressure
Unloading top node pressure
Operating injection pressure
Kick off injection pressure
Desired dP across valve
Water cut
Static gradient of load fluid
Minimum Transfer dP
Maximum port size
Safety For Closure Of Last Unloading Valve
For a detailed explanation of these input parameters refer to the details for these
given in the New Well Design.
11.2.2.2
Defining the Depths of Existing Mandrels
After setting up the input for the design problems, next, click Mandrels and enter the
measured depths of the existing gas lift mandrels as on the following screen example.
Â
Enter the depth of all mandrels in the well, including those fitted with dummy
valves.
PROSPER will select the best depths for the operating and unloading valves from
this list.
When more mandrels are available than needed for the current design, PROSPER
will automatically set dummies at the intermediate depths.
The valve type initially entered is unimportant.
PROSPER will overwrite the valve type when it performs the design.
This table is effectively a list of the potential valve depths and can be used to prepare
designs for new wells where equipment limitations determine the available mandrel depths.
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Figure 11-8
Fixed Mandrel Depth
Details
Â
If entries are made in the Casing Pressure drop or Max. Gas Injected
fields on the mandrel depth screen shown in Figure 11-9, these values will
overwrite the values entered on the main design screen.
Leave these fields blank to design using the same values of pressure drop or gas
injection for each unloading valve.
Â
The mandrel depths can be picked up from either Matching  QuickLook or
Equipment  Gas Lift using the Transfer button, or entered by hand. The usual
PROSPER editing facilities are available for manipulating the table entries.
11.2.2.3
Gas Lift Valve Selection
Having entered the mandrel depths, select a valve series using the Valves button as for the
Gas lift design (New well) case. This will define the set / type of valves that will be used for
design.
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11.2.2.4
19 - 57
Performing the Design (Existing Mandrels)
Click Continue to access the gas lift design calculation screen.
If a calculated rate design method has been selected, a screen similar to the following will be
displayed:
Figure 11-9
Fixed Mandrel Depth
Design
Displaying the Well Performance Curves / Finding Design Rate (Existing)
Click Get Rate, and the program will determine the optimum gas injection depth and
production rate for the well given the available injection gas rate and pressure limits.
• The design rate calculation begins by selecting a GLR Injected and a low production
rate.
• A pressure traverse is calculated from the THP downwards using the gas lifted GLR
until the casing pressure equals the tubing pressure less the Desired dP across
valves.
• A check is then made to find the next shallowest mandrel. The traverse is calculated
from the next shallowest injection mandrel depth down to the sand face using the
non-Gas Lifted fluid gradient.
• The IPR and VLP pressures are compared.
• The rate is increased and the calculation repeated until an intersection with the IPR
(rate solution) is found.
• The injection GLR is increased until the optimum production rate is found.
• This procedure ensures that the available mandrel depths are honoured at every
calculation step.
Once the calculations have stopped, click Plot to make a plot of the production rate Vs gas
injected. It is similar to that of a new well design.
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Calculating Mandrels with Valves / Displaying their Position
The design is performed for the target rate by clicking Design. Once the calculation has
finished, the design can be checked graphically by clicking the Plot button to display a plot
similar to the following:
Figure 11-10
Gas Lift Design
Plot
The Design proceeds as follows:
• The annulus pressure gradient plot begins at the design casing pressure and
traverses down to the first valve.
• It is then shifted back as the casing pressure is lowered to close the unloading valve.
The annulus traverse is recalculated from surface with the reduced pressure and
continues down to the next valve and so on until the operating valve depth is
reached.
• PROSPER will optionally check the design rate for conformance with the IPR and
reduce the design rate if necessary.
• The design gradient plot shows the Actual design production and Gas Lift injection
rates together with the injection pressure at surface while injecting at the orifice.
Calculating the Valve Test Rack Setting Pressures ( Existing )
To display the valve setting calculations, click Results from the Design screen. Click
Calculate, and PROSPER will determine the dome pressures and test rack setting pressure
for the selected valves as in the following example:
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Figure 11-11
Gas Lift Valve
Calculations
•
To access parameters such as the transfer pressure and port size, click on the scroll
arrow at the bottom of the Input parameters panel. The other entries that are hidden
to the right of the screen will be revealed.
Click Calculate and the dome pressures will be updated for the new valve series.
Â
To perform sensitivity calculations for the current design, the valve depths must
be transferred to Equipment  Gas Lift before making calculations. Based on
flowing tubing pressures PROSPER determines the injection point during
production.
11.2.3
Â
Notes on Gas Lift Design
These are valid both for new wells and wells with existing mandrels.
11.2.3.1
Valve Spacing
Valve spacing is not affected by the choice of unloading method, but the trim size selection
depends on whether the well IPR is used for calculating the unloading rate or not.
The following discussion refers to casing sensitive valves.
•
For the design rate and GLR injected, a pressure traverse is calculated from the top
node (including the flow line, if present) downwards using the gas lifted flowing
gradient.
•
The injection depth is the depth at which the flowing tubing pressure equals the
casing pressure gradient less the design dP loss across the orifice or the Maximum
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Injection Depth (packer depth), whichever is the shallower. This step establishes the
flowing tubing pressure gradient to be used for valve spacing.
•
The shallowest unloading valve is placed at the depth that balances the tubing load
fluid pressure with the casing pressure (less a 50 psi safety margin) at that depth.
•
Further unloading valves are placed by traversing down between the load fluid
pressure gradient and gas lifted tubing pressure gradient (calculated for the design
gas lifted production rate) lines.
•
Valves are placed ever deeper until the inter-valve spacing equals the pre-set
minimum, or the maximum injection depth has been reached.
•
Once the first pass design is complete, PROSPER re-calculates the flowing gradient
tubing using the current operating valve depth. For casing sensitive valves, the valve
depths are re-calculated to allow for the casing pressure drop to close valves. The
process is repeated until the valve depths no longer change.
When Check Rate Conformance with IPR is set to Yes, the solution rate is checked to
ensure that it can be achieved. PROSPER reduces the design rate if necessary and repeats
the spacing exercise.
11.2.3.2
A Note on Designing with Tubing Sensitive Valves
Tubing sensitive valves operate with a constant casing pressure and rely on increasing
tubing pressure as the well unloads to close the unloading valve and transfer injection to
lower valves.
•
To prepare a design for tubing sensitive valves, the required input is the same as for
Casing Sensitive valves except that instead of entering the casing pressure drop to
close valves, the percentage Pcasing - Pwh to close valves is required.
11.2.3.3
Spacing Procedure for Tubing Sensitive Valves
The injection point is found as for casing sensitive valves by finding the intersection of the
minimum tubing gradient line and the casing pressure gradient (less a 50 psi safety margin).
The first unloading valve is spaced as for the casing sensitive case.
Intermediate unloading valves are spaced by traversing down using the load fluid gradient
from the transfer pressure to intersect the casing pressure gradient for the operating
injection pressure. The transfer pressure (tubing pressure at which the unloading valve
closes) is calculated using the value of % Pcasing -Pwh as follows:
•
The surface pressure corresponding to the specified % difference between the operating
tubing and casing pressures is calculated.
•
A straight line is extended from this point to intersect the tubing pressure at the injection
point. The valve transfer pressure is defined at any depth by this line.
•
A small value of % difference results in transfer pressures close to the flowing tubing
gradient. While this results in a design with few unloading valves, any small increase in
flowing tubing pressure may cause unloading valves to re-open.
•
A larger value of % Pcasing -Pwh will increase the transfer pressure further away from
the flowing tubing gradient. This provides a greater safety margin against multi-point
injection, but requires the unloading valves to be spaced more closely.
Selecting transfer pressures using only the % Pcasing - Pwh straight line can result in
shallow valves having a too conservative transfer pressure, and the deeper valves may
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transfer too close to the tubing gradient line. PROSPER adjusts the design transfer
pressures so that valves are spaced efficiently while at the same time ensuring a good
safety margin against multipoint injection.
Figure 11-12
Valve Spacing - Tubing
Sensitive Valves
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Having performed a design, it is recommended that the Matching  Quicklook
and Design  Gas Lift Diagnostic sections be used to check your design and
examine the effect of varying design and producing conditions.
11.2.3.4
A Note on Proportional Valves
Merla proportional valves are a hybrid of tubing- and casing- sensitive characteristics. A
design procedure and valve characteristics for the most common proportional valves is
currently under field testing.
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11.2.4
Gas Lift Valve Database
To perform a Gas Lift design, PROSPER must have appropriate valve data loaded in its
database. To enter and maintain the valve data that PROSPER requires for Gas Lift design,
select Design  Gas Lift Valve database, and a screen similar to the following will be
displayed:
Figure 11-13
Gas Lift Valve Database
Initially, the gas lift valve database will be empty. Use the Add button to add records
(valves). To edit valve details, first select the required valves by clicking the check box to
the left of the entry, or click All to select all records. The program will display a screen
similar to the following for both additions and amendments:
Figure 11-14
Gas Lift Valve Database Amend Record
Click OK to edit the next selected record or return to the database screen. Export and
Import buttons are provided which enable the reading and writing of gas lift valve database
(.GLD) files. These are a convenient way to store or exchange valve characteristics.
PROSPER’s internal working database is contained inside the PROSPER.INI file. A
convenient way to work with large numbers of valve records is to keep them in separate
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.GLD files, and use the database to keep commonly used valves. An example of an ASCII
.GLD file is shown below:
Figure 11-15
.GLD Gas lift valve database
file
valve1
valve1
valve1
valve1
valve1
valve1
valve1
0
0
0
0
0
0
0
R20
R20
R20
R20
R20
R20
R20
monel
monel
monel
monel
monel
monel
monel
8
12
16
20
24
28
32
0.017
0.038
0.066
0.103
0.147
0.200
0.260
A sample valve database (VALVES.GLD) is distributed with PROSPER. It is located together
with the other sample files in the \SAMPLES sub-directory. To load the database, click
Design  Gas Lift Valve Database to display the database input screen. Click Import 
Append and select VALVES.GLD. Click OK to read in the data.
Â
The sample gas lift valve database is provided to allow you to run the examples.
Before designs for field installation, you must first ensure that the database
contains current and accurate valve characteristics.
11.3 Gas Lift Adjustments
The existing Gaslift Design sections allow the user to select and size gas lift equipment for
specified design conditions. Gaslift Adjustments provides additional calculations for testing
gas lift designs under operating conditions. Surface casing pressures when re-starting
production are presented in addition to input parameters needed for setting up automatic
well controllers.
To set up a Gaslift Adjustments calculation, enter the following items:
Figure 11-16
Gas Lift Adjustments
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Design Situation-
Select either New Well or Existing Mandrels.
Valve Type-
Select either Pressure (casing) or Fluid (tubing) operated.
Downstream Pressure Constraint-
Surface pressu 17i10. 40ums
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27 - 57
Figure 11-18
Trasfering valves from
quick look
Figure 11-19
Valves from QuickLook
Once the gaslift equipment details are entered the flowing gradient or static gradient can be
estimated:
Flowing
Calculations are made for flowing conditions at the user-entered target production rate.
PROSPER calculates well performance curves for gas injection at each mandrel depth.
Production rates and pressures at surface and mandrel depth are determined. Annulus
volume and bottoms up times are also calculated. The flowing gradient for the operating
condition can be plotted with opening and closing pressures for each unloading valve
displayed.
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Figure 11-20
Flowing calculations
Figure 11-21
Flowing
calculations
Static
Calculations are made for shut-in conditions. The static tubing gradient is determined using
the liquid density calculated for the producing water cut. When the reservoir pressure
cannot support a full liquid column, a gas gradient is used back to surface.
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Figure 11-22
Flowing
calculations
11.3.1
ESP Design
The Design  ESP Design section allows the user to determine the required pump head to
achieve a specified production rate then to select a suitable combination of pump and motor
for the application. ESP data entered in the System  Electrical Submersible Pumps input
menu is not utilised by the ESP design section. The design results overwrite this section.
Â
Emulsions
If Emulsions have been selected on the Options screen, viscosity corrections are
applied to pump capacity and head. Otherwise, no ESP viscosity corrections will
be applied. If an Emulsion PVT model has been built in the PVT section, then the
emulsion viscosity can be optionally used in the ESP calculations and elsewhere.
As mentioned in the PVT section, emulsion behaviour in oilfield systems analysis
is poorly understood. The emulsion PVT model provides the means to apply
empirical corrections and should be used with caution.
The brief summary of ESP design calculation is as follows:
• The calculations begin at the sand face by calculating the pressure drop from the
sand face up to the pump intake using the standard PVT and tubing size data for the
user-specified production target rate.
• Some ESP installations allow gas to be separated from the oil at the pump inlet.
Consequently, the GOR of the produced oil can be lower above the pump.
• A pressure traverse is then calculated from the known surface pressure using the
modified oil PVT properties above the pump, down to the pump depth.
• The difference between the pump intake pressure and required outlet pressure
together with the design mass flow rate determine the ESP pump duty.
The following description assumes that input of the well details and PVT data have already
been correctly completed and that where applicable, pressure drop correlations have been
matched to field data.
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Designing an ESP installation using PROSPER is divided into two phases. One is where the
head and power requirement calculations are made and the second part is where on basis of
the calculations, the equipment is selected.
11.3.2
ESP Calculate
This section determines the head required to be supplied by the pump to achieve a specified
production rate. Click Design  ESP Design to display the following screen:
Figure 11-23
ESP Design Screen Input
Enter the design liquid rate, water cut, top node pressure and an estimated pump setting
depth in this screen.
Click Calculate to display a blank pump duty calculation screen as shown in Figure11-24.
Click Calculate and the program calculates the pump duty necessary to achieve the design
production rate. PROSPER will display the pump duty solution as follows:
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CHAPTER 11 – DESIGN MENU
31 - 57
Figure 11-24
ESP Pump Duty
Calculation
•
•
•
•
•
Â
PROSPER uses the IPR from System  Inflow Performance to calculate the flowing
pressure at the sand face and the specified VLP correlation to find the pump intake
pressure for the design production rate.
The program then works down from the specified top node pressure to arrive at the
required pump discharge pressure.
The difference between the intake and discharge pressures represents the required
pump head.
PROSPER compresses the liquid and gas as the pressure increases across the
pump, so the volumetric rate will be less at the discharge than at the pump inlet.
The mass flow rate and the required head are used to determine the pump fluid
power requirement.
If an inlet gas separator is to be used, enter the separator efficiency before
carrying out the calculation. The program allows the percentage of free gas set
by the separator efficiency to be produced up the annulus, and the remainder to
be compressed through the pump. Hence, the PVT properties of the well fluids
can be different below and above the pump.
11.3.2.1
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Checking Suitability of Separator Efficiency
To check that the separator efficiency chosen in the input is acceptable for the
design case, the Dunbar Criteria may be used as showed below.
Click Sensitivity to display the intake pressure and intake GLR plotted over a range of gas
separator efficiency curves. Check that the design operating point lies above the empirical
limit represented by the Dunbar Factor line.
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PROSPER MANUAL
32 -57 CHAPTER 11 – DESIGN MENU
Figure 11-25
ESP GLR Sensitivity
11.3.3
ESP (Pump, Motor, Cable) Selection
Having determined the required pump duty, Click OK or press return to return to the ESP
design screen.
Â
•
•
The purpose of this section is to allow the user to select a pump, motor and cable
combination that is capable of meeting the pump duty that has been determined
in the previous step.
Enter reasonable estimates for operating frequency, maximum practical pump O.D.
and length of pump cable.
If required, an additional pump power safety factor and a wear allowance can be
entered.
Click Design and the program will display a pump design screen similar to that shown below:
PETROLEUM EXPERTS LTD
CHAPTER 11 – DESIGN MENU
33 - 57
Figure 11-26
ESP Design Selection
In the Pump drop down box, PROSPER lists the pumps in its database that are capable of
meeting the design requirements.
Pump Selection
PROSPER presents pumps that can meet the following criteria:
•
•
•
•
Â
Inlet rate within range
Discharge rate within range
Head developed at design well rate is near pump's maximum efficiency point
Pump O.D. < user input maximum.
The user must select a pump from those listed.
Motor Selection
Once a pump has been selected
• the pump efficiency is known, so the motor power requirement can now be
calculated.
Proceed to the motor drop down box and select a motor from those listed.
PROSPER lists pumps and motors on the basis of diameter and performance characteristics.
• it is the user's responsibility to ensure that the motor selected is physically compatible
with the pump and that the most economical combination of operating voltage and
current is chosen.
Cable Selection
Once the motor power and voltage option have been determined, a suitable cable must be
selected.
PROSPER displays those cables capable of passing the required current.
• Select a suitable cable from the drop-down box to complete the first pass design.
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PROSPER MANUAL
34 -57 CHAPTER 11 – DESIGN MENU
11.3.3.1
Checking the Pump Design
Click Plot to display the design operating point on the pump performance curve as shown
below:
Figure 11-27
ESP
Plot
Â
•
•
•
•
Design
Normally, the first pass design will have an operating point fairly close to the
selected pump's optimum efficiency. However, as well conditions change with
time, this may not be the best design for the life of the installation
Different combinations of pump and motor can be quickly experimented with in the
ESP design section until an optimum design is obtained.
A report can be generated which gives details of the pump selection and design
conditions.
The robustness of the first pass design must then be checked over the range of
expected well operating conditions by running sensitivities in the Calculation menu
(Refer Section 10.1).
PROSPER allows sensitivities to be run on both well performance and pump
parameters such as pump setting depth and operating frequency.
The ESP system design process is completed by iterating between the Calculation and
Design sections until the final design is optimised over the projected pump run life.
Viscosity corrections, where applicable, will be considered in choice of available pumps and
the number of stages required.
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CHAPTER 11 – DESIGN MENU
35 - 57
11.4 ESP Database
The ESP database is used to store performance curves for pumps, electric motors
and cables.
Â
•
•
To allow users to begin designing ESP systems immediately, PROSPER includes
a basic set of ESP data that has been supplied by the major pump
manufacturers. Due to improvements in pump design etc. the sample data may
not be the latest available. These are in the form of *.DAT file in the”
~/samples/PROSPER “ directory.
Due to improvements in pump design etc. the sample data may not be the latest
available.
For critical design work, the user must first ensure that the database contains
accurate performance data for each pump and motor that may be specified.
11.4.1
•
•
Pump Database
Performance curves are supplied in the form of coefficients for a polynomial equation
fitted to actual performance data.
Click Design  ESP Database Pumps to display an ESP Pumps database screen
similar to the following:
Figure 11-28
ESP Pumps
Database
Scroll through the database entries using the >> and << buttons or click on a pump in the
window at the right hand side of the screen.
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36 -57 CHAPTER 11 – DESIGN MENU
Â
When PROSPER is installed for the first time the database screen will be empty.
The data bases need to be loaded. The data bases can be loaded using the
Import button shown on screen in Figure 11-28.
11.4.1.1
•
•
•
•
Adding a New Pump/Altering an Existing
one/Importing Databases
To add a record (new pump), click Add.
To edit an existing entry, find it using >> and <<, then click on Amend.
Jump between records using the Tab key or the mouse.
When finished data entry, click OK to save the changes.
Data tables can be directly imported from ASCII files using the Import option.
•
•
The required data file structure is given in Appendix E.
The number of stages variable tells the program whether the pump characteristic
polynomial refers to an individual stage, a group of stages (e.g. 100 stages) or a
complete pump assembly.
The contents of the database can be listed to the screen or printer using the Report button.
A plot of pump characteristics can be made using the Plot button.
A typical pump curve is shown below:
Figure 11-29
ESP Pump
Head
Click Variables to select between Head, Horsepower and Efficiency for plotting.
PETROLEUM EXPERTS LTD
CHAPTER 11 – DESIGN MENU
Â
To guard against errors, it is recommended that a plot be made and checked
against published curves whenever new data is entered or alterations are made
to existing entries.
11.4.2
•
•
37 - 57
Motor Database
Motor performance curves are entered via the ESP Database  Motors screen in the
same manner as for pumps.
An example screen is shown below:
Figure 11-30
ESP Motors
Database
•
•
Â
Motor characteristics are entered for each series.
Coefficients are required for Nameplate Amps, RPM, Efficiency and Power factor.
Available horsepower and Power options are entered by clicking the relevant Edit
button.
As plotted, motor speed curves may exceed synchronous speed at low % power
values. This is a characteristic of the polynomial fitting technique used. The
accuracy of motor (and pump) performance curve fits is optimised in the usable
efficiency range.
An example of a motor efficiency plot is shown below:
SEPTEMBER 2003
PROSPER MANUAL
38 -57 CHAPTER 11 – DESIGN MENU
Figure 11-31
Motor Efficiency
Plot
11.4.3
Cable Database
Entry of cable data is via ESP  Database Cables.
Unless you need to add a custom cable size, it should not normally be necessary to modify
the cables database.
An example Cables database entry screen is shown below
Figure 11-32
Cables Database
Entry
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CHAPTER 11 – DESIGN MENU
Â
39 - 57
The ESP databases are stored with .DB extensions in the same directory as the
main PROSPER program files.
Sample ASCII data files (with a .DAT extension) containing pump and motor data
suitable for importing into PROSPER are provided in the \SAMPLES sub directory.
To avoid clutter in the Pumps database, ASCII files of pump characteristics can
be exported.
The ASCII files can be manipulated using a standard editor.
You could then Import only those pumps in common use into the main database.
ASCII .DAT files are the most convenient way to interchange pump coefficients
between users.
Â
Every effort is made to ensure that the sample pump and motor coefficients
supplied with PROSPER are correct. However, it is the User’s responsibility to
ensure they are both accurate and up-to-date. For critical design work, always
refer to your equipment supplier for the latest performance data.
SEPTEMBER 2003
PROSPER MANUAL
40 -57 CHAPTER 11 – DESIGN MENU
11.5 HSP Design
This section allows the user to determine the required pump head to achieve a specified
total production (produced + power fluid) rate then to select a suitable combination of pump
and turbine for the application. HSP data entered in the input menu is not utilised by the
HSP design section.
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Emulsions
If Emulsions have been selected on the Options screen, viscosity corrections are
applied to pump capacity and head. Otherwise, no HSP viscosity corrections will
be applied. If an Emulsion PVT model has been built in the PVT section, then the
emulsion viscosity can be optionally used in the HSP calculations and elsewhere.
As mentioned in the PVT section, emulsion behaviour in oilfield systems analysis
is poorly understood. The emulsion PVT model provides the means to apply
empirical corrections and should be used with caution.
The brief summary of HSP design calculation is as follows:
• The HSP design calculation begins at the sand face by calculating the pressure drop
from the sand face up to the pump intake using the standard PVT and tubing size
data for the user-specified production target rate.
• If the HSP configuration results in commingled fluids the PVT properties of the
combined fluid will be amended for calculations above the pump.
• A pressure traverse is then calculated from the known surface pressure using the
modified oil PVT properties above the pump, down to the pump depth.
• The difference between the pump intake pressure and required outlet pressure
together with the design mass flow rate determine the HSP pump duty.
The following description assumes that input of the well details and PVT data have already
been correctly completed and that where applicable, pressure drop correlations have been
matched to field data.
The design of an HSP installation using PROSPER is divided into two phases. One is where
the head and power requirement calculations are made and the second part is where on
basis of the calculations, the equipment is selected.
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CHAPTER 11 – DESIGN MENU
11.5.1
41 - 57
HSP Calculate
This section determines the head required to be supplied by the pump to achieve a specified
production rate.
Click Design  Hydraulic Pump  Design to display the following screen:
Figure 11-33
HSP Design Screen Input
•
Enter the design liquid rate, water cut, top node pressure, % Power fluid of Reservoir
Fluid and an estimated pump setting depth in this screen.
Click Calculate to display a blank pump duty calculation screen. Click Calculate and the
program calculates the pump duty necessary to achieve the design production rate.
PROSPER will display the pump duty solution as follows:
SEPTEMBER 2003
PROSPER MANUAL
42 -57 CHAPTER 11 – DESIGN MENU
Figure 11-34
HSP Pump Duty
Calculation
•
•
•
•
•
PROSPER uses the IPR from System  Inflow Performance to calculate the flowing
pressure at the sand face and the specified VLP correlation to find the pump intake
pressure for the design production rate.
The program then works down from the specified top node pressure to arrive at the
required pump discharge pressure.
The difference between the intake and discharge pressures represents the required
pump head.
PROSPER compresses the liquid and gas as the pressure increases across the
pump, so the volumetric rate will be less at the discharge than at the pump inlet.
The mass flow rate and the required head are used to determine the pump fluid
power requirement.
For certain configurations the produced and power fluids can be commingled above the
pump. Hence, the PVT properties of the well fluids can be different below and above the
pump.
11.5.1.1
Â
•
•
•
HSP (Pump, Turbine) Selection
The purpose of this section is allow the user to select a pump and turbine
combination that is capable of meeting the pump duty that has been determined
in the previous step.
Enter reasonable estimates for pump speed and maximum practical pump and
turbine O.D.s.
If required, an additional pump power safety factor and a wear allowance can be
entered.
Click Design and the program will display a pump design screen similar to that shown
below:
PETROLEUM EXPERTS LTD
CHAPTER 11 – DESIGN MENU
43 - 57
Figure 11-35
HSP Design
Selection
Pump Selection
In the Pump drop down box, PROSPER lists the pumps in its database that are capable of
meeting the design requirements.
PROSPER presents pumps that can meet the following criteria:
•
•
•
•
Â
Pump Speed within range
Discharge rate within range
Head developed at design well rate is near pump's maximum efficiency point
Pump and O.D. < user input maximum
The user must select a pump from those listed.
Turbine Selection
Once a pump has been selected
• the pump efficiency is known, so the turbine power requirement can now be
calculated.
• Proceed to the turbine drop down box and select a turbine from those listed.
• PROSPER lists pumps and turbines on the basis of diameter and performance
characteristics.
Â
It is the user's responsibility to ensure that the turbine selected is physically
compatible with the pump.
11.5.1.2
Checking the Pump/Turbine Design
Click Plot to display the design operating point on the pump performance curve as shown
below:
SEPTEMBER 2003
PROSPER MANUAL
44 -57 CHAPTER 11 – DESIGN MENU
Figure 11-36
HSP Design Plot
•
•
•
Normally, the first pass design will have an operating point fairly close to the selected
pump's optimum efficiency. However, as well conditions change with time, this may
not be the best design for the life of the installation.
Different combinations of pump and turbine can be quickly experimented with in the
HSP design section until an optimum design is obtained.
A report can be generated which gives details of the pump selection and design
conditions.
The robustness of the first pass design must then be checked over the range of expected
well operating conditions by running sensitivities in the Calculation menu (Refer Section
10.1). PROSPER allows sensitivities to be run on both well performance and pump
parameters such as pump setting depth and pump speed.
The HSP system design process is completed by iterating between the Calculation and
Design sections, until the final design is optimised over the projected pump run life.
Viscosity corrections, where applicable, will be considered in choice of available pumps and
the number of stages required.
PETROLEUM EXPERTS LTD
CHAPTER 11 – DESIGN MENU
45 - 57
11.6 HSP Database
The HSP database is used to store performance curves for pumps and turbines.
Â
•
•
To allow users to begin designing HSP systems immediately, PROSPER includes
a basic set of HSP data that has been supplied by the major pump
manufacturers. Due to improvements in pump design etc. the sample data may
not be the latest available. These are in the form of *.DAT file in the”
~/samples/PROSPER “ directory.
Due to improvements in pump design etc. the sample data may not be the latest
available.
For critical design work, the user must first ensure that the database contains
accurate performance data for each pump and motor that may be specified.
11.6.1
•
•
HSP Pump Database
Performance curves are supplied in the form of coefficients for a polynomial equation
fitted to actual performance data.
Click Design  HSP Database | Pumps to display an HSP Pumps database screen
similar to the following:
Figure 11-37
HSP Pumps
Database
Scroll through the database entries using the >> and << buttons or click on a pump in the
window at the right hand side of the screen.
Â
When PROSPER is installed for the first time the database screen will be empty.
The databases need to be loaded. The databases can be loaded using the
Import button shown on screen in Figure 11-37
SEPTEMBER 2003
PROSPER MANUAL
CHAPTER 11 – DESIGN MENU
11.6.2
47 - 57
Turbine Database
Turbine performance curves are entered via the Hydraulic Pump  Turbine Database screen
in the same manner as for pumps. An example screen is shown below:
Figure 11-39
HSP Turbines
Database
Motor characteristics are entered for each turbine settings. Coefficients are required for
Head and Power. These are entered (or can be fitted) by clicking the Edit button.
An example of a turbine head generated plot is shown below:
SEPTEMBER 2003
PROSPER MANUAL
48 -57 CHAPTER 11 – DESIGN MENU
Figure 11-40
Turbine Head
Generated
Plot
Â
Every effort is made to ensure that the sample pump and motor coefficients
supplied with PROSPER are correct. However, it is the User’s responsibility to
ensure they are both accurate and up-to-date. For critical design work, always
refer to your equipment supplier for the latest performance data.
Turbine performance curves are entered via the Hydraulic Pump  Turbine Database screen
in the same manner as for pumps.
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CHAPTER 11 – DESIGN MENU
49 - 57
11.7 Progressive Cavity Pump Design
Figure 11-41
Well
configuration
The stator is made out of elastomer encased into the steel pipe and this is attached to the
tubing string.
In order to create a lifting pressure, there must be a differential pressure between the
cavities, therefore a tight seal between rotator and stator is required; however there will be
always slippage of the production fluid due to:
Differential pressure
Number of stages
Fluid properties
Temperature and type of material
Applications:
The pump can lift up to 1500 bpd or more and handle extremely viscous crudes efficiently as
well as solid particles. The PCP will be able to reduce by 50 or 60 % on some cases the
power consumption. Based on some operational test results, the pump can perform well in
temperatures around 150 degrees due to limitations in the elastomer, which constitutes the
internal lining of the stator and generally it is considered the weakest point of the PCP.
11.7.1
Setting Up the Pump Database in PROSPER
In Prosper before you perform any calculation considering the progressing cavity pump the
user have to build the Pump database according to the data provided by the manufacturer.
From Prosper system summary in the artificial lift section the user can select
Progressive Cavity Pump
Sucker rod drive or downhole drive
Before you perform the design from the main screen you select Design/ Database
SEPTEMBER 2003
PROSPER MANUAL
50 -57 CHAPTER 11 – DESIGN MENU
Figure 11-42
Pump data
Base
In this section select PCP/ Pumps.
Then press the button Add. You have to enter the correspondent data as indicated below
according to the particular pump that you want to use.
11.7.2
Database
The Calculation menu provides you with the relevant calculation options. Calculations to
determine pressure and temperature profiles, perform sensitivity analyses, make gradient
comparisons and generate lift curve tables are available from this menu.
Figure 11-43
Pump data Base
Input Data
Usually each manufacturer provides the main characteristics of the pump, including:
Flow rate
Head rating
Reference speed (i.e. rpm at zero head)
Specific outside diameter of the rotor
The user should enter the correspondent specifications for each pump.
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CHAPTER 11 – DESIGN MENU
11.7.3
51 - 57
Typical Pump Curves
For example, considering the following pump curves
PERFORMANCE CHART
PUMP A 3-1400
Figure 11-44
Performance
data
50
1600
45
1400
40
1200
35
BFPD
1000
30
Shaft HP
800
600
15
Shaft HP
400
10
Shaft HP
200
5
Shaft HP
Shaft HP
0
0
100
25
20
Shaft HP
200
300
400
500
0
600
RPM
Manufacturer
Pump Series
Pump Model
Pump size
Maximum Head
Reference speed
Reference rate
Pump Volume
Pump length
Sator pitch
Rotor I.D.
Rotor element
SEPTEMBER 2003
:
:
:
:
:
:
:
:
:
:
:
:
Pump A
2.89
1200
4.5
3900
500
1200
18
16
9
1.38
2
in
ft
rpm
STB/day
in3
ft
in
in
PROSPER MANUAL
52 -57 CHAPTER 11 – DESIGN MENU
Figure 11-45
Input data
From the performance chart data the correspondent hydraulic head is 3900 with a maximum
rate of 1200 bpd and required speed 500 rpm. From the same chart, the maximum shaft
power at 500 rpm is 50 HP.
Figure 11-46
Performance
Pump Plot
To be able to perform a complete nodal analysis considering the PCP the correspondent
data for a given rod needs to be entered.
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CHAPTER 11 – DESIGN MENU
53 - 57
From the main menu select Design/ Database/ Sucker Rods
Figure 11-47
Sucker Rods
select Amend and enter the correspondent data of the rods
Figure 11-48
Sucker Rod
Input data
You can repeat the same procedure for different types of pumps and rods until you build a
particular pump and rods data base.
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PROSPER MANUAL
54 -57 CHAPTER 11 – DESIGN MENU
11.8 Coil Tubing Design
The following 5 lift method options are available when Oil is selected as a fluid type.
•
Naturally Flowing
No artificial lift.
•
Gas Lifted
Three different approaches are provided. Annular gas lift is handled by PROSPER.
If the Flow Type is Annular Flow and a Gas Lift method is selected, then
PROSPER automatically switches to model gas injection down the tubing, and
production up the annulus.
•
Electric Submersible Pump
An ESP installation can be analysed or designed using this option.
•
Hydraulic Drive Downhole Pump
An HSP installation can be analysed or designed using this option.
•
Progressing Cavity Pump
A PCP installation can be analysed when this option is used
•
Gas Lift with coil tubing
Figure 11-49
Coil Tubing option
Select Design /Coil Tubing with Gas Lift
When you select this option there are two different ways to consider the design. The user
can specify the injection depth or the optimum injection depth.
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CHAPTER 11 – DESIGN MENU
55 - 57
For this particular example the idea is to reduce the area exposed to flow in order to
increase the velocities, then you can use fixed depth of injection.
It has been decided to use a 1 ¼ in CT to 7850 ft
Figure 11-50
Coil tubing
input data
Figure 11-51
Coil Tubing
Design
After calculating, select done and design. From this panel you will be able to select
the pump and rods; the more pumps you have in your data base, the wider is the
range of design choices available.
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56 -57 CHAPTER 11 – DESIGN MENU
Figure 11-52
CT – Gas Lift
Design
From the screen, after calculations are performed, the maximum injection depth is 6380 ft
And the correspondent liquid rate 200 bpd.
Figure 11-53
PCP results
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CHAPTER 11 – DESIGN MENU
57 - 57
Coil Tubing Data
Out side
diameter
inch
Wall
Thickness
inch
Inside
Diameter
inch
Body Yield Load
lb
Internal
Yield
Pressure
psi
1
1
1.25
1.25
1.25
1.25
1.5
1.5
1.5
1.75
1.75
1.75
2
2
2
2.375
2.375
2.375
2.875
2.875
2.875
3.5
3.5
3.5
0.08
0.109
0.08
0.109
0.125
0.156
0.095
0.125
0.175
0.109
0.134
0.188
0.109
0.134
0.203
0.109
0.134
0.203
0.125
0.175
0.203
0.134
0.175
0.203
0.84
0.782
1.09
1.032
1
0.938
1.31
1.25
1.15
1.532
1.482
1.374
1.782
1.732
1.549
2.157
2.107
1.969
2.625
2.525
2.469
0.134
3.15
3.094
18500
24420
23520
31260
35340
42890
33550
43200
58280
44950
54420
73800
51800
62840
91680
62080
75470
110810
86390
118750
136320
113360
146.24
168210
12000
16640
9600
13310
15360
15500
9600
12800
18130
9510
11790
16730
8320
10320
15840
7010
8690
13340
6680
9460
11020
5900
7770
9050
High Pressure, high rensile strength,
Â
For more detail about Coil Tubing technical data the user should refer to
manufacturer Product cataloge.
SEPTEMBER 2003
PROSPER MANUAL
12 Output
The output section is used to report, export and plot data entered into PROSPER and the
results generated by the various calculation options in the program
Â
Important Note: There are two main ways of extracting data from Prosper. One
involves going through \Output\Report (described in 12.1). The second option,
which is the easiest of the two, is by selecting “Export” in the corresponding
screen where you would like to get the data from. This will allow transferring the
data to a printer, file, screen or clipboard. The last option will allow you to paste
the data directly into Excel or any other program supporting the clipboard. For
example, we would like to get the EOS data from a file into Excel. Select
“Export”:
Selecting “Print” will allow you to paste the data into Excel directly.
2 - 20
CHAPTER 12 - OUTPUT
12.1 Report
The Report option is used to prepare reports and plots from a current analysis. This section
describes how to use the reporting system with the templates provided with the system and
how to customise these templates.
12.1.1
Setting Up the Reporting System
Figure 12-1
Preferences Screen for
Report Directories Setup
Under the Preferences option on the main menu there is a File tab. Use this screen to
initialise the data relevant to the reporting system. Enter the “Location Of Report Output
Files”. This is the default directory where reports printed to file are to be placed. Also enter
the “Location Of User-Created Reports”. This is the path to a directory where user defined
report templates are to be stored.
12.1.2
Reports
The reporting interface gives you complete control over how your reports are formatted and
what information is utilised to make up the report. This is facilitated by the use of report
templates, which can be edited to suit your own requirements. You can choose to use the
default report templates provided with the system or can choose to create your own slightly
different versions of these reports. The selected templates can then be used to generate the
actual reports, which can be sent to a variety of places (printer, file or screen). The report
templates are displayed in a hierarchy and all templates which have been selected (by
double-clicking on it) show an X in the check-box beside the template name.
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CHAPTER 12 – OUTPUT
3 - 20
There are two modes for the editing of report templates: System and User. System mode
does not allow you to change any template whereas User mode allows you to create new
user defined templates from scratch or based on an already existing system report template
and also allows you to edit an existing user defined report template. Selecting User mode
also makes the User Reports section of the template hierarchy visible. The User Reports
hierarchy contains all report templates which have been tagged as being a derivation of a
system report template as well as any free standing user defined templates.
Figure 12 -2
Main Window
The reporting main window consists of four main parts: The command segment at the top of
the dialogue containing the buttons, the report selection hierarchy, the output device
selection group and the template type selection group. The output device group is only used
when printing from selected report templates.
The available commands are:
OK
Cancel
Help
Setup
User
View
Print the selected reports to the selected output device and terminate the dialogue
Terminate the dialogue
Bring up the on-line help window
Select a printer
Switches between System and User edit mode, This shows or hides the User
Reports section of the report hierarchy and enables or disables the Create and Edit
buttons. If in User mode this button shows the text ‘System’ and vice-versa.
View a previously saved native format file on-screen. This brings up a file selection
box for choosing the appropriate report and passes this file name to the Report
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Print
Create
Edit
Group
Executor
Print the selected reports to the selected output device
Create a new user report (only visible in User edit mode)
Edit an existing user report template or create a new template from a system
template (only visible in User edit mode)
Allows the grouping of report templates references and the storing of the group
information in a file for later recall. This allows batch printing of reports for any
analysis
The available output types are:
Printer
Screen
Native File
RTF File
Text File
Sent the report to the current printer
The reports are displayed on-screen in a report executor window
The reports are saved as .FR files in the output reports directory
The reports are saved as RTF files in the output reports directory
The reports are saved as tab delimited text files for easy spreadsheet import
The native (.FR) file format can only be read by the reporting system whereas the RTF
format can be read by many Windows word processing applications. When printing to file
you will be presented with the following dialogue:
Figure 12 -3
File naming
window
The default directory will be set to the default output directory but this can be altered using
the Select Directory button. This can then be applied to all output files by using Change All. If
it is necessary to change the output directory of one of the files, this can be achieved by
using the Browse button (button that shown on the right side of the filename box) associated
with each report. The filenames can themselves be edited in the text box, which contains
them.
For any given report in the system hierarchy you can choose to view or print a report using
either the system report template provided or a user defined report template based on that
system report template (or at least that position in the hierarchy) or you can choose a report
grouping which can be made up from a combination of user and system reports. You choose
between these options using the report template type selection group at the bottom right of
the main window. If you select the user report template option for any hierarchy position and
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there are multiple user defined report templates for that position then a dialogue appears
which allows you to select the particular template that you want.
Figure 12-4
User-Defined Report
Template Selection
Dialogue
Double clicking on any of the report templates (or selecting and pressing Ok) will cause it to
become the user defined report template for that hierarchy position for the current reports
session. The default choice is the topmost user defined report template. You can stop a user
defined report template from being associated with that hierarchy position by selecting it and
then pressing Delete. This does not actually delete the report template (it can still be seen
within the User Reports section of the hierarchy).
If you are selecting a report grouping then a similar dialogue appears and you can select the
appropriate group file. After you have selected a file all the reports referenced in the group
will appear ‘checked’ in the hierarchy and you can then press print for all of these reports to
be sent to the selected output device.
Template Editor Commands
The template editor works on the principle of moveable fields or groups of fields where the
inputs to these fields can be any value from PROSPER. You can define headers and footers
which can be shown on each page, have fields which have a value which is the result of a
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Figure 12-5
Template
Editor Window
Data fields from PROSPER are added using the F2 key, selecting the data items required and
then pressing Ok when finished. The selected data items will then appear as fields, one by
one, as the left mouse button is clicked. You can roughly position the fields in this way. You
are not limited to one pass at adding data items to the report template. More items can be
added at any time in the same manner.
Once a field has been added to the report template you can edit some of the properties of
the text which will be shown in the field and assign a group number to the field by double
clicking the left mouse button on it and the font properties can be changed by double clicking
the right mouse button on it. Other properties, such as whether the field has a box around it,
etc., can be changed through the menu options, a full description of which are given below.
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Figure 12-6
Selection of data items
The template editor commands can be selected by using the menu, toolbar or keyboard
shortcuts. You can get help on any menu item by highlighting the menu item and then
pressing the F1 key or by consulting the index of help topics under the help menu.
File Menu
This menu contains commands for saving the current report template file and specifying the
report template parameters.
Save:
Use this selection to save the current report template to the current file name. If a file is not
yet specified, the form editor will prompt you for a file name. If you do not provide a file
extension, the editor automatically appends a .FP extension to the report file. If a file with the
same name already exists on the disk, the form editor will save the previous file with a
backup extension (.RE).
Save As:
This selection is similar to Save File. In addition, it allows you to save the report template to
a new file name.
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Report Parameters:
This option allows you to set certain report parameters. Firstly, you can specify the name of
the report. You can set the margin for the printed page. You can instruct the report executor
to print trial records for adjusting forms such as labels and invoices. You can also specify the
default date format for input. The date format that you specify here will be enforced for
parameter input during the report execution session, and any date constant used in
expressions.
Report Filter:
This option allows you to enter a filter criterion for the report. Each data record will be tested
with the expression that you provide here. A record is selected only if this expression
evaluates to a TRUE value. For example, if the expression was sales->amount>100, then
only the records with the sales amount more than 100 will be selected.
Printer Setup:
This option allows you to select a printer from a list of installed printers and invoke a printer
specific dialogue box for the selected printer. You select the parameters from a set of printer
specific options. These options include page size, page orientation, resolution, etc. The
printer options that you select here determine the width and height of the report.
Exit:
Use this function to exit from the form editor session. If the current file is modified, you will
have an option to save the modifications.
Edit Menu:
This menu contains commands to edit the report objects. One or more report objects must
be selected before using this option:
Cut:
Use this option to copy the current item or all the items in the current selection to the
clipboard. The copied items are deleted from the form.
Copy:
Use this option to copy the current item or all the items in the current selection to the
clipboard.
Paste:
Use this option to paste the items from the clipboard to the current form.
Position Text:
Use this option to position the text within the item boundaries. The text can be justified on
the left, right, top, or bottom edges, or it can be centred horizontally or vertically. This option
is valid for the label and field type items only.
Item Outlines:
Use this option to specify the item boundaries (left, right, top, bottom) to draw for one or
more selected items. You can also specify the colour and width of the boundary lines.
Item Background:
Use this option to set the background colour or pattern for one or more selected items.
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Centre Horizontally:
This option is used to centre horizontally one or more selected items. When more than one
item are selected, the form editor first centres the selection rectangle and then moves the
selected items such that the position of the selected items relative to the selection rectangle
does not change.
Delete Item:
Use this option to delete one or more currently selected items. If the current section is being
deleted, the program asks for your confirmation before the deletion. All items within the
section are also deleted.
Fonts:
Use this function to change the font and colour for the text for one or more selected objects.
This option is valid for the field and label type objects only.
When you select this option, the form editor shows the font and colour selection dialogue
box. The current font and colours are preselected in the dialogue box. Use this dialogue box
to specify your selections.
Snap to Grid:
This option allows you to turn on or off the invisible grid on the form. When the grid is turned
on and an item is moved, it automatically aligns to the closest grid location. This option also
allows you to set the grid width.
Report Size:
The following options shrink or elongate the report in the horizontal or vertical direction by
the amount equal to the width or the height of the selection rectangle.
Expand Horizontally
Use this option to create horizontal space by moving items horizontally. For example,
consider three items, A, B, and C placed horizontally. If you need to insert a new item
between the items A and B, you can use this function to create the desired space between
these two items and place the new item in the newly created space. To move the items B
and C toward right, create a selection rectangle after the item A and select this option. The
width of the selection rectangle specifies the movement of the items B and C toward right
(noted that the selection rectangle does not need to include all items to be moved). All items
toward the right of the selection rectangle and with the vertical placement between the
vertical space spanned by the selection rectangle are moved.
Expand Vertically
Use this option to create additional vertical space by moving the items downward. For
example, consider three items, A, B, and C placed vertically. If you need to insert a new item
between items A and B, you can use this function to create the desired space between these
two items and place the new item in the newly created space. To move items B and C
downward, create a selection rectangle below the item A and select this option. The height
of the selection rectangle specifies the downward movement of items B and C (noted that
the selection rectangle does not need to include all items to be moved). All items below the
selection rectangle are moved.
This option also expands (vertically) the current section by the height of the selection
rectangle.
Compress Horizontally
Use this option to delete extra horizontal space by moving items horizontally. For example,
consider three items, A, B, and C placed horizontally. You can use this function to bring
items B and C closer to the item A. To move items B and C toward left, create a selection
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rectangle after the item A and select this option. The width of the selection rectangle
specifies the movement of items B and C toward left (noted that the selection rectangle does
not need to include all items to be moved). All items toward the right of the selection
rectangle and with the vertical placement between the vertical space spanned by the
selection rectangle are moved.
Compress Vertically
Use this option to delete vertical space by moving the items upward. For example, consider
three items, A, B, and C placed vertically. You can use this function to bring items B and C
closer to the item A. To move items B and C upward, create a selection rectangle below the
item A and select this option. The height of the selection rectangle specifies the upward
movement of items B and C (noted that the selection rectangle does not need to include all
items to be moved). All items below the selection rectangle are moved.
This option also shrinks (vertically) the current section by the height of the selection
rectangle.
Field Menu:
This menu contains options to insert, modify, delete and maintain fields.
Insert New Fields:
Data Field: This option is used to paste a new data field to the report template. This option
will display a list of data files and data fields to choose from. When you select a field, the
form editor displays a positioning rectangle. Use the mouse to position the field rectangle
and click any mouse button. The current field attributes can be changed using the Edit
Current Field Option.
Calculation Field: This option is used to paste a calculation field to the report template. This
option will prompt you for the name of the field, and the field expression. The field
expression can contain any number of valid operators, functions, system fields, dialogue
fields, and data fields. The field type is determined by the result of the execution of the field.
After you enter the field expression, the form editor displays a positioning rectangle. Use the
mouse to position the field rectangle and click any mouse button. The current field attributes
can be changed using the Edit Current Field Option.
System Field: This option is used to paste a system field to the report template. This option
will display a list of system fields (d
CHAPTER 12 – OUTPUT
11 - 20
(see Insert Calculation Field). The option shows the existing calculation expression and
allows you to make any modifications.
Edit Dialogue Field Table:
Create: This option is used to create a new dialogue field. Once a dialogue field is created, it
can be inserted in the report by using the Insert Dialogue Field selection.
A dialogue field is used to prompt the user for data during report execution. For example,
you may like your user to enter the begin and end dates for the report. A dialogue field can
be used in the field expressions and can be inserted in the report template for information
purposes. You can use a dialogue field in the report filter to reject records not meeting a
specific user criterion.
Modify: This option is used to modify the user prompt, width and prompt order of a dialogue
field. The prompt order determines the order at which the dialogue fields are presented to
the user for data input.
Delete: This option is used to delete a dialogue field from the dialogue field table. You
cannot delete a dialogue field that is being currently used in the report.
Section Menu:
This menu contains commands to insert, edit and delete report sections.
New: This option is used to create a new section. A section is identified by the section
banner and the separation line at the bottom of a section. There are three basic types of
sections. A header section displays the data that remain constant or changes only when a
sort field changes. The detail section displays the transaction record fields. A footer section
is used to display totals and summary information. ReportEase allows up to 9 header and
footer sections. A higher numbered header section is allowed only when all the lower
numbered headers are already selected. Similarly, a footer section is allowed only when the
corresponding header section is already selected.
Edit Current: This option is used to modify the properties of the currently selected section.
For the 'detail' section, you can specify the number of records to print across the page. This
option can be used to print multiple address labels across the page.
Sort Field: This option is used to specify a sort field for a header section. A sort field is used
to sort the data records.
Break Field: This option is used to specify a break field for a header section. The break field
is used to determine a sort break. Typically, the break field would be the same as the sort
field. However you can specify the break field differently from the sort field. You can also
specify a calculation expression for a break field.
Filter: This option is used to enter a filter criterion to print a section. Normally, every section
included in the report template is printed in its appropriate sequence. However, if you wish to
print a section depending upon a condition, you can enter this condition expression using
this option. The expression must evaluate to a logical value (TRUE or FALSE). During the
report execution, the section will be printed only if the expression evaluates to a TRUE
value.
Line: This menu contains commands to create and edit a line object:
Create a Line: Use this option to draw a line. When you select this option, the form editor
displays a positioning rectangle. Use the mouse to position the rectangle and click any
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mouse key. The line will be drawn within the position rectangle. The line size can be
changed using the sizing tabs.
Edit Current Line: Use this option to edit the angle, colour, and thickness of a 'line' type
object.
Label: This menu contains commands to create and edit a label object:
Create a Label: Use this option to create a new label. When you select this option, the form
editor displays a positioning rectangle. Use the mouse to position the rectangle and click any
mouse key. The 'label' object will be created within the positioning rectangle. By default, the
form editor inserts the text 'label' in the label item. The label text can be edited in the editing
window.
Edit Current Label: A label text can be edited by simply selecting the desired label item and
clicking on the edit window.
As you insert or delete the text, the length of the label text changes. Normally, the form
editor will automatically adjust the item box boundaries to completely enclose the new text.
However, this automatic size adjustment ceases if you manually resized the item boundary
by pulling on the sizing tab. This feature can be used to enclose the text in an item box
larger than the default size.
Picture: This menu contains picture import functions:
Import Picture from Clipboard
Use this command to copy a picture bitmap from the clipboard.
When you select this option, the form editor creates a positioning rectangle equal to the
dimensions of the picture. Use the mouse to position the picture rectangle and click any
mouse key. The picture will be placed within the position rectangle. The picture size can be
changed using the sizing tabs.
Import Picture from Disk File
Use this command to read in a picture bitmap from a disk file.
When you select this option, the form editor creates a positioning rectangle equal to the
dimensions of the picture. Use the mouse to position the picture rectangle and click any
mouse key. The picture will be placed within the position rectangle. The picture size can be
changed using the sizing tabs.
Arrange:
This menu contains commands to align, size and space a set of selected objects:
Alignment At:
Horizontal Top Edge:
Use this option to horizontally align the top edge of the selected items to the top edge of the
leftmost item in the selection.
Horizontal Bottom Edge:
Use this option to horizontally align the bottom edge of the selected items to the bottom edge
of the leftmost item in the selection.
Horizontal Centre Line:
Use this option to align the horizontal centre line (imaginary) of the selected items to the
centre line of the leftmost item in the selection.
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Vertical Left Edge:
Use this option to vertically align the left edge of the selected items to the left edge of the
topmost item in the selection.
Vertical Right Edge:
Use this option to vertically align the right edge of the selected items to the right edge of the
topmost item in the selection.
Vertical Centre Line:
Use this option to align the vertical centre line (imaginary) of the selected items to the centre
line of the topmost item in the selection.
Even Spacing:
Horizontally:
Use this option to place the selected items horizontally at an equal distance from each other.
The inter-item distance is equal to the distance between the first two leftmost items.
Vertically:
Use this option to place the selected items vertically at an equal distance from each other.
The inter-item distance is equal to the distance between the first two topmost items.
Even Sizing:
Width:
Use this option to change the width of the selected items to the width of the topmost item.
Height:
Use this option to change the height of the selected items to the width of the leftmost item.
Undo Previous Arrangement Command
Use this function to undo the previous arrangement command.
Report Executor CommandsThe report executor allows you to view reports that have been
generated and saved to a native format file. It is invoked by using the view option from the
reporting main window and selecting a file from the file selection box. The file selection box
will point to the default data directory and will have the filter extension set to the correct file
type (.FR).
Figure 12-7
File Selector
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Figure 12-8
Report
Executor
The options available on this window are:
Jump:
Go to a particular page in the document.
Print: Send the document to the defined printer.
Preview:
Look at the page layout of the document.
Save:
Save the document to a file (native and RTF).
Exit:
Quit the current window.
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12.2 Export
An export can be made either directly from individual parts of the program, or from the
Output | Export menu option. This section describes how to customise exports.
12.2.1
Export Setup
Use the main menu Output | Export option to export data from a current analysis, or from a
previously saved .OUT file. When you click Export a series of screens leads you through the
process of selecting the data required for your export. To include a section of data, click the
check box to the left of a particular item and, depending on the selection, further input
screens will be presented. This process ensures that only relevant sections are exported. A
sample export dialogue box is shown below:
Figure 12-9
Report Setup Dialogue
After entering your choices, Click OK to return to the main export dialogue box. You must
then select a destination for your export data. Clicking Print initiates generation of the data
and sends it to your selected destination. Setup accesses a screen for selecting fonts,
margins etc. as in the Plot menu (Section 12.1). The font selections made for export data are
independent of the plotting fonts.
Exported data can be sent to your choice of:
•
Printer -
the primary printer as set up under Windows.
•
File -
Creates an ASCII data file and saves it. Clicking Print displays a
dialogue box that requests a file name and destination. Enter a
suitable file name (PROSPER automatically appends a .PRN
extension) and click OK to save the file. The Fixed Format option
saves a file in a printer ready format that can be imported into a DOS
based word processor. Use the Tab Delimited format to save a file
suitable for importing directly into a spreadsheet such as EXCEL.
•
Clipboard -Clicking Print after selecting this option copies the exported data onto
the Windows clipboard. From the Clipboard, you can view, edit and
paste the data directly into another Windows application. e.g. a word
processing program.
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•
Screen -
Clicking Print after selecting this option allows you to view the
exported data on the screen. Scroll through the data using the
scrolling thumbs or arrows. When finished viewing, click OK to return
to the main menu.
Once a .PRN file has been saved, further copies of the exported data can be made using a
word processor from outside PROSPER. To ensure that printed exports are correctly
formatted, only non-Proportional fonts can be selected for export data. The fonts on the
export setup screen are independent of those selected on the plot setup screen.
Â
PROSPER’s default font selection will give good results on most printers.
Choose another font if you have problems printing reports.
Calculation and Export Data Layout
Screen and hardcopy exports can be customised to display only the required variables. For
complex calculations, this can save printing large amounts of irrelevant data and detailed
reports can still be produced when required. To use the Layout feature, firstly complete a set
of calculations. The following example is for PVT calculations.
Click the Layout button on the calculation results screen and select the variables to display
from the layout screen:
Figure 12-10
Calculation Layout
Show All and Hide All buttons are used to make changes to the entire list of variables.
Individual variables can be selected or de-selected by clicking them directly. When you click
OK, only the selected variables will be displayed on the calculation screen.
In addition to the calculation results screens, Layout also controls the variables displayed in
Output  Export (to file, clipboard, printer).
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12.3 Plot
A plot can be made either directly from individual parts of the program, or from the Output |
Plot menu option. This section describes how to customise plots for both the screen and
hard copy. From the Plot Output main Window select the plot you want to see by highlighting
it in the list of available plots and then press the Plot button or simply double-click on the
appropriate plot
Figure 12-11
Plot Output Setup
Zooming
Plots can be zoomed simply by placing the mouse pointer (which changes to a pair of cross
hairs over the active plot area) at the corner of the region you wish to enlarge, then dragging
until the area of interest is enclosed by the zoom box. Release the mouse button and the
outlined area will be zoomed to fill the entire plot area.
12.3.1
Plot Command Summary
Finish
Returns you to the previous menu. Use Finish when you have finished working with a plot.
Scales
PROSPER normally picks appropriate scales to display your data. Use Scales to enter
custom upper and lower limits for both X- and Y- scales. To display round numbers on the
intermediate grid lines, ensure that the span of your upper and lower plot limits fits evenly
with the number of plot blocks set in the Options menu.
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Replot
Re-plots the graph using the original scales. Use this option to un-zoom a plot.
Output
Selects the output options menu. Plots can be output to the Windows clipboard, a Windows
metafile or a hard copy device in colour, grey scale or monochrome formats. Plots can then
be pasted directly from the clipboard into other Windows applications such as a word
processor. Windows metafiles can be saved and read by a variety of applications. If hard
copy is selected, the following hard copy options screen will appear:
Figure 12-12
Hard Copy Options
Select your desired plot options and click Print to output the plot. Depending on the actual
hard copy device connected, you may need to experiment with font styles and sizes. Note
that some fonts cannot be rotated, and are unsuitable as a Vertical font. If Y-axis labels are
being plotted horizontally, try a different font selection. Return to the plot menu by clicking
OK.
Colours
This option enables you to customise the colour of any item on the plot. Note that laser
printers and monochrome monitors will often produce better results if colour plotting is
disabled. A sample colour customising screen is shown below:
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Figure 12-13
Change Colours
Options
The Options button enables you to customise the overall appearance of the plot screen and
select font type and size etc. A sample options screen is shown below:
Figure 12-14
Plot Options
Some plots include a results box on the screen. If the default position of the box interferes
with the plot, it can be moved by holding down the Shift key and using the mouse to drag it
to another location. The fonts selected on the Plot options screen apply only to plots. The
export data fonts are set up on a separate screen.
Variables
Use this button to select variables for plotting. The variables available change according to
the type of calculations that have been completed and the particular plot type that has been
selected. Where applicable, extended plot variables can be selected.
Test Data
Clicking Test data displays a screen in which you can enter up to 10 measured data pairs.
Once the test data has been entered, it can be displayed together with the calculated data
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when the plot is re-drawn. If the current .OUT file is subsequently saved, the test data will
also be saved and will appear on subsequent plots.
Help
Accesses the on-line Help system. See Section 14 for more details of the Help system.
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13 Units
This chapter describes the system of units. The built in flexibility of the units system
enables you to select any variable and define the unit of measurement to be used. This
feature makes it possible to modify the units system so that it corresponds to data reports
supplied by a service company or customise the units system to suit your own personal
preferences.
PROSPER always works internally in Field units. To facilitate data entry and output display
in any units system, PROSPER accepts data in the specified Input units and converts it to
Oilfield units for calculation. The results (in Field units) are converted back to the specified
Output unit set if necessary. By making selections from the different categories, you can
work in the units you prefer and save the results in the units required by company policy.
Figure 13-1
PROSPER Units System
The changes made to the units system are retained in the program memory and apply to
all files opened during the current processing session. The program allows you to create
your own units system. To access the units system, point to the Units menu and click the
mouse, or press ALT U. A choice of Units Summary or Units Detailed is presented. Units
Summary is the main Units system. Use Units Detailed to specify display precision for
individual unit types.
13.1 Units Summary
Select Units Summary to display the following screen:
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CHAPTER 13 –THE PROSPER UNIT SYSTEM
Figure 13-2
Units Summary
The Units Summary screen is divided into two main sections:
Variables
Select any item from the list of variables displayed. To select an item, move the scroll box
up or down, until the required variable appears on the screen.
Validation
Used to set up the error checking limits for each selected input variable.
Click on the Details buttons to the right of each variable name in order to view the details of
each particular variable.
13.1.1
Unit Systems
The user can change the units system form tool bar menu
Figure 13-3
Units Summary
The following default Units Systems are provided:
•
Oilfield Units
•
Norwegian S.I.
•
Canadian S.I.
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CHAPTER 13 - UNITS SYSTEM
•
German S.I.
•
French S.I.
•
Latin S.I.
3-5
Customised unit systems can be created and saved under new names. Different units can
be selected for both input and output.
13.1.2
Changing Unit Systems for some variables
For each variable, if the mouse points to the unit and right click, the unit system can be
changed; this option is available at screen for any input variable.
Figure 13-4
Units system
13.1.3
Changing the Units
The Input and Output units for each variable on the list can be changed.
To change or customise the default Units System:
•
Scroll through the measurement variables list until the unit item to modify is
visible on the screen.
•
Select the unit category (Input and/or Output) to modify.
•
Select the unit field corresponding to the measurement item and click on the
arrow to its right to display the list of unit options.
•
Select the preferred measurement unit.
To save changes, click Save. You will be prompted to enter a name for the new Units
System. This new system can now be recalled and applied to any file. Custom unit sets
can be erased by clicking the Delete button, then selecting the unwanted units system.
The ability to have separate input and output unit systems allows the user to work with
familiar units and to create reports or export data in any required unit system. PROSPER
calculates them internally in Oilfield Units. To validate unit conversion factors, click the
button located to the right of the particular variable and the multiplier and shift used for unit
conversion will be displayed.
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Clicking Report  Print will create a summary report of conversion factors in use.
If some particular units have been modified during the course of a PROSPER session, the
changes will be written into the .SIN file when the input data are saved. Irrespective of the
current units system settings, recalling a previously saved .SIN file will cause PROSPER to
revert to the units saved in the recalled .SIN file. To permanently impose a new set of units
on the recalled file, open a custom units file (or use one of the internal unit sets) and then
save the .SIN file. The new units settings will be used whenever the .SIN file is loaded.
13.1.4
Validation Limits
To reduce the possibility of entering incorrect data, PROSPER checks that input data falls
within predetermined validation limits. For most purposes, the default validation limits are
adequate. For particular applications, the user can change the validation limits if required
by entering new values directly from the units definition screen.
Find the required variable by scrolling through the list, and then enter required changes in
the low and high validation limit boxes. Enter your custom validation limits in the units
currently in use. To permanently attach the new validation limits to a custom units system,
click Save before leaving the validation screen by clicking OK.
PETROLEUM EXPERTS LTD
CHAPTER 13 - UNITS SYSTEM
5-5
13.2 Units Detailed
The purpose of the Units Detailed screen allows adjustment of the precision of data display
for both input and output to be adjusted individually for each unit type. To set display
precision, select Units Detailed. Scroll though the available units until the required one is
shown in the Current box as shown in the following example:
Figure 13-5
Units Detailed
Input and Output units can be selected from this screen. Validation limits can be entered
for the selected units. The Options panel enables you to set the number of decimal places
to display for each unit type.
13.3 Units Reset
Use this option to quickly reset the units system back to default values. To specify what
Units defaults are please go to the Units Tab in the Preferences screen (File |
Preferences).
SEPTEMBER 2003
PROSPER USER GUIDE
14 Help
PROSPER has an on-line help facility which enables you to get information quickly about a
menu option, input field or function command. This facility enables you to display
instructions for completing a particular task or input field without exiting from the current
screen. The help windows offer a list of topics which not only include definitions and
functions specific to PROSPER but details on using some features of Windows as well.
To use the PROSPER on-line help system, the help file must be located in the same
directory as the program. If you are new to Windows, information on using the help system
can be made available when selecting the Help option in the PROSPER main menu and
choosing 'Using Help'. This will display a help screen from which the information you need
can be selected from a list of topics.
The Help facility has function buttons located at the top of the windows, which can be used
to navigate within the help system. If a particular feature is not currently available, the
button associated with that function is dimmed. Information on specific help topics may
lead to other related topics. Some words in the Help windows are marked with a solid
underline and appear in colour (green) if you use a colour screen.
These words are called jump terms and can be used to move around Help more quickly.
When you click a jump term, Help will move you directly to the topic associated with the
underlined word(s).
14.1 Finding Information in Help
There are three ways of finding the information you need:
14.1.1
Use the Search feature in Help
This facility is useful for finding specific information about using the keyboard. For example,
the keys used for text selection. Type in the phrase "text selection" and search the system
for the phrase or select the topic from the list displayed.
14.1.2
Use the Help Index
This option is useful for viewing specific sections listed in the Help index. Go to the topic or
command you are interested in and select the item you need.
14.1.3
Context Sensitive Help
This feature can be used while you work to give you information about a particular menu
option.
2-3
CHAPTER 14 -
14.2 Accessing Help
To get information quickly about a specific menu option or entry field in PROSPER, the
following methods will display the help facility:
14.2.1
Help Through the Menu
From the menu bar in PROSPER, click on Help (or ALT H) and select Index. From the list of
help topics, select what you want to see by pointing to the specific item.
14.2.2
Getting Help Using the Mouse
• Press SHIFT+F1
The pointer will change to a question mark.
• Choose the menu command or option.
or
• Click the Menu command or option, and holding the mouse button down press
F1.
14.2.3
Getting Help Using the Keyboard
Press the ALT key plus the first letter of the menu name, option and press F1.
14.2.4
To Minimise Help
If using the mouse, click the minimise button in the upper-right corner of the help window. If
using the keyboard, press ALT SPACEBAR N. This procedure will close the help window,
but keep the help icon on the Windows desktop.
14.3 What’s New
Click Help  What’s New to display information about new features in the program release
you are using.
14.4 Worked Examples
Click Help  Worked Examples to access online the worked examples documented in
Appendix A of this manual
14.5 Flow Correlations
Click Help  Flow Correlations to access a detailed generalised discussion about the
history and reasons behind flow correlations and issues that relate to their use in
PROSPER.
PETROLEUM EXPERTS LTD
3-3
14.6 Help About PROSPER
Click Help  About PROSPER and the following screen will be displayed:
Figure 14-1
Help About PROSPER
If you need to contact Petroleum Experts about a problem with the program, please have the
version number and creation date shown on this screen available should it be required.
SEPTEMBER 2003
PROSPER USER GUIDE
Appendix A Worked Examples
A1 Example 1 – Naturally Flowing Oil Well
File: ~/samples/PROSPER/oilwell.out
The objectives of this example are to:
• Show how production can be increased by removing skin.
• Show how production can be increased by increasing the tubing size.
• Generate lift curves for a reservoir simulator.
This example demonstrates how to:
• Match the PVT correlations to real data.
• Match the multiphase flow correlations to real data using VLP matching.
• Use IPR matching to determine reservoir pressure.
• Run a system analysis with sensitivities.
• Run a pressure versus depth gradient calculation.
• Generate vertical lift tables for a reservoir simulator.
A1.1 Defining the System
Begin by starting the program. From the PROSPER main menu, select File  New to
reinitialise the program input and output files. The ‘New’ menu item under File is only
available if a file has already been loaded.
To begin setting up the system options, select Options Options or double-click on the
‘SUMMARY DATA’ area and make the following selections:
•
•
•
•
•
•
•
•
•
•
•
•
•
Fluid:
PVT Method:
Separator:
Flow type:
Emulsions:
Well type:
Lift method:
Predicting:
Model:
Calculation range:
Display:
Completion:
Gravel pack:
Oil and Water
Black Oil
Single-Stage Separator
Tubing Flow
No
Producer
Naturally Flowing Well
Pressure and temperature (Offshore)
Rough approximation
Full System
Show calculating data
Cased Hole
No
Then click Done to exit this screen.
This completes the system setup and reinitialises the program. If the status screen is being
displayed, the main system areas (‘SUMMARY DATA’, ‘PVT DATA’, ‘IPR DATA’,
2 - 164APPENDIX A – WORKED EXAMPLES
‘EQUIPMENT DATA’ and ‘CALCULATION SUMMARY’) can be now easily accessed by
double-clicking on them.
A1.2 Entering and Matching PVT Data
The purpose of this section is to demonstrate how to match the PVT correlations to real PVT
data.
To perform a PVT match and display the results:
•
Enter the data required for the black oil correlations and the match data.
•
Calculate and plot the unmatched PVT and the correlated but unmatched data
together.
•
Match the correlations to the measured data and plot the matched PVT data.
Step-by-Step Instructions
• Select the PVT menu
• Click Input data
or
•
Double-click on the ‘PVT DATA’ area
and enter the following:
Solution GOR:
Oil Gravity:
Gas Gravity:
820 scf/STB
34 API
APPENDIX A – WORKED EXAMPLES 3 - 164
Generate unmatched correlated data for comparison by:
•
•
Clicking Done to return to the main PVT Data input screen
Clicking Calculate to access the calculation screen
Select Glaso for Pb, Rs and Bo correlation
Select Beggs et al for oil viscosity correlation.
Enter the following ranges for the calculations:
From
To
# Steps
Temperature
degrees F
210
210
1
Pressure
psig
1000
7000
51
Then:
•
•
•
•
•
•
•
Click Done
Click Calculate
When calculation is finished, click OK
Click Plot
Click Variables:
Select Pressure for the X-Axis Variable, Gas Oil Ratio for the Y-Axis Variable
Click Done to display the plot
Both the data predicted by the correlation and the measured data points are shown on the
plot below.
Figure A1.1:
Un-Matched PVT Plot
The next step is to match the correlations to the laboratory measured data. From the plot:
•
•
•
Click Main to return to the main PVT input screen.
Click Regression
Click Match All (matches all correlations and identifies which has best fit)
SEPTEMBER 2003
PROSPER MANUAL
4 - 164APPENDIX A – WORKED EXAMPLES
The program performs a non-linear regression to adjust the correlations to best fit the
laboratory data by applying a multiplier (Parameter 1) and a shift (Parameter 2) to the
correlations. Click OK when the regression is finished.
Click Parameters to display the closeness of fit for all correlations. The less correction a
correlation requires to fit the measured data, the better it is. Note that the displayed standard
deviation shows how well the matching process converges and should therefore not be seen
as sole criterion for the goodness of a match.
Standing has for this example the best overall fit for Pb, GOR and FVF whilst Beggs et al fits
best for the oil viscosity. Therefore, Standing will be selected to correlate Pb, GOR and FVF
and Beggs et al for the oil viscosity.
Click Done to exit screen.
Make sure that Standing and Beggs et al have been selected in the Correlations input box.
The matched data can be plotted by clicking Plot from the regression menu as in the
example below:
Figure A1.2:
Matched PVT Plot
All further calculations will be performed using the matched PVT data unless the match
parameters are subsequently reset from the PVTCorrelations menu
•
Click Main | Done
The names of the matched PVT correlations should appear on the PROSPER main screen
(PVT DATA area) as well as a reminder that the PVT has been matched.
This completes the PVT input and matching process.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 5 - 164
A1.3 Entering the IPR data
The next task is to enter the Inflow Performance model as follows:
•
or
Click System  Inflow performance
•
Double-click on the ‘IPR DATA’ area
•
Select the Darcy IPR method and enter the following in the IPR
Select Model screen:
Mechanical / Geometrical Skin
Reservoir pressure:
Reservoir temperature:
Water Cut:
Total GOR:
Relative Permeability:
Enter skin by hand
5000 psig (Average reservoir pressure)
210 degrees F
0 percent
820 scf/STB
No
Click on the Input Data button in the top right hand corner of the window, then enter the
following reservoir data:
•
•
•
•
•
Reservoir Permeability
Reservoir Thickness
Drainage Area
Dietz Shape Factor
Well bore Radius
50 md
200 feet
500 acres
31.6 (for a circular drainage area)
0.354 feet
Then click of the Mech/Geom Skin tab and enter a Skin of 4. Click Calculate to display the
following IPR plot:
Figure A1.3:
Darcy IPR Plot
Return to the main menu by clicking Main.
This completes the IPR definition.
SEPTEMBER 2003
PROSPER MANUAL
6 - 164APPENDIX A – WORKED EXAMPLES
A1.4 Entering the Equipment data
The next task is to define the down hole and surface equipment. Enter the well equipment as
follows:
•
Click System  Equipment (Tubing etc)
or
•
Double-click on the ‘EQUIPMENT DATA’ area
•
Then click | All  Edit
The program will automatically lead you through the required equipment data screens
starting with the well deviation survey. Enter the following into the deviation survey data
table:
Measured
Depth
(feet)
0
4300
4600
4900
11300
11400
True Vertical
Depth
(feet)
0
4273
4528
4800
10350
10430
While entering the deviation survey, PROSPER calculates automatically the cumulative
displacement and the angle of the well.
•
Click Plot to plot the well profile
•
Click Finish  Done to continue to the surface equipment screen
•
Click Cancel to enter NO surface flow line data
The downhole equipment screen will then appear. Note that the Xmas tree elevation has
been taken to be the same as the deviation survey reference.
The well has 3.958" ID tubing down to 11000 ft and 6" ID casing down to 11400 ft. Click on
the Type cells to get a combo box of options and enter the following downhole equipment:
Type
Xmas tree
Tubing
SSSV
Tubing
Casing
Measured
Depth
(feet)
0
1000
11000
11400
IDs
Roughness
(ins)
(ins)
3.958
3
3.958
6
0.0006
0.0006
0.0006
Descriptive information about the downhole equipment can be written in the label fields as
reminder.
Click Done to advance to the flowing temperature profile screen and enter the following:
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 7 - 164
Measured
Depth
(feet)
0
11400
Overall heat transfer coefficient :
Fluid
Temperature
(deg F)
45
210
8 BTU/hr/ft2/F
Click | Done.
The Average Heat Capacities screen will then appear. Click Done to accept the default
value.
This completes the equipment input for the well.
Click Summary and check that the equipment input data is consistent. As a further check
click Draw Down hole. When satisfied that the well equipment is correct, click Main to return
to the PROSPER main screen (status screen).
SEPTEMBER 2003
PROSPER MANUAL
8 - 164APPENDIX A – WORKED EXAMPLES
A1.5 Matching Menu
In this section we will:
•
Compare the predicted pressure profiles produced by the unmatched VLP
correlations.
•
Match the multiphase flow correlations to measured test data and identify which
correlation requires the least correction to best fit the measured test data.
•
Adjust the reservoir pressure to match the IPR to measured test data.
A1.5.1 Correlation Comparison
To compare the correlations:
•
Click Matching  Matching | VLP/IPR Matching (Quality check) or double-click in
the VLP/IPR Matching check-box on the “CALCULATION SUMMARY” screen
Enter the following well production data in the first row:
THP
psig
930
THT
deg F
134
Water
Cut %
15
Rate
STB/d
7200
Gauge
Depth ft
11000
BHFP
psig
3940
GOR
(Scf/bbl)
820
GOR
Free
0
After entering the data, click on the small button labelled ‘1’ just to the left of the first row of
data that you have just entered. The colour of the box should turn blue from grey. Then hit
on the button labelled ‘Correlation comparison’.
Then select VLP correlations with the Tab button or the mouse to compare from the list.
For this oil example, select Hagedorn Brown, Fancher Brown, Petroleum Experts 2, Petroleum Experts
3, and Duns and Ros Modified. Select Dukler Flannigan for the Surface Correlation even
though no surface equipment has been entered, then calculate and plot the comparison by:
•
•
•
Clicking Calculate  Calculate.
Clicking OK when the calculation is finished
Clicking Plot to display the following comparison plot:
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 9 - 164
Figure A1.4:
Gradient Comparison
In this example the measured data points lie closer to the Petroleum Experts 2 correlation. This
can be seen more clearly by zooming into the test point area (e.g. above entered measured
depth and pressure data) on the Pressure versus Depth plot by using the cursor to draw a
rectangle around the relevant areas.
Note that the calculated and measured pressures all fall to the right side of
the Pressure versus Depth plot after Fancher Brown.
Return to the VLP/IPR Matching screen by clicking on | Main.
A1.5.2 VLP Matching
VLP matching allows the multiphase flow correlations to be adjusted to best fit through a
range of measured data.
•
The program does this using a non-linear regression technique which applies
multipliers to the hydrostatic (Parameter 1) and friction (Parameter 2) elements of the
pressure drop terms of the multiphase flow correlation.
To carry out a VLP match, click on the ‘Match’ button in the VLP/IPR Matching screen.
When more than one test data points are available for flow correlation
calibration, it is recommended to use the following procedure:
•
Use minimum number of test points (possibly one) to calibrate the
correlation.
•
Check how well the calibrated model predicts the other test points
(those not used in calibration).
•
This ensures, reliability of the model in predictive mode.
SEPTEMBER 2003
PROSPER MANUAL
10 - 164APPENDIX A – WORKED EXAMPLES
Click Match and select Hagedorn Brown, Petroleum Experts 2 and Petroleum Experts 3 again from the
list of correlations if the previous selections have been removed.
Click Match to begin the matching process. This may take some time, so please be patient.
Once the calculations have finished, click Statistics to examine the fit parameters.
The table gives regression parameters of Parameter 1 = 0.999 and Parameter 2 = 0.989 for
Petroleum Experts 2, which requires the least correction and will therefore be used for further
calculations.
Click on Done | Done to get back to the VLP/IPR Matching screen.
A1.5.3 IPR Matching
This step ensures that the IPR model can reproduce the well test conditions.
•
•
From the VLP/IPR Matching screen, click the IPR button.
Select Petroleum Experts 2 as ‘Tubing Correlation’, then click on Calculate.
Note that the match parameters have been appended to the
correlation name.
PROSPER will compute the VLP curves for the match data (WHP, flow rate, water cut etc.)
using the matched VLP correlation.
Once the VLP calculations have finished, click | IPR to access the IPR input screens and
then | Calculate to plot the VLP and IPR lines.
The VLP and IPR lines intersect quite close to the measured data points.
Figure A1.5:
VLP/IPR Plot
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 11 - 164
PROSPER will use the selected VLP correlation (matched if available) to
calculate the flowing pressure at the intake node depth. This is a
convenient way to correct flowing pressures from gauge depth to the
sand face. The calculated flowing pressure can be entered directly in a
Vogel IPR if required.
We will now adjust the IPR to better match the test points.
•
The available parameters for matching depend on the IPR model in use. For the
Darcy-IPR model, permeability, skin or reservoir pressure could be used.
•
For this example, we will assume that the well P.I. has not changed - but we do not
have a recent reservoir pressure.
•
We will match the IPR by adjusting the reservoir pressure.
Click Main  IPR and enter a reservoir pressure of 4982 psig and water cut of 15%. Click |
Calculate to see a new plot. The error in bottomhole pressure is now very low.
The PROSPER well model is now matched from reservoir to sand face and surface to sand
face using the low rate test.
A1.5.4 Checking the Model for High Rate Test
Before, the model can be used for predictive runs, we will check how well does it reproduce
the high rate test, without any matching.
To do so, go to the VLP/ IPR Matching Input data screen.
Enter the high rate test results as shown below in row 2:
THP
Psig
290
•
•
•
•
THT
deg F
157
Water
Cut %
15
Rate
STB/d
12000
Gauge
Depth ft
11000
BHFP
psig
3330
GOR
(Scf/bbl)
820
GOR
Free
0
Click on IPR.
Click on Calculate, with PE2 selected as correlations to compute the VLP curves for
both the test cases.
Click on IPR to go to the IPR input screens. Do not alter any parameter here.
Hit Calculate, to generate the IPR and VLP intersection plot with the test data points.
This gives the following plot.
SEPTEMBER 2003
PROSPER MANUAL
12 - 164APPENDIX A – WORKED EXAMPLES
Figure A1. 6:
VLP/IPR Plot
The plot displayed represents the matched VLPs and the IPR.
Note that the model is able to reproduce the high rate test also with
accuracy, even though this data has not been used for calibration.
It can now be used with confidence for predicting future production performance. Click Main
 Main to return to PROSPER status screen.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 13 - 164
A1.6 Performing a Systems Analysis
Now that the PVT, VLP and IPR have been matched to measured data, we can move
onwards and perform the system analysis. Perform the Inflow and Outflow calculations to
determine the operating flowrate and pressures for a particular well as follows:
•
Click Calculation  System (Ipr + Vlp) or double-click in the ‘System’ check box on
the ‘CALCULATION SUMMARY’ screen
• Enter a Top node pressure of 250 psig and a Water cut of 0 %
• Select Dukler Flannigan for the surface flow line correlation
• Select Petroleum Experts 2 for the multiphase flow correlation (note the match
parameters have been appended to the correlation name)
• Select Bottom Node as ‘Solution Node’
• Select Automatic Linear for the rate method
• Click | Continue and enter the following sensitivity variables using the combo
boxes:
For variable 1
−
Select Water cut
Enter 0, 40, 80
For variable 2
−
Select Skin
Enter 0, 2, 4
For variable 3
−
Select Tubing/Pipe diameter
Enter 3.958, 4.892
• Click | Continue
The program now asks between which nodes should the tubing size sensitivity be run:
•
Select the Xmas tree as First Node and the bottom of the production tubing
(@11,000 ft) as Last Node with the combo boxes .
•
Click | Continue  Calculate to begin the system analysis calculation.
This may take some time, so, please be patient.
Once the calculations have finished, click Plot to take a look at the VLP and IPR curves
plotted for the range of sensitivity variables as follows:
SEPTEMBER 2003
PROSPER MANUAL
14 - 164APPENDIX A – WORKED EXAMPLES
Figure A1.7:
VLP/IPR System Plot
Click Finish and return to the system calculation screen.
Next, prepare a sensitivity plot for liquid rate as a function of skin and tubing size by:
• Clicking Sensitivity  Variables to display the plotting variables screen
• Select Liquid Rate on the Y-axis
• Select Skin on the X-axis
• Select Water Cut as the parameter variable
• Select a Tubing size of 3.958" for the third parameter
• Click | Done to display the following plot:
• Then click | Finish to exit the plot screen
Figure A1.8:
System Sensitivity Plot
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 15 - 164
The solutions points are accessible on the ‘CALCULATION OUTPUT screen in the ‘Solution’
area by selecting the concerned sensitivity variables.
These results show that:
•
For the 3.958" ID tubing a liquid production gain of around 1,960-2,340 STB/d is
possible by removing the skin for various water cuts.
•
For 0% water cut and a zero skin, increasing the tubing size increases the flow
rate by around 5,500 STB/d.
Having generated the system solution, it is possible to generate a gradient plot at any of the
solution operating points to determine the flowing gradients and flow regimes in the well
bore.
This can be done by clicking | Sens. PvD on the ‘CALCULATION OUTPUT screen or from
the main menu by selecting Calculation  Gradient (Traverse).
To generate a gradient plot at one of the operating rate/pressure solution points, carry out
the following selections on the ‘CALCULATION OUTPUT screen:
•
•
•
Water cut:
Skin:
Tubing size:
40%
0
3.958"
The system solution rate and pressure for the chosen combination will be displayed. Check
that the first and last nodes correspond to the Xmas tree and Casing (@ 11,400 ft), then
compute the gradient by:
•
•
•
•
•
Clicking | Continue | Calculate to start the calculation
Click Plot to display the data on a plot
Click Variables
Select True Vertical Depth on the Y-axis and Pressure and Temperature on the
X-axis
Click | Done to display the following plot:
SEPTEMBER 2003
PROSPER MANUAL
16 - 164APPENDIX A – WORKED EXAMPLES
Figure A1.9:
Sensitivity P Vs D
Click | Main | File | Save As | Input And Analysis Data (.ANL), then save the file called
OILWELL.ANL for use in the next section.
A1.7 Generating VLP Lift Tables for Simulators
Firstly, not already done, open OILWELL.ANL, then
•
•
•
Click Calculation  VLP (Tubing Curves) | 3 variables
Select same correlations as used in the system calculation
Select Rate Method - User Selected
If wellhead pressure is used for production allocation, select Xmas tree (node 1) as the top
node and Node 9 (@11,400 ft) as the last node. Enter a first node pressure of 250 psi and
water cut of 0%. Enter liquid rates of 100,500,1000,2000,4000,8000,16000 STB/d. Click |
Continue and enter the following sensitivity variables:
•
•
•
•
Select First node pressure for variable 1 and - enter 200, 600, 1000, 3000
Select Water cut for variable 2 and - enter 0, 40, 80
Select Gas Oil Ratio for variable 3 and - enter 400, 820, 2000 scf/STB.
Click | Continue  Calculate to start calculating VLP curves.
This may take a while, so please be patient.
To export the curves to GAP or MBAL (TPD-format):
•
•
•
•
Click Export
Select Petroleum Experts GAP/MBAL, then click | Continue
Enter a file name and click | Save to save the lift curves as a tpd-file
Return to the main menu by clicking Main.
If you wish to refer to this example later, go to the file menu and save this example under a
new name e.g. OILVLP.out
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 17 - 164
A2 Example 2 - Gas Lift Design
File: ~/samples/PROSPER/gaslift.out
The objectives of this example are to:
• Find the maximum production rate achievable using gas lift.
• Determine the optimum lift gas injection rate and depth.
• Design the operating and unloading valves.
This example demonstrates how to:
• Setup the gas lift design parameters.
• Calculate the design production and gas injection rates.
• Space out the valves.
• Determine the valve trim sizes and dome pressures.
• Calculate production sensitivities using the gaslift design.
The same well as used in the Oilwell example will be used. The design assumes that the
reservoir pressure will drop to 4000 psig and that the water cut will rise to 80%.
This example will guide you through opening the existing OILWELL.ANL file, changing the
calculation options and reservoir conditions, performing the design and finally saving the file
under a new name.
To perform the gas lift design, firstly open OILWELL.ANL, then follow these procedures:
Edit existing or input new data as required:
•
•
•
•
Select the Options menu.
Change the lift method to Gas lifted (no friction loss in annulus)
Click on | Done to get back to main
Go to System Equipment and check the edit box for Geothermal Gradient. Enter
the following data:
Formation
Measured
Depth
(ft)
0
11400
Formation
Temperature
(deg F)
60
210
Enter an Overall Heat Transfer Coefficient of 8.5 BTU/hr/ft2/F. Then click on | Done.
SEPTEMBER 2003
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18 - 164APPENDIX A – WORKED EXAMPLES
Average Heat Capacities
Select the Average heat capacities check box, click Edit to check that the heat capacity
values are set to their default values as follows:
Cp Oil
Cp Gas
Cp Water
0.53
0.51
1.00
BTU/lb/F
BTU/lb/F
BTU/lb/F
Then click on | Done. Use | Summary to check the input data, then click | Main to return to
the Main menu.
The next step is to modify the inflow to model future conditions requiring gas lift.
• Select the System Menu and click Inflow performance
• Change the reservoir pressure to 4000 psig. Click on | Done to exit
• Click System  Gas lift data and enter the following:
Gas lift gravity 0.8.
There is no CO2, H2O or N2, so leave blank
For performing a gas lift design, the gas lift method and GLR injected can be ignored at this
stage.
•
Click | Done and leave the gas injection depth set to zero
A2.1 Setting up the Gas lift valve database
•
•
•
Select Gas lift valve database from the | Design | Gas lift menu
Add example records by clicking on Add
Enter the following valve data (for example purposes only)
Manufacturer
Valve Type
Type Spec
Spec
valve1
valve1
valve1
valve1
valve1
valve1
Casing
Casing
Casing
Casing
Casing
Casing
R20
R20
R20
R20
R20
R20
Monel
Monel
Monel
Monel
Monel
Monel
Port size
/64
8
12
16
20
28
32
R Value
0 017
0.038
0.066
0.103
0.200
0.260
Alternatively, you can Import the valve data from the sample VALVES.GLD
file that can be found in the \SAMPLES subdirectory.
•
Click on | Done and return to the main menu.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 19 - 164
A2.2 Setting up the Design Parameters
Entering the gas lift design parameters:
•
•
•
•
•
•
•
•
•
•
Select | New well from the | Design | Gas lift menu
Select Valve type
Casing sensitive
Enter Casing pressure drop per valve
50 psi
Select Design rate method
Calculated
from
maximum
production
Select Dome press. corr. above 1200 psi to Yes
Set the Maximum liquid rate to
15,000 STB/day
Select Valve Settings
All valve PVo= Gas pressure
Select Vertical Lift Correlation
Petroleum Experts 2
Select Surface pipe Correlation
Dukler Flannigan
Select Using IPR for Unloading
Enter the gas lift design input data:
•
Maximum gas available
5 MMscf/d
•
Maximum gas while unloading
5 MMscf/d
•
Flowing top node pressure
200 psig
•
Unloading top node pressure
200 psig
•
Operating injection pressure
1500 psig
•
Kick off injection pressure
1500 psig
•
Desired dP across valve
200 psi
•
Maximum depth of injection
11000 ft
•
Water cut
80 %
•
Minimum valve spacing
300 ft
•
Static gradient of load fluid
0.46
•
Minimum transfer dP
5%
•
Maximum port size
32 (set by valve series selection)
•
Safety for closure of last unloading valve 0 psig
Figure A2.0:
Gas Lift Design
Input Data
Determine the maximum gas lifted design production rate as follows:
SEPTEMBER 2003
PROSPER MANUAL
20 - 164APPENDIX A – WORKED EXAMPLES
•
•
•
•
•
•
•
Click Continue
Select valve manufacture as Valve 1
Select valve type as r20
Select specification as Monel
Click | Done
Click | Get Rate (PROSPER calculates the maximum design production rate)
Click Plot to display the performance curve.
Figure A2.1:
Gas lift Well Performance
Curve
The program has found that around 1460 STB/d of oil could be produced with 5.0 MMscf/d
of lift gas injected at the optimum depth of injection. Click on | Finish to exit the plot.
Next, determine the position of the Unloading and Operating valves:
•
•
Click Design - the program will iterate on the design depths
Click Plot (to display the valve depths)
Figure A2.2:
Gas lift design gradient
plot
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 21 - 164
Note down the ‘Actual Gas Injection rate’, ‘Actual Injection pressure’ and ‘Actual Liquid rate’
from the graph. Having determined the number of valves and their depths, the next task is to
calculate the valve test rack setting pressures as follows:
•
Click Results to display valve depths and pressures
•
Click Calculate to display the opening and closing pressures together with the
test rack setting pressures.
Figure A2.3:
Gas lift design valve
details
The number of valves required to pass the design lift gas rate is shown at the left of the
screen. Click on the scroll arrows to see the selected port sizes, gas injection rates, etc.
Click Main to return to the main screen, then generate a report to make a hard copy of the
gas lift design.
A2.3 Calculating Sensitivities
To run sensitivities on the design for e.g. different reservoir pressures, water cuts, etc. the
gas lift design must be transferred to the System  Gas lift equipment as per the following
procedure:
• Return to the main menu
• Click System  Gaslift data and select Valve depths specified as the gas lift
method.
• Enter the following:
Casing pressure
dP across valve
•
(Enter the ‘Actual injection pressure’ that you have
noted down earlier)
200
psi
Click Transfer  From Gaslift Design  OK. The design valve depths will appear
in the table as below:
SEPTEMBER 2003
PROSPER MANUAL
22 - 164APPENDIX A – WORKED EXAMPLES
Figure A2.4:
System Gas lift data
valve depths
•
Click | Done to return to the main menu.
PROSPER now has the valve depths and surface injection pressure, but since GLR Injected
is still set to zero, no gas is being injected in the calculations. The rate of lift gas injection
will be set using a sensitivity variable.
To calculate sensitivities, click Calculation  System, then select the following:
•
•
•
•
•
Top node pressure
Water cut
Surface equipment correlation
Vertical lift correlation
Rate method
•
Click | Continue and enter the following sensitivity variables:
200
psig
80
percent
Dukler Flannigan
Petroleum Experts 2
Automatic – Linear
For variable 1
−
Select Gaslift gas injection rate
(Enter the ‘Actual Injection rate that you have noted down
earlier)
For variable 2
−
Select Water Cut
Enter 80%, 90%
For variable 3
−
•
Select Reservoir Pressure
Enter 4000, 3500.
Click Done and Calculate to calculate system sensitivities.
When the calculations have stopped, Click | Solution Details to examine the solution for 80%
water cut and 4000 psi reservoir pressure. Check that the system solution rate is compatible
with the ‘Actual Liquid rate’ that you have noted down earlier.
Click through the solutions and check the solution for 90% water cut and 3500 psi reservoir
pressure. This design is still capable of injection at the deepest (orifice valve) and the
production rate is around 400 BOPD. The sensitivity calculations show that the design is
suitable for the expected future producing conditions.
For use in Example 3, save this file as GASLIFT.ANL.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 23 - 164
A3 Example 3 - Well and Flow line Modelling
File: ~/samples/PROSPER/flowline.out
The objectives of this example are to:
•
•
•
Model a flowline using PROSPER.
Apply the Rough Approximation temperature model.
Examine the effect of the flowline on production rate sensitivities.
To set this problem, open GASLIFT.ANL and make the following changes:
Options Menu
Predict
Temperature Model
Pressure and Temperature on land
Rough Approximation
Click | System | Equipment (tubing etc), select the following categories and enter the
required data:
Surface equipment
The flowline consists of 8 miles of 6" ID pipe. Make the entries as shown on the following
screen:
Figure A3.1:
Surface Equipment Input
Click | Done | Summary and check the equipment data has been correctly entered.
SEPTEMBER 2003
PROSPER MANUAL
24 - 164APPENDIX A – WORKED EXAMPLES
Gaslift data
Return to the main menu and click System  Gaslift Data. Select Fixed depth of injection as
the gas lift method, click Continue and enter an injection depth of 7535 ft. The injection gas
gravity should remain at 0.8 s.g.
When we use FIXED DEPTH OF INJECTION in PROSPER, this option
assumes that it is possible to unload the well down to the operating valve
and that sufficient casing pressure is available to inject gas at the specified
depth.
Click | Done and return to the Main menu.
A3.1 Calculating the System Solution
To find the well flow rate, click Calculation  System. Select the following:
•
•
•
•
•
•
Top node pressure
Water cut
Surface equipment correlation
Vertical lift correlation
Rate method
Rate type
100 psig
80 percent
Dukler Flannigan
Petroleum Experts 2
User selected
Liquid rates
Use the Generate feature to enter the calculation rates. Click Generate and enter 100 and
10,000 STB/day for the minimum and maximum rates. Enter 10 for number of rates then
click | Done and PROSPER will fill in the rates table. Click | Continue and enter the following
sensitivity variables:
For variable 1
−
Select Gaslift gas injection rate
Enter 1,2,3,4,5,6
For variable 2
−
Clear any existing entries by Pressing “ Reset”
For variable 3
−
Clear any existing entries by Pressing “ Reset”
Click | Continue, and | Calculate to start the calculations.
•
The long flow line will slow the calculations, so please be patient.
Once the calculation has stopped, click Sensitivity  Variables and select Oil Rate. Click |
Done to display the following plot:
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 25 - 164
Figure A3.2:
System Sensitivity
Note that the production rate is relatively insensitive to the volume of lift gas injection and
that the optimum injection rate has decreased from the optimum found in Example 2 to
around 4 MMscf/day. Click | Finish and return to the | Calculation  System menu.
SEPTEMBER 2003
PROSPER MANUAL
26 - 164APPENDIX A – WORKED EXAMPLES
A3.2 Plotting the Temperature Profile
Click | Sens. PvD and use the scroll arrows to select the solution rate for 4 MMscf/day.
(around 3984 BPD liquid). Select the Manifold as First node and the Casing at 11400 ft as
the last node. Click | Continue  Calculate to compute the gradient at the solution flow rate.
The pressure profiles for the flowline and tubing can be displayed on the same or separate
plots. Click Plot  Variables and select Length (surface & down hole) on the Y-Axis and
Pressure and Temperature on the X-axis, then click | Done to plot the profiles in the tubing
as follows:
Figure A3.3:
Well Pressure and
Temperature Profiles
Note the change of slope of the pressure gradient at the depth of injection. The fluid
temperature approaches that of the surroundings about halfway along its length. The
pressure gradient in the flowline rapidly increases over its last third. This is due to high flow
velocities as ever increasing volumes of gas breaks out of solution. Increased frictional
pressure losses in the flowline account for the decrease in optimum lift gas injection rate
observed in this example.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 27 - 164
A4 Example 4 - Temperature Prediction
File: ~/samples/PROSPER/enthalpy.out
This example shows how PROSPER's Enthalpy Balance temperature model can be used to
predict the wellhead flowing temperature (WHFT) of a high pressure / high temperature oil
well.
It is planned to drill an appraisal well to test the extent of a discovery. The
objective is to flow the well for four days at a rate of 10000 STB/d provided
that the wellhead flowing temperature remains below 200 degrees F.
The objective of this example is to determine the WHFT profile versus time.
This example demonstrates how to:
•
•
•
Build a temperature prediction model for an offshore appraisal well
Predict FWHP and FWHT profiles for various rates
Generate a temperature gradient profile
A4.1 Defining the System
First start PROSPER, then select File  New to clear any existing data. Set up the
temperature prediction model by clicking Options from main menu and making the following
selections:
• Fluid type:
Oil and water
• Flow type:
Tubing
• Well type
Producer
• Separator
Single-stage
• Predicting
Pressure and temperature offshore
• Temperature model
Enthalpy balance
• Lift method
None (Naturally flowing)
• Completion
Cased hole
• Gravel pack
No
Next, enter the PVT data. Only basic PVT data from the exploration well is available. Click
PVT  Input data and enter the following:
• Solution GOR
1500 scf/STB
• Oil Gravity
45 API
• Gas Gravity
0.6 specific gravity
• Water Salinity
100000 ppm
• Mole Percent H2S
0
• Mole Percent CO2
0
• Mole Percent N2
0
Select PVT correlations known to match reservoir fluids in this region:
• Select Glaso
for Pb, GOR and FVF
• Select Beal et al
for oil viscosity
SEPTEMBER 2003
PROSPER MANUAL
28 - 164APPENDIX A – WORKED EXAMPLES
The validity of these correlations for this type of fluid behaviour has been
assumed for the purpose of this example only.
Then click | Done to return to the main menu.
A4.2 Defining the Equipment Data
The well equipment, riser, surface environment and the properties of the formations
penetrated by the well must be specified to allow PROSPER to calculate heat losses. This
necessitates significantly more data entry than for predicting pressure only applications.
Enter the well equipment details. Click System  Equipment  All  Edit and type in the
following deviation survey data:
Bottom MD (ft)
0
14000
TVD (ft)
0
14000
Next, enter the surface environment (Offshore) data:
•
•
•
•
•
•
Air temperature
Humidity
Mean sea level WRT origin
Sea bed WRT origin
Air velocity
Sea velocity
50 degrees F
60 percent
100 ft
400 ft
4 ft/sec
3 ft/sec
The user can enter a sea temperature gradient in the enthalpy balance model. We are going
to assume a linear change of temperature from the sea level (50 degree F) to seabed (42
degree F). Hence, enter the following in the Sea Temperature Gradient Table:
TVD from mean sea level (ft)
0
300
Sea temperature (degree F)
50
42
The above data describes a drilling rig with a rotary table 100 ft
above sea level located in 300 ft of water.
Define the drilling and completion by entering the drilling and completion data as shown on
the table below. This describes a well with all casing strings hung off at the sea bed and the
well is tied back to surface using a 30" riser.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 29 - 164
Figure A4.1:
Drilling and Completion
Input
Here, we are assuming that the annulus is filled with mud. The users can also customise
their own completion liquid or gas type if the appropriate fluid data is available.
Define the lithology by entering the data shown on the screen below:
Figure A4.2:
Litho logy Input
Click | Done when finish.
Then click | Cancel to enter NO surface equipment
Define the production string by entering the following:
•
•
•
•
•
•
Xmas tree
tubing type
measured depth
Inside diameter
Outside diameter
Roughness
0 ft
mild steel tubing
13600 ft
4.778"
5.5"
0.0006
Click | Summary to check the data input before returning to the main screen.
SEPTEMBER 2003
PROSPER MANUAL
30 - 164APPENDIX A – WORKED EXAMPLES
Define the reservoir inflow model by clicking System  Inflow performance. Select PI Entry
IPR and enter the following:
• Reservoir pressure
6100 psig
• Reservoir temperature
290 degrees F
• Water cut
0%
• Click on the | Input Data button and enter a PI of 8 BOPD/psi
Click | Calculate and an AOF around 28660 STB/day will be calculated. Click Main and
return to the Main menu.
A4.3 Calculation Section
The objective of the calculation is to determine whether the wellhead flowing temperature will
rise above 200 degrees F within 4 days whilst flowing at a rate of 10000 STB/d.
In order to predict the FWHT and FWHP for a given rate, the
Unconstrained System option should be used.
Sensitivities can be run using the Unconstrained System option.
•
•
In order to see the effects of rate and time on WHFP, make the following
calculations.
Generate a temperature gradient plot using the Unconstrained Gradient option.
To do this, click Unconstrained System from the main menu and make the following
selections:
•
•
•
•
•
•
Water cut
0 percent
Time since production started
1 day
Surface flow line correlation
Dukler-Flannigan
Vertical lift correlation
Hagedorn Brown
Rate type
Liquid
Enter rates of 5000, 10000 and 15000 STB/d
Click | Continue and enter the following sensitivity data:
•
For variable 1 select time since production started, and enter 1, 2, 5 and 100
days
Click | Continue and advance to the calculation screen.
Then click | Calculate to start the pressure and temperature computation.
Once the calculation is finished click | Plot. Select Tubing head temperature as the
sensitivity variable and click | Done to display the following plot.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 31 - 164
Figure A4.3:
Temperature Sensitivity
Plot
From the plot it can be seen that at 10000 STB/d the wellhead flowing temperature (WHFT)
has reached around 146 degrees F after 5 days of flowing so the design test sequence is
OK.
•
•
It also shows that the well could be flowed at up to 15000 STB/d for 100 days and the
WHFT would not reach the limiting 200 degrees F.
The calculated WHFT for 100 days production shows that high temperature well
head equipment will be required for long term production rates above 10000 stb/d.
A4.4 Generating a Temperature Gradient Plot
The Unconstrained Gradient option can be used to generate a temperature gradient for a
rate of 10000 STB/d after 5 days of flowing time. To do this, select Unconstrained Gradient
and enter the following:
•
•
•
•
•
•
•
•
•
•
First node pressure
First node fluid temperature
Water cut
Time since production started
Surface flow line correlation
Vertical lift correlation
Rate
Rate type
First node
Last node
4100 psig (this was read from the IPR)
290 degrees F
0 percent
5 days
Dukler Flannigan
Hagedorn Brown
10000 STB/d
Liquid
13 Casing at 14000 ft
1 Xmas tree at 0 ft
Click | Continue, then select Time since production started as the sensitivity variable and
enter 1,5 and 1000 days. Leave the other sensitivity variables blank. Click | Continue 
Calculate to start the calculations. Once the calculation has finished click Plot and the
following temperature gradient plot will be displayed:
SEPTEMBER 2003
PROSPER MANUAL
32 - 164APPENDIX A – WORKED EXAMPLES
Figure A4.4:
Temperature Gradients
To plot the heat transfer coefficient along the well, click | Variables  Extended and select
Heat Transfer Coefficient. Click | Done to display the following plot:
Figure A4.5:
Heat Transfer Coefficient
Plot
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 33 - 164
A5 Example 5 - ESP Lifted Well
File: ~/samples/PROSPER/espwell.out
The objectives of this example are to:
•
•
•
Determine the pump duty required to meet a specified offtake rate
Select a suitable combination of pump, motor and cable for the service
Determine the maximum water cut at which the pump can still operate with
the design offtake rate.
This example demonstrates how to:
•
•
•
•
•
Use existing PVT and VLP data as the basis of a new analysis
Calculate pump intake and outlet pressures
Design an ESP system
Evaluate pump operating point sensitivities
Calculate a flowing gradient for an ESP equipped well.
A5.1 Defining the System
From the main menu, click File  New and reinitialise the program input and output files.
Open the file OILWELL.SIN from Example 1 and make the following changes to set up an
ESP example:
•
•
•
•
Click Options and select Lift method - Electric Submersible Pump
Lower the GOR (and the well's ability to naturally flow) by clicking PVT  Input
data and lowering the GOR from 820 to 300 scf/STB
Revert to unmatched PVT correlations by clicking Correlations  Reset All.
Return to the main menu by clicking | Done twice.
Edit the System  Equipment (Tubing) description to include the annulus
dimensions as per the following input screen:
Figure A5.1:
ESP - Down hole
Equipment
SEPTEMBER
34 - 164APPENDIX A – WORKED EXAMPLES
•
•
•
•
•
Set the tubing O.D. to 4.5 inches and the casing I.D. to 6.184 inches.
Return to the main menu.
Lower the reservoir pressure by clicking on | System  Inflow performance and
setting the reservoir pressure to 4500 psig.
Change the water cut and total GOR to 80% and 300 scf/stb respectively. Leave the
other parameters at their original values.
Return to the main menu.
If not already done, initialise the ESP databases by following procedures:
Click | Design | Electrical Submersible Pump | Pump Databases | Import | Overwrite. Pick up
the file PUMPS.DAT from the \SAMPLES\PROSPER subdirectory.
•
•
•
Import the motor characteristics and the cables data in the same manner.
Note that motor files are arranged by manufacturer.
Append the individual motor files if you want to work with motors from more than one
supplier.
For designing a new ESP installation, do not enter any ESP System data - go directly to |
Design | Electrical Submersible Pump | Design and enter the following design specifications:
•
•
•
•
•
•
•
•
•
•
•
•
Pump depth
Operating frequency
Maximum OD
Length of cable
Gas separation efficiency
Design rate
Water cut
Top node pressure
Motor power safety margin
Pump wear factor
Pipe correlation
Tubing correlation
PETROLEUM EXPERTS LTD
8000 ft
60 Hz
5.7 inches
8100 ft
0 percent
6000 STB/d
80 percent
50 psig
0 percent
0 percent
Dukler Flannigan
Petroleum Experts 2 (reset
parameters if necessary)
the
match
APPENDIX A – WORKED EXAMPLES 35 - 164
A5.2 Designing the pump
Click | Calculate to display the pump duty calculation screen. Click Calculate again to find
the pump duty as per the following example:
Figure A5.2:
ESP - Design Duty
There is no free GLR at the pump intake, so a gas separator is not
required. The Sensitivity plot can be used to estimate the separator
efficiency required to reduce the intake free GLR to an acceptable level.
Click | Done and | Design and PROSPER will display the ESP Design screen.
Figure A5.3:
ESP - Pump Selection
For this example, select the REDA GN5600 pump from the list of suitable pumps. The pump
needs 115 stages and will require 215 HP at the design rate. From the list of suitable
motors, select a 240 HP REDA 540 Series 91 - Standard motor with 2210 Volt windings.
SEPTEMBER 2003
PROSPER MANUAL
36 - 164APPENDIX A – WORKED EXAMPLES
Select a #1 Copper cable. (A smaller cable would pass the current - you can select any
cable large enough for the service).
Click Plot to display the design operating point superimposed on the pump performance
curve:
Figure A5.4:
GN5600 Operating Point
The pump is being run a little close to its maximum output, perhaps the next biggest pump
would be a better choice, especially if the pump is expected to handle a greater lift duty due
to e.g. increasing water cut during the pump's run life. Return to the design screen and
select a GN7000 pump. The same 240 HP motor is suitable for this pump also. Select a #1
Copper cable and plot the results:
Figure A5.5:
GN7000 Operating Point
This pump is operating close to its optimum efficiency and has some excess head capacity.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 37 - 164
A5.3 Checking the design for different conditions.
Now, we must check whether this design will be able to cope with expected variations in the
well conditions expected to occur over the next few years. This is done using the |
Calculation section to compute sensitivities as follows:
•
•
•
•
•
Click | Main to return to the main menu
Click | Calculation  System and enter a top node pressure of 50 psi and a
water cut of 80%
Check that Dukler Flannigan has been selected for surface equipment and
Petroleum Experts 2 is selected for the vertical lift correlation
Select User Selected rates and Generate 10 rates between 10 and 10,000
BFPD.
Click | Continue and enter the following sensitivity variables:
For variable 1
−
Select Water cut
Enter 80, 90
For variable 2
−
Reservoir Pressure
Enter 4200, 4500
For variable 3
−
Select Operating Frequency
Enter 60, 65, 70
Click | Continue | Calculate to perform the sensitivity calculations.
Once the calculations have been completed, click | Solution Details, select the design case
variables of 80% water cut, 4500 psi reservoir pressure and 60 Hz operating frequency by
clicking on the variable arrows. The calculated liquid offtake rate is close to 6000 STB/day.
When the calculated rate is slightly higher than the design rate, this is to the number of
stages having being rounded up to the nearest integer.
Now, increase the water cut to 90% - the offtake rate drops to around 5480 STB/day. Plot
the sensitivities by clicking | Pump Plot from the pump solution screen as follows. From the
plot following conclusions can be made
•
With 90% water cut, can the design offtake of 6000 BFPD be achieved by increasing
the operating frequency. Select 70 Hz. The production rate increases to around
7080 BFPD. By interpolation, this pump should be capable of lifting 6000 BFPD at
an operating frequency of around 63.5 Hz.
SEPTEMBER 2003
PROSPER MANUAL
38 - 164APPENDIX A – WORKED EXAMPLES
Figure A5.6:
ESP Sensitivities
To find the required motor horsepower, return to the sensitivity screen and click on |
Combinations. Input the data shown on the following screen to set up 2 scenarios:
Figure A5.7:
ESP Combinations
Calculate the sensitivities then click | Solution Details to inspect the results for each Case.
For a 90% water cut, the GN7000 pump can lift 6035 STB/day, provided that the motor can
supply the additional horsepower at 63.5 Hz. The horsepower requirement increases from
225 to 272 HP (+21%), so a larger motor than the original selection would be required for
this service. Before finalising the design, more extensive sensitivities should be run and the
manufacturer's specifications must be checked to ensure that the specified pump can
withstand the additional shaft torque and that the housing pressure rating is not exceeded.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 39 - 164
A6 Example 6 - HSP Lifted Well
File: ~/samples/PROSPER/hspwell.out
The objectives of this example are to:
•
Select a suitable combination of pump and turbine.
This example demonstrates how to:
•
•
•
•
Use existing PVT and VLP data as the basis of a new analysis
Calculate pump intake and outlet pressures
Design an HSP system
Evaluate pump operating point sensitivities
A6.1 Defining the System
From the main menu, click File New and reinitialise the program input and output files. In
order to be consistent with the previous examples and be able to compare the requirements,
we will be using the same example. Open the file OILWELL.SIN from Example 1 and make
the following changes to set up an HSP example:
•
•
•
•
•
•
Click Options and select Lift method – Hydraulic Drive Down hole Pump
Make sure that the Artificial lift type is set to – Commingle Annular Supply
Lower the GOR (and the well's ability to naturally flow) by clicking PVT  Input
data and lowering the GOR from 820 to 300 scf/STB
Enter the Power fluid (water) salinity as 10000 ppm.
Revert to unmatched PVT correlations by clicking Correlations  Reset All.
Return to the main menu by clicking | Done twice.
Edit the System  Equipment (Tubing) description to include the annulus
dimensions as per the following input screen:
Figure A6.1:
HSP Down hole equipment
•
•
•
•
Set the tubing O.D. to 4.5 inches and the casing I.D. to 6.184 inches.
Return to the main menu.
Lower the reservoir pressure by clicking on | System  Inflow performance and
setting the reservoir pressure to 4500 psi.
Change the water cut and Total GOR to 80% and 300 scf/stb respectively.
SEPTEMBER 2003
PROSPER MANUAL
40 - 164APPENDIX A – WORKED EXAMPLES
•
Leave the other parameters at their original values and return to the main menu.
If not already done, initialise the HSP databases by following procedures:
•
•
•
•
Click | Design | Hydraulic Pump | Pump Databases | Import | Overwrite.
Pick up the file WEIRPUMPS.DAT from the \SAMPLES\PROSPER subdirectory.
Import the Turbine characteristics in the same manner.
Note that the motor files are arranged by manufacturer.
For designing a new HSP installation, do not enter any HSP System data - go directly to |
Design | Hydraulic Pump | Design and enter the following design specifications:
•
•
•
•
•
•
•
•
•
•
•
•
Pump Depth:
Pump Maximum Allowable OD:
Turbine Maximum Allowable OD:
Design (Liquid) Rate:
Water Cut:
Top Node Pressure:
Pump Speed:
Total GOR:
% Power Fluid of Reservoir Fluid:
Pump Wear Factor:
Surface Equipment Correlation:
Vertical Lift Correlation:
8000
6.1
6.1
6000
80
50
6000
300
50
0
Dukler Flannigan
Petroleum Experts 2 (clear
any correction
parameters if
applicable)
(feet)
(inches)
(inches)
(STB/day)
(percent)
(psig)
(rpm)
(scf/STB)
(percent)
(fraction)
A6.2 Designing The Pump
Click | Calculate to display the pump duty calculation screen. Click Calculate again to find
the pump duty as per the following example:
Figure A6.2:
HSP Design duty
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 41 - 164
Click | Done and | Design and PROSPER will display the HSP Design screen.
Figure A6.3:
HSP - Pump
Selection
For this example, select the Weir TP115AH(4250-12325) rpm from the list of suitable pumps.
The pump needs 69 stages and will require 233 HP at the design rate. From the list of
suitable turbines, select a weir T55-B.
Click Plot to display the design operating point superimposed on the pump performance
curve:
Figure A6.4:
Weir TP115-AH
This pump is operating close to its optimum efficiency.
SEPTEMBER 2003
PROSPER MANUAL
42 - 164APPENDIX A – WORKED EXAMPLES
A6.3 Checking the Design for Changed Conditions
Now, we must check whether this design will be able to cope with expected variations in the
well conditions expected to occur over the next few years. This is done using the | System
section to compute sensitivities as follows:
Figure A6.5:
HSP – System Calculation
•
Click | System and enter a top node pressure of 50 psi and a water cut of 80%
•
Check that Dukler Flannigan has been selected for surface equipment and
Petroleum Experts 2 is selected for the vertical lift correlation
•
Select User Selected rates and Generate 10 rates between 10 and 10,000 BFPD.
•
Click | Continue and enter the following sensitivity variables:
For variable 1
−
Select Water cut
Enter 80, 95
For variable 2
−
Reservoir Pressure
Enter 4000, 4500
For variable 3
−
Select pump speed
Enter 5000-6000-7000
Click | Continue | Calculate to perform the sensitivity calculations.
Once the calculations have been completed, click | Solution Details, select the design case
variables of 80% water cut, 4500 psi reservoir pressure and 6000 rpm pump speed by
clicking on the variable arrows. The calculated liquid offtake rate is close to 6100 STB/day.
Plot the sensitivities by clicking | Pump Plot from the pump solution screen as follows:
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 43 - 164
Figure A6.6:
HSP – Sensitivity
To find the required motor horsepower, return to the sensitivity screen and click on |
Combinations. Input the data shown on the following screen to set up 2 scenarios:
Figure A6.7:
HSP Combination
Calculate the sensitivities then click | Solution Details to inspect the results for each Case.
For 90% water cut, reservoir pressure of 4000 psig and pump speed of 7000 rpm, the
HSP pump can lift about 7000 STB/day, provided that the turbine can supply the
additional power. Before finalising the design, more extensive sensitivities should be
run and the manufacturer's specifications must be checked to ensure that the
specified HSP will work under different scenarios.
SEPTEMBER 2003
PROSPER MANUAL
44 - 164APPENDIX A – WORKED EXAMPLES
A7 Example 7 - Retrograde Condensate Well
File: ~/samples/PROSPER/condex.out ( EOS)
File: ~/samples/PROSPER/condex2.out ( BLACK OIL)
A7.1 Entering EOS PVT
A well example will be computed using the Equation of State PVT method.
The objective of this part is to show:
•
•
•
How the data input for EOS PVT works
How to calculate PVT tables and a phase envelope
Comparison of the solution results from the convergence pressure method.
To set up this problem, firstly clear the existing calculations by clicking File  New. Recall
the system data from the convergence pressure example by clicking File  Open  Analysis
(.ANL) and double clicking on the filename of the previously saved convergence pressure
example (CONDEX.ANL).
Options Menu
Select Options and ensure the following options are set:
•
•
•
•
•
•
•
•
•
PVT Method
Fluid
Separator
Flow type
Eq. of State
Well type
Predicting
Completion
Gravel pack
Equation of State
* Retrograde Condensate
Multi-Stage
Tubing flow
Peng-Robinson
Producer
Pressure only
Cased hole
No
* Defining the correct fluid at this stage is important, since calculations cannot
continue unless the EOS detected fluid type agrees with the user-selected fluid.
Click | Done, then PVT Input to display the PVT input screen:
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 45 - 164
Figure A7.1:
EOS PVT Input
•
The EOS input data is intended to be loaded from an external PVT simulation program
file using the Import button.
In case you want to use volume shift, you can enter the volume shift in the form of
S parameter and click on “ Use Vol. Shift” in the input screen shown in Figure A7.3.
To ensure that all the data has been correctly entered, and to check the type of fluid
described by the pseudo components entered.
You can do so by pressing the Phase Envelope button and hitting Calculate. The phase
envelope calculation screen shows the fluid type as shown follows:
SEPTEMBER 2003
PROSPER MANUAL
46 - 164APPENDIX A – WORKED EXAMPLES
Figure A7.2:
EOS Calculated Fluid Type
Figure A7.3:
EOS Calculated Phase
Envelope
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 47 - 164
Once the input data has been specified, the user has the option of selecting Calculation
type. The options are:
o
Calculated From EOS Model
In this option PROSPER will calculate the fluid properties from the EOS
data entered, using flash process, whenever it needs it.
o
Interpolated From Generated Tables
In this case the user generates the tables from the EOS in PROSPER
and then PROSPER during calculations, uses these tables for property
evaluation. This makes the calculations faster.
o
Interpolated From Imported Tables.
In case, the user has elected to import all the properties as a *.pvx file,
it will use the imported tables for property evaluation. THIS IS FOR
CASES WHEN THE USER DOES NOT WANT TO USE THE EOS
OF PROSPER.
For this example, we selected the first option.
In order to use the entered EOS to generate tables, enter a range of pressures and
temperatures.
Click on Generate and | Calculate again check the EOS PVT values.
The saturation pressure at 300 degrees F should be 4596 psig.
Click Properties, and PROSPER will display the equivalent Black Oil PVT
properties for the reservoir fluid as shown below:
Figure A7.4:
EOS Black Oil properties
Click Main to return to the PVT calculation screen.
A7.2 Matching Menu / Correlation Selection
Perform Correlation Comparison entering the following Data:
First node pressure : 4000 psig
Water to gas ratio:
0
Gas rate :
92 MMscf/d
Sep GOR:
7416 psig
SEPTEMBER 2003
PROSPER MANUAL
48 - 164APPENDIX A – WORKED EXAMPLES
Figure A7.5:
EOS Correlation
Comparison
The Duns and Ros Modified bottom hole pressure for the correlation
comparison case is:
•
Approx. 6972 psig, Predicted by the EOS method.
Perform | Calculation  System and use the following data
First Node Pressure 3000, 4000
Water to Gas Ratio 0 20
Tubing / Pipe diameter 4.78, 6.18
(psig)
(STB/MMscf/d)
(in)
Click | Calculate to produce a system analysis plot similar to that below:
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 49 - 164
Figure A7.6:
EOS System Solution
The calculations could take some time, so please be patient.
A7.3 BLACK OIL Condensate PVT
An identical well example as the previous one will be computed using the black oil
condensate PVT model.
The objective of this part is to show:
•
How the data input for black oil condensate PVT works
•
Comparison of the solution results from the other PVT methods.
To set up this problem, firstly clear the existing calculations by clicking File  New. Recall
the condensate example by clicking File  Open  and double clicking on the filename of the
previously saved condensate example (CONDEX.ANL).
A7.3.1 Selecting the Options
Select Options and ensure the following options are set:
•
•
•
•
•
•
•
•
PVT Method:
Fluid:
Separator
Flow type
Well type
Predicting
Completion
Gravel pack
Black Oil
Retrograde Condensate
Single - Stage
Tubing flow
Producer
Pressure only
Cased hole
No
Click | Done, then commence entry of the PVT data by clicking | PVT  Input data.
SEPTEMBER 2003
PROSPER MANUAL
APPENDIX A – WORKED EXAMPLES 51 - 164
This is in close agreement with that obtained from compositional modelling - even though the
liquid dropout values have not been matched in the Black Oil model.
Click Main to return to the main menu.
For condensate wells, the flow regime is normally mist. Prediction of slip
requires the phase volumes (hold-up) and densities. In mist flow, the slip
between liquid and gas is minimal. Even in this example the flow regime is
slug - but there is little slip between the phases for the flow rates modelled.
Provided that the mixture density is accurate, lack of precision in the
proportion of oil and gas will cause little error in pressure loss calculations.
This also explains why the main flow correlations give virtually identical
results to Fancher Brown.
For condensate wells, the black oil PVT method can be recommended for:
•
•
•
•
Accuracy of mixture density calculations
Simplicity
Speed of calculation
Accuracy of pressure calculations
Calculating the System Solution
To perform the systems analysis, click Calculation  System. Check that the calculation
setup is unchanged from the previous PVT case.
Proceed to the calculation screen and click Calculate. The solution rates are shown on the
following plot:
Figure A7.9:
Black Oil Condensate
System Solution
The above condensate example has shown how to set up the PROSPER calculations for the
different condensate PVT methods. It also illustrates that the Black Oil PVT method is
capable of accurate well pressure prediction and is more computationally efficient than more
complex PVT methods.
SEPTEMBER 2003
PROSPER MANUAL
52 - 164APPENDIX A – WORKED EXAMPLES
A8 Example 8 - Gravel Packed Gas Well
File: ~/samples/PROSPER/gravel.out
The objectives of this example are to:
• Design a gravel packed completion for a high rate gas well
• Determine the allowable offtake for a specified drawdown on the formation
This example demonstrates how to:
•
•
•
Enter the gravel pack and completion parameters
Calculate sensitivities on gravel pack and perforation variables
Calculate the pressure loss across the completion and thereby determine the
drawdown at the sand face.
A8.1 Defining the System
From the main menu, click on | File  New to reset input, analysis and output data. Set up a
new problem by making the following selections on the | Options menu:
A8.1.1 Options Menu
•
•
•
•
•
•
•
•
•
PVT Method:
Fluid:
Separator
Flow type
Well type
Predicting
Model
Completion
Gravel pack
Black Oil
Retrograde condensate
Single stage
Tubing flow
Producer
Pressure and temperature (offshore)
Rough approximation
Cased hole
Yes
A8.1.2 PVT menu
Click | Done and enter the following data on the PVT  Input screen:
•
•
•
•
•
•
•
•
•
•
•
•
Separator pressure
Separator temperature
Separator GOR
Separator gas gravity
Tank GOR
Tank gas gravity
Condensate gravity
Water to gas ratio
Water salinity
Dew point at reservoir temp.
Reservoir temperature
Reservoir pressure
1200 psig
120
deg F
25,000 scf/STB
0.7
specific gravity
1
scf/STB
0.7
specific gravity
55
API
4
bbl/MMscf
10,000 ppm
4500 psig
220
degrees F
5000 psig
Select the Lee et al gas viscosity correlation, then click | Done to return to the main menu.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 53 - 164
A8.1.3 System Menu (Equip & Inflow)
Equip Data
Click System  Equipment  All  Edit and enter the following equipment description:
•
Deviation Survey
Bottom MD
(ft)
0
10000
TVD
(ft)
0
10000
•
Enter NO surface equipment.
•
Enter the tubing string details as follows under down hole section:
Xmas tree
Tubing
SSSV
Tubing
Casing
•
Bottom MD
(ft)
0
500
9800
10000
ID
(ins)
Roughness
(ins)
3.958
3
3.958
8.681
0.0006
0.0006
0.0006
Enter the flowing temperature survey data:
Bottom MD
(ft)
0
10000
Overall heat transfer coefficient
Formation temperature
(deg F)
60
220
4.0 BTU/hr/ft2/F
Well Inflow and Gravel Pack Input
• Define the well inflow performance as follows:
•
•
•
•
•
•
IPR method:
Mechanical / Geometrical skin method
Deviation / Partial penetration skin
Reservoir pressure
Reservoir temperature
Water / Gas ratio
Petroleum Experts
Karakas & Tariq
Cinco / Martin-Bronz
5000
psig
220deg F
4 BBL/MMscf
Click on the | Input data button on the top right hand corner of the window. In the reservoir
model data entry screen, enter the following:
•
•
•
•
•
•
•
•
•
•
•
Reservoir permeability
Reservoir thickness
Drainage area
Dietz shape factor
Well bore radius
Perforation interval
Reservoir Porosity
Time
Connate water saturation
Non-Darcy coefficient
Permeability entered
SEPTEMBER 2003
300 mD
100 ft
640acres
31.6
0.51
ft
50 ft
0.2 fraction
100days
0.2 fraction
Calculated
Total permeability
PROSPER MANUAL
54 - 164APPENDIX A – WORKED EXAMPLES
Then click on the | Mech./ Geom. skin tab and enter the following:
•
•
•
•
•
•
•
•
•
Perforation diameter
Shots per foot
Perforation length
Damaged zone thickness
Damaged zone permeability
Crushed zone thickness
Crushed zone permeability
Shot phasing
Vertical permeability
0.5
6
12
12
150
0.2
75
60
30
ins
1/ft
ins
ins
mD
ins
mD
degrees
mD
Click on the | Dev/PROSPER skin tab, and enter the following:
•
•
Deviation
Penetration
0
0.5
degrees
Click on the | Gravel pack tab and define the gravel pack parameters as follows:
•
•
•
Gravel pack perm
Gravel pack length
Perforation efficiency
40000 mD
1.3
ins
1
Click | Calculate and the program will calculate an AOF of 116 MMscf/day display the IPR on
a plot. Click | Main and return to the main menu.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 55 - 164
A8.2 Sensitivity Calculation Menu
To evaluate the sensitivity of the well to completion parameters such as:
•
•
perforation density
gravel pack permeability
Click | Calculation  System.
Select Dukler Flannigan as the surface equipment correlation and Duns and Ros Modified
for the VLP correlation.
Leave the rate method set to Automatic linear and click OK.
Set the top node pressure to 1200 psig and the water/gas ratio to 4 bbl/ MMscf.
Click OK again to display the sensitivity variables screen.
To perform the design sensitivity calculations, enter the following sensitivity variables:
For variable 1
−
Select Shots per foot
Enter 4, 8, 12
For variable 2
−
Select Gravel pack permeability
Enter 10000, 40000, 80000
For variable 3
−
Select First node Pressure
Enter 1200, 2000, 3000
Click | Continue.
• Calculate to perform the system sensitivity calculations.
• Go directly to the sensitivity plot, click | Variables and select dP Completion as the Y-axis
variable, Shots per foot for the X-axis and gravel pack permeability for the parameter
variable.
• Plot the results for 1200 psi top node pressure. A graph similar to the following will be
displayed:
SEPTEMBER 2003
PROSPER MANUAL
56 - 164APPENDIX A – WORKED EXAMPLES
Figure A8.1:
Gravel Pack Sensitivity
Note that when the sand face pressure drops below the dew point, liquid
dropout occurs. The Petroleum Experts IPR reduces the relative permeability to
gas when liquids are being produced.
•
•
In this producing area, field trials and lab tests have established that gravel pack failure
should not occur provided that the total pressure drop across the completion is less than
400 psi (for purposes of illustration only)
By inspection, the above sensitivity plot shows that 12 shots per foot perforations and a
gravel pack permeability of 40 Darcies will be required to ensure that the well will not
have to be choked back unnecessarily.
Return to the calculation screen and click on | Solution Detail, then select the solution for
•
12 SPF, 40000 mD and 1200 psi.
From the solution summary, we know that the pressure drop across the completion is almost
all due to the gravel pack. In excess of 85 MMscf/day can be safely produced with this
completion design.
To determine the allowable rate
•
if the well had been perforated at 8 SPF
Make a sensitivity plot with dP completion on the Y-axis, First node pressure on the X-axis
and Gravel Pack Permeability as the parameter variable.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 57 - 164
Figure A8.2:
Gravel Pack Sensitivity
Assume that the gravel pack has 40000 mD permeability. Zoom on curve 1 (8 SPF) near
where it is around 400 psi dP completion and read off the First Node Pressure. You should
get around 2500 psi.
Click | Finish and | Done to display the Select variables screen.
To calculate the gas production rate for 400 psi dP completion, use the Combinations option
on the Select variables screen. Enter the following for combination Case 1:
•
•
•
Shots per foot
Gravel pack permeability
First node pressure
8 1/ft
40000 mD
2500 psig
Leave the rate field blank. Click | Continue and then | Calculate. PROSPER will calculate the
system solution. Click | Solution details and check that the well can flow at 63 MMscf/day
with a THP of 2500 and a dP across the completion of 410 psi. Note that the allowable rate
at 8 shots per foot is more than 20 MMscf/day lower than the allowable with 12 shots per
foot.
SEPTEMBER 2003
PROSPER MANUAL
58 - 164APPENDIX A – WORKED EXAMPLES
A8.2.1 IPR Liquid Sensitivity
To evaluate the effect of increased liquid production on IPR and production rates, click Main
to return to the main menu. Click Calculation  System. Leave the input parameters as for
the preceding runs. Click | Continue | Variables and clear the existing sensitivity variable
entries. Next, enter the following sensitivity data for variable 1 only:
−
Select Separator GOR
Enter 2000, 5000, 25000 scf/STB
Click | Continue to continue to the calculation screen. Click | Calculate and calculate the
sensitivities. Click Plot  Variables and select IPR, VLP and dP skin completion for Yvariable, and choose all three separator GOR, then click | Done to display the following:
Figure A8.3:
IPR liquid sensitivity
Note the effect of Separator GOR on both VLP and IPR pressures. Note that increasing
liquid production increases the completion dP.
Click | Main to return to the main menu. Save the file as GRAVEL.ANL if desired.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 59 - 164
A9 Example 9 - Horizontal Well - Friction dP
File: ~/samples/PROSPER/hwell.out
The example shows how to set up the input data for a Horizontal well - Friction dP IPR
model. It is based on the OILWELL example file.
•
Note that the reservoir permeability must be increased from 50 in the base example to
500 millidarcies in order to see the friction pressures drop along the well bore.
A9.1 Setting up the example
From the main menu, click File  New to reset input, analysis and output data. Click File 
Open and select OILWELL.ANL from the SAMPLES sub-directory. This will avoid the need
to enter down hole equipment or PVT data.
A9.1.1 IPR Data Input
Click System Inflow Performance and enter the following:
IPR Method
Reservoir Pressure
Reservoir Temperature
Water Cut
Horizontal Well - dP Friction loss
5,000 psig
210
deg F
0
percent
Click on the | Input data button, and enter the following data for the reservoir and horizontal
well.
Horizontal Well Model
Reservoir Permeability
Reservoir Thickness
Horizontal Anisotropy
Vertical Anisotropy
Well Length
Reservoir Length
Reservoir Width
Length distance to reservoir edge
Width distance to reservoir edge
Bottom of reservoir to well centre
Kuchuk and Goode
500
mD
200
feet
1
fraction
0.2
fraction
1,000 feet
10,000 feet
5,000 feet
2,000 feet
1,000 feet
100
feet
Next, set up the well completion details i.e. zone data.
•
•
•
•
This well has alternating perforated and blank sections, which are identical.
We will enter the data for two only two zones, one blank one producing.
Then we will use the editing features to copy identical data to the other zones.
For the first zone enter the following:
Zone Type
Skin Method
Gravel Pack
Zone Length
Zone Permeability
SEPTEMBER 2003
Perforated
By Hand
This will be automatically skipped
100
feet
500
mD
PROSPER MANUAL
60 - 164APPENDIX A – WORKED EXAMPLES
Flowing Radius
Zone Roughness
0.15
0.001
feet
inches
Click the Zone Data button and enter the following:
•
•
•
Skin
Well bore Radius
Click | Done
Enter the following for the second Zone:
Zone Type
Zone Length
Flowing Radius
Zone Roughness
•
2
0.354
Blank
100
feet
0.15 feet
0.001 inches
Copy the data for Zone 1 (perforated) and 2 (blank) to other layers as follows:
•
•
•
•
Select the layers by clicking the select button to the left of the screen for Zone 1.
Hold down the Control key and select Zone 2 also.
Click Copy to copy the elected layers into memory.
Click the select button for Zone 3, then Paste to transfer Zone 1 and 2 data to
zones 3 and 4.
• Select Zone 5 and repeat the Paste process.
• Work through to Zone 9 to complete the data input for all 10 zones.
Figure A9.1:
Horizontal well - dP
Friction IPR input
A9.2 Coning Calculations for Horizontal Wells
PROSPER has some Steady-State gas / water coning models ij10Scs000910.98 131.0405 165.12 0 Pe7
APPENDIX A – WORKED EXAMPLES 61 - 164
Rate
Reservoir Porosity
Coning Calculation
40,000 STB/day
0.2
fraction
Water Coning
All the IPR input must have been defined before performing the coning
calculations.
Click | Calculate, and the breakthrough time and critical rate estimates will be displayed.
Figure A9.2:
Horizontal well – Coning
Calculations Screen
To calculate and display the horizontal well pressure profile and production contribution from
each zone for the entered rate, click Plot. PROSPER will display a graph similar to the
following:
Figure A9.3:
Horizontal well - dP
Friction Well pressure
profile
The source of inflow can be plotted by clicking Variables and selecting Rate per Unit Length.
As shown in the following plot, more production enters at the heel of the well than the toe:
SEPTEMBER 2003
PROSPER MANUAL
62 - 164APPENDIX A – WORKED EXAMPLES
Figure A9.4:
Horizontal well - Rate per
Unit Length
Click | Finish | Done to return to the IPR calculation screen.
When you click | Calculate from this screen, PROSPER calculates the entire IPR curve and
finds the AOF. Click | Main, and you are returned to the main PROSPER screen without
carrying out the potentially time consuming AOF calculation.
Once the Horizontal well dP friction IPR, has been calculated, System calculations can be
carried out as normal. If you need to calculate a wide range of sensitivity cases, the dP
friction model could be used to prepare a table of test data points to be entered in one of the
fast-calculating multi-rate IPR models.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 63 - 164
A10 Example 10 - Multi-Layer dP Pressure Loss
File: ~/samples/PROSPER/mlayer.out
The example shows how to set up the input data for a Multi-Layer IPR model. It is based on the
OILWELL example file.
A10.1
•
•
•
Setting up the example
From the main menu, click FileNew to reset inputs, analysis and output data.
Click File  Open  Input and Analysis and select OILWELL.ANL from the SAMPLES
sub-directory.
This will avoid the need to enter down hole equipment or PVT data.
A10.2
IPR Data Input
Click System  Inflow Performance and enter the following:
IPR Method
Reservoir Temperature
Relative Permeability
Multi-layer - dP loss
210
deg F
No
Click on | Input data, and the layer data entry screen will be displayed.
Figure A10.1:
Multi-Layer data Input
The following description shows how to set up a well model with two layers separated by 100
feet.
SEPTEMBER 2003
PROSPER MANUAL
64 - 164APPENDIX A – WORKED EXAMPLES
A10.2.1
STEP1: Defining the top of the multi-layer system
Enter the location of the top of the producing zone - measured depth 11,400, TVD 10,430.
This is the deepest depth in the deviation survey table.
A10.2.2
STEP2: Defining the to Top Producing layer
Enter the following data for Layer 1 (Top Producing Zone):
Layer type
Layer IPR model
Layer skin model
Measured depth
True vertical depth
Layer pressure
Layer flowing radius
Layer roughness
Perforated
Darcy
By hand
11,500 feet
10,500 feet
5000 psig
0.25 feet
0.001 inches
Click the Layer PVT data button and enter the following:
Layer formation GOR
Layer oil gravity
Layer gas gravity
Layer water cut
820
34
0.7
0
scf/STB
API
s.g.
percent
Click | Done.
Click on Layer model data button and enter the following:
Layer permeability
Layer drainage area
Layer Dietz shape factor
Layer well bore radius
100
mD
640
acres
31.6
0.354 feet
Click | Done.
Click on Layer skin data button and enter a skin of 2.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 65 - 164
A10.2.3
STEP3: Defining the non producing zone
Layer 2 is the section of blank pipe that separates the two producing layers. Enter the
following for Layer 2.
Layer type
Measured depth
True vertical depth
Layer flowing radius
Layer roughness
A10.2.4
Blank
11,600 feet
10,600 feet
0.25 feet
0.0006 inches
STEP4: Defining the to Bottom Producing layer
Enter the following for Layer 3:
Layer type
Layer IPR model
Measured depth
True vertical depth
Layer pressure
Layer flowing radius
Layer roughness
Perforated
P.I. Entry
11,700 feet
10,700 feet
4800 psig
0.25 feet
0.001 inches
Click the | Layer PVT data button and enter the following:
Layer formation GOR
Layer oil gravity
Layer gas gravity
Layer water cut
820
34
0.7
30
scf/STB
API
s.g.
percent
Click | Done.
Click Layer model data button and enter
PI
5.
Click | Done | Calculate and PROSPER will calculate the composite IPR at the intake node.
The IPR plot shows the layer contributions and the combined IPR as in the following
example:
SEPTEMBER 2003
PROSPER MANUAL
66 - 164APPENDIX A – WORKED EXAMPLES
Figure A10.2:
Multi-layer dP pressure
loss
Click Results to see the layer pressures and production contributions. Crossflow into a layer
appears as a negative production value as in the following example:
Figure A10.3:
Multi-layer dP pressure
loss Results Screen
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 67 - 164
A11 Example 11 – Multilateral well
File: ~/samples/PROSPER/multilat1.out
A11.1
Introduction
Multi-lateral wells are being recognized as a potential option when developing new oil and
gas fields. Often, these type of wells are drilled to save the costs of drilling, this may occur if
drilling individual targets is sub - economic or the platform is constrained. Sometimes they
are not beneficial.
Co-mingling the flow from two targets (branches) may result in higher outflow performance in
the event that a larger tubing size can be specified; this leads to a lower frictional pressure
drop than in obtained in each individual well. But sometimes, co-mingling fluids may result in
greater frictional pressure drop than expected, so poorer outflow performance than two
individual wells will result, it means that well productivity depends on interference effects in
both reservoir and well bore. Cross flow might represent another potential problem if targets
for several branches are chosen without any proper study.
This is where modelling work can add most of the value: multilateral wells are different to
single wells because they have a variable structure. Both the number of branches and the
way that they are connected is variable, and also the interaction between each branch
should be taken in to account. Hence, a flexible way to model must be used to understand
the behaviour of this type of wells.
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A11.2
How to set up the model
The objectives of this example are to:
•
•
Go through the step by step procedure for defining a multi-lateral well
Consider the situation in which a high angle multilateral side track that will target
a thin zone in a fault block has to be drilled but an investigation of the of the increase of
oil and interference has to be analysed first as well as the productivity index.
This example can be found in the samples directory under the name of MULTILAT1.OUT
file. However, following the steps indicated below, you would be able to generate the model
from scratch.
Figure A11.1:
Well Sketch that displays
the drilling program
The multilateral data entry screen is accessed by choosing | System | Inflow Performance
from the PROSPER main menu, as with the single well IPR.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 69 - 164
Figure A11.2:
System Summary
Inflow type: Multilateral
1. Begin by starting the program. From the PROSPER main menu, select File  New to
reinitialise the program input and output files. The ‘New’ menu item under File is only
available if a file has already been loaded. If there is no file loaded skip this step
and go to next step.
2. To begin setting up the system options, select Options Options or double-click on the
‘SUMMARY DATA’ area and make the following selections:
•
•
•
•
•
•
•
•
•
•
•
•
Fluid:
Oil and Water
Method:
Black Oil
Separator: Single-Stage Separator
Flow type: Tubing Flow
Well type:
Producer
Predict:
Pressure and Temperature (Offshore)
Model:
Rough Approximation
Range:
Full System
Output:
Show Calculating Data
Type:
Cased Hole
Gravel pack:
No
Reservoir: Multi-Lateral well.
Then click Done to exit this screen. This completes the system setup and reinitialises the
program and governs the inputs that the user will be required to enter.
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70 - 164APPENDIX A – WORKED EXAMPLES
Entering the PVT data
3. In this section we will enter the PVT input data required.
4. Select the PVT menu in the main screen:
•
Click Input data
or
•
Double-click on the ‘PVT DATA’ area of the main screen and enter the following:
Solution GOR:
Oil Gravity:
Gas Gravity
Water Salinity
Mole Percent H2S:
Mole Percent CO2:
Mole Percent N2:
752
scf/stb
32
API
0.67
150000 ppm
0%
0%
0%
Figure A11.3:
PVT Input Screen
Click Done on the above screen to exit. This marks the end of defining the PVT behaviour
Entering the Equipment data
5. The next task is to define the well bore itself and surface lines (if any). This is done in the
following steps.
•
Click System  Equipment (Tubing etc) on the main PROSPER screen
or
•
Double-click on the ‘EQUIPMENT DATA’ area
6. Then click All  Edit
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 71 - 164
The program will automatically lead you through the required equipment data screens
starting with the well deviation survey. Enter the following into the deviation survey data
table:
Measured
Depth
(feet)
0
9700
True Vertical
Depth
(feet)
0
8800
While entering the deviation survey, PROSPER calculates automatically the cumulative
displacement and the angle of the well.
•
•
•
•
•
Click Done to continue to the surface equipment screen
Click Cancel to enter NO surface flow line data
The down-hole equipment screen will then appear. Enter the data in the screen
as follows
The well has 4.67" ID tubing down to 13000 ft, which is the tie point.
Click on the Type cells to get a combo box of options and enter the following
down hole equipment:
Type
Xmas tree
Tubing
Measured
Depth
(feet)
0
9700
IDs
Roughness
(ins)
(ins)
4.67
0.0006
Figure A11.4:
Equipment
Input Screen
• Click Done to advance to the geothermal data entry screen. Once on the screen, enter
the following temperature profile:
Measured
Depth
(feet)
0
SEPTEMBER 2003
Formation
Temperature
(deg F)
60
PROSPER MANUAL
72 - 164APPENDIX A – WORKED EXAMPLES
9700
200
Enter an overall heat transfer coefficient of 8 Btu/hr/ft2/F. Click | Done to exit the screen.
• This takes you to the default heat capacity screen. Let it remain as it is. Click on Done to
go to the next screen.
Figure A11.5:
Geothermal Gradient
This completes the equipment input for the well.
When satisfied that the well equipment is correct, click Main to return to the PROSPER main
Notes about Equipment Data Entry Screens
i)
Make sure that the measured depth of last piece of equipment in
the downhole equipment is the same as the last depth in
geothermal gradient.
ii)
All measured depths in the downhole equipment are converted to
true vertical depths as per the deviation survey entered. Thus the
deepest point of the deviation survey should be at least as deep as
last point of equipment/ geothermal gradient.
iii)
The geothermal gradient should have a temperature entry
corresponding to depth of wellhead.
iv)
If you have a pipeline in the system, the upstream end of the
pipeline should tally with wellhead depth.
Available data for the Top and bottom layer
Top layer:
Reservoir Pressure 3900
Reservoir Temperature
Oil Gravity
Gas Gravity
Water Salinity
Water Cut
PETROLEUM EXPERTS LTD
psig
218
degrees F
34
API
0.67 sp. Gravity
120000
ppm
56
percent
APPENDIX A – WORKED EXAMPLES 73 - 164
Total GOR
Horizontal Permeability
Formation Thickness
Drainage Area
Depth of Reservoir Top
Vertical Permeability 10
Bottom Layer:
Reservoir Pressure 3200
Reservoir Temperature
Oil Gravity
Gas Gravity
Water Salinity
Water Cut
Total GOR
Horizontal Permeability
Formation Thickness
Drainage Area
Depth of Reservoir Top
Vertical Permeability 10
720
10
150
150
8770
md
scf/STB
md
feet
acres
feet
psig
210
degrees F
34
API
0.67 sp. gravity
120000
ppm
56
percent
720
scf/STB
10
md
100
feet
175
acres
8950 feet
md
According to the drilling program, the tie point will be considered at measured depth of 9700
ft m (8800 ft vertical depth). The deviation survey of the original well and the side track are
indicated below.
Completion 1
Measured
Depth
feet
9850
11473
11550
11650
11750
11759
13550
13900
Vertical
depth
feet
8920
8968
8969
8971
8974
8974
9013
9020
Azimuth
Vertical
Depth
feet
8920
8770
Azimuth
degrees
0
347
332
313
294
292
292
292
Side track
Measured
Depth
feet
9850
10700
degrees
0
327
The user interface consists of a framework window that contains several child windows, as
well as the menu and toolbar from which commands are issued. The child windows include
the network windows that contain the system network drawing, the navigator window that
can assist in the viewing of large networks and up to three visualisation windows, which can
show the multilateral network drawn to scale from three orthogonal points of view.
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74 - 164APPENDIX A – WORKED EXAMPLES
Figure A11.6:
PROSPER
Multilateral
Network
To start drawing your multilateral system considering the well sketch, start selecting the tie
point, junction, completion (1) and Completion (side track) as well as the top and bottom
reservoir.
Figure A11.7:
Adding the
completion and
reservoirs
Once you have the basic drawing according to your well sketch and drilling program, then
you can use the button (add link) to finish with this part.
To enter the required data for each section all you have to do is to double click on each icon.
It is recommended to start from the tie point to the reservoir according to the well sketch.
A Note about Tie Point
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 75 - 164
The tie point defined, is the point above which everything will be a part of
wellbore sketch and thus the pressure loss etc in that section will be a part of
VLP. Everything below the tie point is a part of the IPR and pressure losses in
this section will be evaluated in IPR calculations.
Figure A11.8:
Linking the tie
point with the joint,
completion and
reservoir.
If you double click on the tie point enter the measured depth and true vertical depth as
indicated previously. The tie point is the node where the IPR is solved and is located at the
top of the system (in vertical depth). Hence, the tie-point can only be a start point.
The Junction point will be a branching node. It can only have one link into it (from a tie-point
or a completion).
Once these two points have been defined, then, Deviation Survey and Down hole Equipment
and Perforation Details can be entered. In the case of the deviation survey there is an
additional azimuth entry.
When the user put the information respectively for each branch the calculations can be
performed.
Tie point:
Measured depth of 9700 ft m, 8800 ft vertical depth
Junction 1:
The tubing information entry is a two-step process. First we define the model for pressure
loss calculations. We will also be using the following model:
Horizontal Flow Model:
Vertical Flow Model:
Choke Model:
Flow Type:
Correlation Threshold:
Threshold Angle:
Well Bore radius:
Beggs and Brill
Petroleum Experts 2
ELF
Tubing
No
45 Degrees
0.43 feet
The screens for entering the tubing flow model are as shown below:
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Figure A11.9:
Tubing Model Selection
screen
Once the model is entered, if on the above screen you Press the Input Data button, it takes
you to the next screen where you enter the deviation survey of this path of the completion
including the azimuth.
Measured
Depth
(feet)
9700
9850
True Vertical
Depth
(feet)
8800
8920
Azimuth
0
0
Figure A11.10:
Tubing deviation survey
Input Screen
Once the deviation survey is entered, we will need to enter the equipment information like
the tubing diameters etc, in the next screen. This screen is accessed by clicking on the TAB
called EQUIPMENT in the bottom left hand corner of the screen shown above.
Tubing
Type
Start
PETROLEUM EXPERTS LTD
Measured
Depth
(feet)
9700
IDs
Roughness
(ins)
(ins)
APPENDIX A – WORKED EXAMPLES 77 - 164
Tubing
9850
4.67
0.0006
Figure A11.11:
Tubing description Input
Screen
This finishes the entry of tubing information.
Completion 1
Double click on completion 1 to enter the input data.
Select the information required such as vertical flow model, well bore radius, and Dietz
shape factor.
For this example the Petroleum Experts 2 correlation will be used, a well bore radius of 0.43 ft
and Dietz shape factor of 30 will be considered.
Figure A11.12
Completion 1,
Calculation options
screen.
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78 - 164APPENDIX A – WORKED EXAMPLES
When your press the option Input Data, you will see that there are three tabbed dialogs in
this data input screen, which allow the entry of a deviation survey, equipment descriptions
and completion information. The first two dialogs contain tables very similar to the ones
encountered by selecting System | Equipment from the PROSPER main menu, and then the
‘Deviation Survey’ and ‘Down hole Equipment’ push buttons. In the case of the deviation
survey there is an additional azimuth entry.
Enter first the deviation survey:
Figure A11.13
Completion 1
Deviation Survey
Screen
Once you enter the deviation survey, select the equipment and select tubing according to
the deviation survey, the tubing in the completion 1 has been run down to 13900 ft and has
a diameter of 3 in.
Figure A11.14
Completion 1
Equipment
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 79 - 164
According to the drilling program, this completion has been perforated between 11855 ft and
13900 ft.
Figure A11.15
Completion 1
Perforation details
Finally double click on the reservoir and enter the PVT data as well as the information
required to calculate the inflow performance based on the Darcy Model.
The information has been provided at the beginning of this example.
Figure A11.16
Bottom Reservoir
PVT Data
Press Input to continue and enter the information for the reservoir.
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80 - 164APPENDIX A – WORKED EXAMPLES
Figure A11.17
Bottom Reservoir
Inflow data
based on
Darcy Reservoir
Model
Once finished with the first completion, you can go on entering the correspondent
information for the multilateral section. So just double click on the side track completion.
Select the information required such as vertical flow model, well bore radius, and Dietz
shape factor.
In this case the Petroleum Experts 2 correlation will be used, a well bore radius of 0.43 ft and
Dietz shape factor of 30 will be considered.
Figure A11.18
Sidetrack
Input Data
Select input data and enter first the deviation survey.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 81 - 164
Figure A11.19
Sidetrack
Deviation Survey
Once you enter the deviation survey, select the equipment and select tubing, according to
the deviation survey, the tubing in the side track has been run down to 10700 ft and has a
diameter of 3 in.
Figure A11.20
Sidetrack
Equipment
According to the drilling program, this completion has been perforated for 700 ft, from 10000
ft to 10700 ft.
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PROSPER MANUAL
82 - 164APPENDIX A – WORKED EXAMPLES
Figure A11.21
Side Track
Perforation
details
Finally double click on the reservoir and enter the PVT data, as well as the information
required to calculate the inflow performance based on the Darcy Model.
The information has been provided at the beginning of this example.
Figure A11.22
Top Layer
PVT Data
Press Input Data to continue and enter the information for the reservoir.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 83 - 164
Figure A11.23
Top Layer
Inflow data based
on
Darcy Reservoir
Model
Once entered the information for the two branches (completion 1 and side track), from
PROSPER – Multilateral Network Menu, select the option Visualise all:
Figure A11.24
Visualise All
From PROSPER – Multilateral Network Menu, select the option Analyse/Calculate
The Calculate screen gives the option of calculating one IPR point or a curve.
Also, calculations can be switched between infinite and finite conductivity modes of
calculation. In the latter case (finite) the pressure drop in the tubing is taken into account
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84 - 164APPENDIX A – WORKED EXAMPLES
Figure A11.25
Calculate
The Finite conductivity solution takes in account the pressure drop and interference, whilst
the Infinite conductivity considers equal pressure and constant production rate at all times.
The flow distribution is used then to calculate the pressure around the source.
The pressure of the reservoir approaches to a constant value, then if in one particular branch
in the reservoir is surrounded by a constant pressure boundary, the pressure in the well
and the boundary will become constant (steady state pressure), when the steady state
pressure is normalized respect to the flow rate, it provides a measure of the pressure drawdown required to flow a unit of volume per unit time.
The Details button is used to display pressure and rate-related parameters with respect to
the measured and vertical tubing depths of each branch. If a curve has been calculated,
these details pertain to the last point in the curve.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 85 - 164
Figure A11.26
Details
To visualise the results press Plot, and from the menu toolbar select Variables.
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86 - 164APPENDIX A – WORKED EXAMPLES
Figure A11.27
Plot results
True Vertical
Depth vs. Rate per
unit length and
pressure
Figure A11.28
Results
Considering Infinite
conductivity
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 87 - 164
Figure A11.29
Results
Considering
Finite
Conductivity
References:
1.- SPE 5589
Pseudo Skin Factors for Partially Penetrating Directionally drilled Wells
Heber Cinco Ley & H.J. Ramey
2.- SPE 3818
The use of source and Green’s Functions in Solving Unsteady flow Problems in Reservoirs
Gringarten
3.- Fluid Flow in porous media
By Muskat
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88 - 164APPENDIX A – WORKED EXAMPLES
A12 Example 12 – Modelling of a smart well completion using
Multilateral option in PROSPER
File: ~/samples/PROSPER/multilat2.out
The objectives of this example are to:
•
Show how a complex smart well completion can be modelled by using the
multilateral option in PROSPER
Show how different tubing sizes can affect the IPR curve
•
A12.1
Statement of the problem
The smart well completion that we are going to model has the following structure.
Production packer
Quantum packer
Diverted flow
50 ft
150 ft
100 ft
100 ft
100 ft
100 ft
100 ft
ID=6.969”
ID=4.778”
5 ½” tubing
•
•
•
•
•
3 3/8” tubing
(ID=2.041”)
The horizontal completion consists of concentric casing and tubing.
The reservoir fluid is flowing into an annular space between the casing and the tubing
through the perforation segments along the casing.
The fluid is flowing in a direction away from the tie point; let us call this direction positive
x.
The total fluid then flows into tubing where their direction of flow is changed to the
negative x direction.
The tie point of the completion is located at a true vertical depth of 10,000 ft below the
wellhead.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 89 - 164
A12.2
Defining the System
Begin by starting the program. From the PROSPER main menu, select File  New to
reinitialise the program input and output files. The ‘New’ menu item under File is only
available if a file has already been loaded.
To begin setting up the system options, select Options Options or double-click on the
‘SUMMARY DATA’ area and make the following selections:
•
•
•
•
•
•
•
•
•
•
•
•
•
•
Fluid:
PVT Method:
Separator:
Flow type:
Emulsions:
Well type:
Lift method:
Predictin :
Model:
Calculation range:
Display:
Completion:
Gravel pack:
Reservoir inflow type:
Oil and Water
Black Oil
Single-Stage Separator
Tubing Flow
No
Producer
Naturally Flowing Well
Pressure and temperature (Offshore)
Rough approximation
Full System
Show calculating data
Cased Hole
No
Multilateral Well
Figure A12.1:
System Summary
Then click Done to exit this screen.
SEPTEMBER 2003
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90 - 164APPENDIX A – WORKED EXAMPLES
A12.3
Entering PVT Data
The purpose of this section is to define the fluid in the system. The fluid properties enter is
assumed to be correct and no matching will be done.
•
•
Select the PVT menu
Click Input data
or
•
Double-click on the ‘PVT DATA’ area and enter the following:
Solution GOR:
Oil Gravity:
Gas Gravity:
Water Salinity:
Mole Percent H2S:
Mole Percent CO2:
Mole Percent N2:
Correlation for Pb, Rs and Bo
Correlation for oil viscosity
500 scf/STB
39 API
0.78 specific gravity
100000 ppm
0%
0%
0%
Glaso
Beal et al
The solution GOR is the gas dissolved in the oil at the original bubble point
pressure. If the well also produces free gas, it should not be included here.
Figure A12.2:
PVT input screen
Click Done to return to main. This completes the PVT input section.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 91 - 164
A12.4
Entering the Equipment data
The next task is to define the down hole and surface equipment. Enter the well equipment as
follows:
Click System  Equipment (Tubing etc)
•
or
•
Double-click on the ‘EQUIPMENT DATA’ area
•
Then click All  Edit
The program will automatically lead you through the required equipment data screens
starting with the well deviation survey. We will assume the well is vertical and the deepest
point is at a TVD of 10,000 ft, corresponding to the depth of the tie point of the completion.
Enter the following into the deviation survey data table:
Measured
Depth
(feet)
0
10000
True Vertical
Depth
(feet)
0
10000
Figure A12.3:
Deviation survey
•
•
•
Click Plot to plot the well profile
Click Finish  Done to continue to the surface equipment screen
Click Cancel to enter NO surface flow line data
The down hole equipment screen will then appear. Note that the Xmas tree elevation has
been taken to be the same as the deviation survey reference.
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92 - 164APPENDIX A – WORKED EXAMPLES
The well has 4.778" ID tubing down to 10,000 ft. Click on the Type cells to get a combo box
of options and enter the following down hole equipment:
Type
Xmas tree
Tubing
SSSV
Tubing
Measured
Depth
(feet)
0
1000
10000
IDs
Roughness
(ins)
(ins)
4.778
4
4.778
0.0006
0.0006
Descriptive information about the downhole equipment can be written in the label fields as
reminder.
Figure A12.4:
Down hole equipment
Click Done to advance to the flowing temperature profile screen and enter the following:
Measured
Depth
(feet)
0
10000
Fluid
Temperature
(deg F)
60
250
Overall heat transfer coefficient:
PETROLEUM EXPERTS LTD
8 BTU/hr/ft2/F
APPENDIX A – WORKED EXAMPLES 93 - 164
Figure A12.5:
Geothermal gradient
Click | Done.
The Average Heat Capacities screen will then appear. Click Done to accept the default
value.
This completes the equipment input for the well.
Click Summary and check that the equipment input data is consistent. As a further check
click Draw Down hole. When satisfied that the well equipment is correct, click Main to return
to the PROSPER main screen (status screen).
A12.5
Modelling the smart well completion (IPR)
The next task is to construct a model for the smart well completion using the multilateral
option in PROSPER. It is assumed that the user has gone through some dexterity exercises
on multilateral IPR modelling. Such exercises can be found from the PROSPER online
manual, section 7.8. A more fundamental multilateral IPR example is also presented in the
previous section of the tutorial. It is recommended that the user go through those dexterity
exercises before following this example. To start,
•
Click System  Inflow performance
or
•
Double-click on the ‘IPR DATA’ area
A multilateral network construction window will appear, which looks like the figure display
below:
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94 - 164APPENDIX A – WORKED EXAMPLES
Figure A12.6:
Multilateral network
construction window
From the diagram of the completion, in terms of the flow connection, the completion can be
simplified as below
Tubing
flow
Annular flow,
Fluid flowing in
from reservoir
As can be seen, the flow network is consisted of two sections, the first section consists of
annular flow with fluid flowing in from the reservoir and the second section consists of tubing
flow.
The complexity is that the two sections are actually concentric. However,
despite the complexity, this can be modelled in PROSPER.
Two completions can be set up, with one connected to the other, representing the flowing
sections mentioned in the previous paragraph.
The user can introduce the tie point, junctions, completions and reservoir and their
connection into the network from the tool bar in the multilateral network window.
Figure A12.7:
Tool bar from the
multilateral network
window
For this particular smart well completion, a flow network can be constructed as shown below
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 95 - 164
Figure A12.8:
Construction of the flow
network
The tie point represents the end of the downhole equipment that is specified in the | System |
Equipment section. The item labelled T1 represents the 5 ½” tubing that is shown in the
smart well completion structure. The item (a completion) labelled Tubing represents the
section where tubing flow occurs. Junction1 connects the 5 ½” tubing and the tubing flow
section. The item (a completion) labelled Annular represents the section where annular flow
occurs. The reservoir is connected to the Annular. Fluid is flowing from the reservoir to the
Annular, then to the Tubing via Junction2, then to the tie point via Junction1 and T1.
After constructing the general network diagrammatically, the next step will be to describe the
network items. We start from the tie point by double-clicking on the item on the network
window. A network item data entry screen for the tie point will be displayed.
Figure A12.9:
Tie point data entry
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96 - 164APPENDIX A – WORKED EXAMPLES
Since we have a vertical well and the TVD for the tie point is at 10,000 ft, the measured
depth of the tie point is at 10,000 ft as well. Hence, enter the following data for the tie point
position:
•
•
Measured Depth:
True Vertical Depth:
10000 ft
10000 ft
Next, we are going to specify the data for item T1. To bring up the data entry screen for item
T1, simply click on the item on the equipment screen on the right. The following screen will
be seen:
Figure A12.10:
Tubing T1 data entry
screen
Enter the following data:
•
•
•
•
•
•
•
Horizontal Flow Model:
Vertical Flow Model:
Choke Model:
Flow Type:
Use Threshold Angle:
Threshold Angle:
Well bore Radius:
Beggs and Brill
Petroleum Experts 2
ELF
Tubing Flow
No
45 degree
0.7083
This only specifies the general model of tubing T1. More information is needed, e.g. the
deviation, the tubing length and diameter, etc. These data can be entered in the Input Data
section by clicking on the Input Data button on the top right hand corner of the screen.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 97 - 164
Figure A12.11:
Tubing T1 data entry
screen
We first describe the deviation. Since the smart well completion is perfectly horizontal, the
true vertical depth remains at 10000 ft. This section of the tubing is 50 ft long. Hence, the
measured depth should be 10050 ft. We assume that this section of the well is extending in
the direction of positive x, hence, the azimuth is 0 degree. In short, enter the following data
in this screen:
Measured depth
Feet
10000
10050
True Vertical Depth
Feet
10000
10000
Azimuth
Degree
0
0
Next, we proceed on to specify the tubing length, diameter, etc. These data can be entered
in the Equipment section, by clicking the tab labelled ‘Equipment’.
Figure A12.12:
Tubing T1 data entry
screen
This section of the tubing has an internal diameter of 4.778” for its whole length of 50 ft.
Hence, input the following data:
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PROSPER MANUAL
98 - 164APPENDIX A – WORKED EXAMPLES
Tubing Type
Start
Tubing
Measured Depth
Feet
10000
10050
Tubing ID
Inches
Tubing inside roughness
Inches
Rate multiplier
4.778
0.0006
1
This completes the definition for tubing T1. Next, we proceed on to Junction1. The position
of Junction1 is totally dependent on the specification of the items upstream. It’s position, i.e.
measured and true vertical depths are calculated. To see the calculated position, simply click
on Junction1 on the equipment window on the right.
Figure A12.13:
Junction1 data entry
screen
Next we proceed on to specify the completion labelled tubing. We first specify the general
model of the completion:
Figure A12.14:
Completion data entry
screen – Tubing flow
Enter the following data:
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES 99 - 164
•
•
•
•
•
•
•
•
Horizontal Flow Model:
Vertical Flow Model:
Choke Model:
Flow Type:
Use Threshold Angle:
Threshold Angle:
Well bore Radius:
Dietz Shape Factor:
Beggs and Brill
Petroleum Experts 2
ELF
Tubing Flow
No
45 degree
0.7083
31.6
To enter the deviation, the tubing length and diameter, etc. Click on the Input Data button on
the top right hand corner of the screen.
Figure A12.15:
Completion data entry
screen – Tubing flow
We first describe the deviation. Since the smart well completion is perfectly horizontal, the
true vertical depth remains at 10000 ft. This section of the completion is 650 ft long. Hence,
the measured depth should be 10700 ft. Again, we assume that the well is extending in the
direction of positive x, hence, the azimuth is 0 degree. In short, enter the following data in
this screen:
Measured depth
Feet
10050
10700
True Vertical Depth
Feet
10000
10000
Azimuth
Degree
0
0
Next, we proceed on to specify the tubing length, diameter, etc. These data can be entered
in the Equipment section, by clicking the tab labelled ‘Equipment’.
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100 - 164APPENDIX A – WORKED EXAMPLES
Figure A12.16:
Completion data entry
screen – Tubing flow
This section of the tubing has an internal diameter of 2.041” for its whole length of 650 ft.
Hence, input the following data:
Tubing Type
Start
Tubing
Measured Depth
Feet
10050
10700
Tubing ID
Inches
Tubing inside roughness
Inches
Rate multiplier
2.041
0.0006
1
The next step is to define the perforation details of this completion.
Figure A12.17:
Completion data entry
screen – Tubing flow
Since this section of the completion is meant for tubing flow only, i.e. no production or inflow
from reservoir, we can specify this section of the completion by introducing a very high skin,
say 5000, so that the production is negligible. The corresponding true vertical depths of the
perforation interval will be calculated automatically. In short, enter the following:
Perforation Interval MD Start
PETROLEUM EXPERTS LTD
Perforation Interval MD End
Skin Model Choice
Local Skin
APPENDIX A – WORKED EXAMPLES101 - 164
Feet
10050
Feet
10700
Enter by hand
5000
This completes the definition for completion Tubing. Next, we proceed on to Junction2. The
position of Junction2 is again totally dependent on the specification of the items upstream.
It’s position, i.e. measured and true vertical depths are calculated. To see the calculated
position, simply click on Junction2 on the equipment window on the right.
Figure A12.18:
Junction2 data entry
screen
The definition of completion ‘Annular’ is very similar to completion ‘Tubing’. The major
differences are:
•
•
•
The flow type of this completion is annular flow instead of tubing flow
The description of the deviation of this completion is different because it is no longer
extending towards the positive x direction. Contrary, it extends towards the negative
x direction. Hence, we have to adjust the value of the azimuth to model this situation
The perforation of this completion is divided into three segments
Bearing these differences in mind, we start the definition of completion Annular by clicking
on the completion labelled ‘Annular’ in the equipment list on the right hand side of the
window.
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Figure A12.19:
Completion data entry
screen – Annular flow
Enter the following data:
•
•
•
•
•
•
•
•
Horizontal Flow Model:
Vertical Flow Model:
Choke Model:
Flow Type:
Use Threshold Angle:
Threshold Angle:
Well bore Radius:
Dietz Shape Factor:
Beggs and Brill
Petroleum Experts 2
ELF
Annular Flow
No
45 degree
0.7083
31.6
To enter the deviation, the tubing length and diameter, etc. Click on the Input Data button on
the top right hand corner of the screen.
Figure A12.20:
Completion data entry
screen – Annular flow
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES103 - 164
We first describe the deviation. Since the smart well completion is perfectly horizontal, the
true vertical depth remains at 10000 ft. This section of the completion is 500 ft long. Hence,
the measured depth should be 11200 ft. But this time the well is extending in the negative x
direction, hence, the azimuth is 180 degree for this completion. In short, enter the following
data in this screen:
Measured depth
Feet
10700
11200
True Vertical Depth
Feet
10000
10000
Azimuth
Degree
0
180
Next, we proceed on to specify the tubing length, diameter, etc. These data can be entered
in the Equipment section, by clicking the tab labelled ‘Equipment’.
Figure A12.21:
Completion data entry
screen – Annular flow
This section of the casing has a internal diameter of 6.969”, tubing has an internal diameter
of 2.041” and an external diameter of 2 3/8”. Hence, input the following data:
Tubing
Type
Measured
Depth
Tubing
ID
Tubing inside
roughness
Tubing
OD
Casing
ID
Inches
Tubing
outside
roughness
Inches
Inches
Casing
inside
roughness
Inches
Feet
10700
11200
Inches
Inches
Start
Tubing
2.041
0.0006
2.375
0.0006
6.969
0.0006
The next step is to define the perforation details of this completion.
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Figure A12.22:
Completion data entry
screen – Annular flow
Since this section of the completion has three sections of perforation, the following data is
entered. The local skin is assumed to be zero.
Perforation Interval MD Start
Feet
10700
10900
11100
Perforation Interval MD End
Feet
10800
11000
11200
Skin Model Choice
Local Skin
Enter by hand
Enter by hand
Enter by hand
0
0
0
This completes the definition for completion ‘Annular’. Next, we proceed on to define the
reservoir by clicking on the reservoir item on the equipment window on the right.
Figure A12.23:
Reservoir data entry
screen
Enter the following for the reservoir model type and reservoir fluid properties:
•
•
Reservoir Model :
Reservoir Pressure :
PETROLEUM EXPERTS LTD
Darcy
6000 psig
APPENDIX A – WORKED EXAMPLES105 - 164
•
•
•
•
•
Oil Gravity :
Gas Gravity :
Water Salinity :
Water Cut :
Total GOR :
39 API
0.78 s.g.
100000 ppm
0 percent
500 scf/STB
Next, we need to define the reservoir parameter. This can be done by clicking on the ‘Input
Data’ button on the top right hand corner of the screen.
Figure A12.24:
Reservoir data entry
screen
Enter the following for the reservoir model:
•
•
•
•
•
Reservoir Permeability:
Reservoir Thickness:
Drainage Area:
Reservoir Top Depth:
Vertical Permeability:
20 mD
50 feet
500 acres
9975 feet
5 mD
This basically completes the model specification. Click | Done to leave the data entry screen.
To visualise the model constructed, from the PROSPER multilateral network window, we click
on | Visualise | Front to see the front view of the completion. The windows can be arranged
nicely by clicking on | Window | Tile.
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106 - 164APPENDIX A – WORKED EXAMPLES
Figure A12.25:
Network view and Front
view of the model
Calculating production rate from pressure
This section shows the user how to use the PROSPER multilateral option to calculate the
production rate from the reservoir by specifying a pressure at the tie point.
Click on | Analyse | Calculate:
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES107 - 164
Figure A12.26:
Multilateral calculation
screen
The Multilateral calculation screen will appear. Set the calculation option to One Point. Since
we are going to specify the tie point pressure, we set the Pressure or Rate Option to ‘Rate
from Pwf’. To see the production rate at 3000 psig tie point pressure, enter a value of 3000
psig in the Pressure entry box in the One point results section.
Then click on | Calculate. PROSPER will now do the calculation iteratively to find a solution.
This will take some time dependent on the speed of the computer.
Once the calculation is completed, the user can see the solution results by clicking the
button | Details under the One point results section.
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Figure A12.27:
Multilateral calculation branch and layer results
The overall production for a tie point pressure of 3000 psig will be around 11132STB/day.
The user can view the results for each branch, by selecting the branch of interest in the
Select Branch combo box. The results can be plotted by clicking on the | Plot button. To see
the pressure drop along the branches, in the plot window, click in | Variables. Then select all
three branches, set the Y-axis as measured depth and the X-axis as Pressure.
Figure A12.28:
Pressure along the
branches
It can be seen that the pressure drop along the Annulus is negligible if compared to the
pressure drop along the tubing. If the casing size is fixed, then there is a possibility of
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES109 - 164
increased production by increasing the tubing size. By increasing the tubing size, the
pressure drop in the tubing might be reduced significantly, and hence the production
increased.
Due to the restriction of the tubing used in the well bore (5 ½” OD, 4.778” ID), the maximum
tubing size that can be used in the completion is 3 ½” OD tubing. Below is a summary of the
tubing sizes that can be used.
Tubing option
1 (Base case)
2
Tubing OD
2 3/8”
3 ½”
Tubing ID
2.041”
2.922”
In order to see the effect of different tubing sizes, we have to change the model. Double click
on the Tubing completion and change the tubing ID to 2.922”:
Figure A12.29:
Changing the
tubing ID
We also need to change the tubing ID and OD in the annular section. Click on the
completion ‘Annular’ in the equipment list on the right and change the tubing ID to 2.922”
and OD to 3.5”.
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110 - 164APPENDIX A – WORKED EXAMPLES
Figure A12.30:
Changing the tubing ID
and OD
Click on | Done once finished.
The calculation should be repeated by clicking | Analyse | Calculate | Calculate. PROSPER
will recalculate the production. When the calculation stop, click on | Details and a total
production of around 12230 STB/day is observed, i.e. about 1100 STB/day increment in
production. Hence, we will use a 3 ½” tubing for the design.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES111 - 164
Creating the IPR curve
This section shows the user how to generate an IPR curve for the completion. From the
PROSPER multilateral network window, click on | Analyse | Calculate. In order to calculate a
curve, set the calculation option to Curve.
Figure A12.31:
Calculating a IPR curve
Under the Curve Calculation section, set the Minimum Pressure as 10 psig and the Number
of Points as 10. Click on | Calculate to start the IPR calculation. The calculation will take
some time, dependent on the speed of the computer. Click on | Plot to see the IPR after the
calculation has finished.
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112 - 164APPENDIX A – WORKED EXAMPLES
Figure A12.32:
IPR curve for the smart
well completion
Click on | Finish to return to the PROSPER multilateral network window.
System Calculation
Once the inflow performance has been generated, it can be used to determine the
production rate given a wellhead pressure.
Exit the PROSPER Multilateral Network window by clicking on | Finish | Done. In the
PROSPER main screen, click on | Calculation | System (IPR + VLP).
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES113 - 164
Figure A12.33:
System calculation
We are going to determine the production rate for a wellhead pressure of 200 psig. Set the
following data in the System calculation screen:
•
•
•
•
•
Top Node Pressure:
Surface Equipment Correlation:
Vertical Lift Correlation:
Solution Node:
Rate Method:
200 psig
Dukler Flannigan
Petroleum Experts 2
Bottom Node
Automatic – Linear
Click on | Continue. We are not going to do any sensitivity studies. However, note that in
System Calculation for multilateral option, only the sensitivity variables that are affecting the
lift curve can be chosen. Those sensitivity variables that are affecting both the IPR and VLP
cannot be chosen since multilateral IPR model is much more complex than the ordinary
single branch IPR.
Click on | Continue | Calculate to start the calculation. Click on | Plot to see the solution. The
calculation shows that a production of around 12700 STB/day can be achieved.
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114 - 164APPENDIX A – WORKED EXAMPLES
Figure A12.34:
System calculation
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES115 - 164
A13 Example 13 - Gas Injector with down-hole chokes using Multilateral model
File: ~/samples/PROSPER/multilat3.out
The objectives of this example are to:
• Go through the step by step procedure for defining a multi-lateral gas injector.
• Determine the gas injection rate into the reservoirs for a series of wellhead
pressures.
• See the effect of varying the choke opening on the injectivity.
This example demonstrates how to:
• Build multi-lateral gas injectors in PROSPER.
• How to perform sensitivity calculation in multilateral wells.
This example can be found in the samples directory under the name of MULTILAT3.OUT
file. However following the steps indicated below, you would be able to generate the model
from scratch.
The example that we will be setting is as described in the sketch below:
Figure A13.1:
Sketch of the
Completion
TIE POINT @ 13000
Reservoir 1 Top
@ 13103 feet
Reservo
Reservoir 2 Top
@ 15206 feet
Reservo
Tubing ID=4.67”
Tubing OD=5.5”
Casing ID=8.5”
•
•
•
•
The well is a straight hole completion with injection catering to two different reservoirs,
separated from each other by approximately 100 feet.
The flow paths are as drawn by the arrows.
The flow comes through the 5.5” tubing and at 13103 feet TVD it splits into two parts one
going through the top choke into the annulus and subsequently into the top reservoir.
The rest of the tubing flow continues downwards, and goes through the bottom choke
from tubing to annulus and to bottom reservoir.
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116 - 164APPENDIX A – WORKED EXAMPLES
A Note about Tie Point
The tie point defined at 13000 feet of TVD is the point above which
everything will be a part of well bore sketch and thus the pressure loss etc
in that section will be a part of VLP. Everything below the tie point is a part
of the IPR and pressure losses in this section will be evaluated in IPR
calculations.
A13.1
Defining the System Set Up
1. Begin by starting the program. From the PROSPER main menu, select File  New to
reinitialise the program input and output files. The ‘New’ menu item under File is only
available if a file has already been loaded. If there is no file loaded skip this step
and go to next step.
2. To begin setting up the system options, select Options Options or double-click on the
‘SUMMARY DATA’ area and make the following selections:
•
•
•
•
•
•
•
•
•
•
•
•
Fluid:
Method:
Separator:
Flow type:
Well type:
Predict:
Model:
Range:
Output:
Type:
Gravel pack:
Reservoir:
Dry and Wet Gas
Black Oil
Single-Stage Separator
Tubing Flow
Injector
Pressure and Temperature (Offshore)
Rough Approximation
Full System
Show Calculating Data
Cased Hole
No
Multi-Lateral well.
Then click Done to exit this screen. This completes the system setup and reinitialises the
program and governs the inputs that the user will be required to enter.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES117 - 164
A13.2
Entering the PVT data
1. In this section we will enter the PVT input data required.
2. Select the PVT menu in the main screen.
•
Click Input data
or
•
Double-click on the ‘PVT DATA’ area of the main screen and enter the following:
Gas Gravity:
Separator Pressure:
Condensate to Gas Ratio:
Condensate Gravity:
Water to Gas Ratio:
Water Salinity:
Mole Percent H2S:
Mole Percent CO2:
Mole Percent N2:
0.65
9000 Psig
0.0
STB/MMSCF
35
API
0
STB/MMscf
150000 ppm
0%
0%
0%
Figure A13.2:
PVT Input Screen
For this case we are using Lee et.al as the correlation to predict gas
viscosities. We also are not matching to any laboratory data.
Click Done on the above screen to exit. This marks the end of defining the PVT behaviour
SEPTEMBER 2003
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118 - 164APPENDIX A – WORKED EXAMPLES
A13.3
•
Entering the Equipment data
The next task is to define the well bore itself and surface lines (if any). This is done in the
following steps.
•
Click System  Equipment (Tubing etc) on the main PROSPER screen
Or
•
Double-click on the ‘EQUIPMENT DATA’ area
•
Then click All  Edit
The program will automatically lead you through the required equipment data screens
starting with the well deviation survey. Enter the following into the deviation survey data
table:
Measured
Depth
(feet)
0
13000
True
Vertical
Depth
(feet)
0
13000
While entering the deviation survey, PROSPER calculates automatically the cumulative
displacement and the angle of the well.
•
•
•
Click Done to continue to the surface equipment screen
Click Cancel to enter NO surface flow line data
The down-hole equipment screen will then appear. Enter the data in the screen
as follows
Figure A13.3:
Down hole Equipment
Input Data Screen
•
The well has 4.67" ID tubing down to 13000 ft, which is the tie point.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES119 - 164
•
Click on the Type cells to get a combo box of options and enter the following
down hole equipment:
Type
Xmas tree
Tubing
•
Measured
Depth
(feet)
0
13000
IDs
Roughness
(ins)
(ins)
4.67
0.0006
Click Done to advance to the geothermal data entry screen. Once on the screen,
enter the following temperature profile:
Measured
Depth
(feet)
0
13000
Formation
Temperature
(deg F)
60
270
Enter an overall heat transfer coefficient of 3 Btu/hr/ft2/F. Click | Done to exit the
screen.
•
This takes you to the default heat capacity screen. Let it remain as it is. Click on
Done to go to the next screen.
•
Now enter the injected fluid temperature as 135 F in the next screen.
Figure A13.4:
Equipment Input Screen
This completes the equipment input for the well.
Click Summary and check that the equipment input data is consistent. As a further check
click Draw Down hole.
SEPTEMBER 2003
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120 - 164APPENDIX A – WORKED EXAMPLES
Figure A13.5:
Well Bore Sketch
When satisfied that the well equipment is correct, click Main to return to the PROSPER main.
A13.4
Defining the IPR data (Inflow)
This example assumes that the user is familiar with drawing the multi-lateral IPR
sketches in PROSPER. If you need assistance in that area, please refer the section 7.8
of the manual or Example A11 for the details.
The next task is to enter the Inflow Performance model as follows:
•
Click System  Inflow performance
Or
•
Double-click on the ‘IPR DATA’ area
When entering the IPR section, the first entry screen that appears asks for the injected fluid
PVT data. Supply the following data:
Gas Gravity:
Condensate to Gas Ratio:
Water to Gas Ratio:
Water Salinity:
As shown in the following screen.
PETROLEUM EXPERTS LTD
0.65
0.0
STB/MMscf
0.0
STB/MMscf
150000 ppm
APPENDIX A – WORKED EXAMPLES121 - 164
Figure A13.6:
Injection Gas PVT Input
Screen
122 - 164APPENDIX A – WORKED EXAMPLES
•
A Sketch drawn on basis of this will look as shown below
Figure A13.8:
Down hole network
System Drawing
The next task is to define the various components as drawn in the above screen. We will
start from the tie point and work our way towards the reservoirs.
•
Defining the Tie Point .
The tie point is at (13000, 13000) feet. On the above drawing double click on the tie
point. A screen appears and enter the data as shown:
Figure A13.9:
Tie point Input data
screen
Please note that on the right hand side of the input screen there is a
window that has all the components of the drawing listed in it. You can
proceed with data by clicking the next piece of equipment on this window.
This window will be always available during the whole process of data
entry.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES123 - 164
•
Defining the Tubing up to the Junction
The junction is the point where the fluids from the two reservoirs commingle; it is
at a depth of (13100, 13100) and is connected to the tubing with a 4.67” ID
tubing.
The tubing information entry is a two-step process. First we define the model for
pressure loss calculations. We will also be using the following model:
Horizontal Flow Model:
Vertical Flow Model:
Choke Model:
Flow Type:
Correlation Threshold:
Threshold Angle:
Well Bore radius:
Beggs and Brill
Petroleum Experts 2
ELF
Tubing
No
45 Degrees
0.75 feet
i)
In well bore pressure computations, selecting the correlation
threshold option as “Yes” gives the flexibility of changing from
vertical flow model to a horizontal flow modelling case the angle
with vertical exceeds the threshold angle defined. We are not using
this option however PROSPER requires you to define the threshold
angle and horizontal flow model even though these will not be used
in calculations.
ii)
Defining the flow model will be needed at equipment level as we go
on. We will be using the same models unless otherwise noted.
The screens for entering the tubing flow model are as shown below:
Figure A13.10:
Tubing Model Selection
screen
Once the model is entered, if on the above screen the Input Data button is pressed, the next
screen is displayed, where the deviation survey, including the azimuth, is to be entered.
SEPTEMBER 2003
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124 - 164APPENDIX A – WORKED EXAMPLES
Measured
Depth
(feet)
13000
13100
True
Vertical
Depth
(feet)
13000
13100
Azimuth
0
0
Figure A13.11:
Tubing deviation survey
Input Screen
Note that for all the pieces of downhole equipment where the deviation
survey needs to be specified, PROSPER will calculate the measured depth
and TVD of the starting point automatically. For example in this the starting
point is at (13000,13000).
Once the deviation survey is entered we will need to enter the equipment information, like
the tubing diameters etc, in the next screen. This screen is accessed by clicking on the TAB
called EQUIPMENT in the bottom left hand corner of the screen shown above.
Tubing
Type
Start
Tubing
PETROLEUM EXPERTS LTD
Measured
Depth
(feet)
13000
13100
IDs
Roughness
(ins)
(ins)
4.67
0.0006
APPENDIX A – WORKED EXAMPLES125 - 164
Figure A13.12:
Tubing description Input
Screen
This finishes the entry of tubing information.
•
Defining the Junction
To proceed to the next item, which is the junction called Com. Point, click on its icon in
the view screen showing all the items on the right hand side of the screen shown in the
figure above. The following screen is displayed:
Figure A13.13:
Junction Data Screen
Note that for this screen the TVD and measured depth have automatically
been picked up from the last point entered for the tubing, which is
(13100,13100).
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126 - 164APPENDIX A – WORKED EXAMPLES
•
Defining the first completion
The completions are all defined in a similar way to the tubing, i.e. we have to define the
following:
I)
II)
III)
Defining the flow Model
Defining the deviation survey
Defining the equipment.
The information for this part of the input for top completion is as follows
The Flow Model
Horizontal Flow Model:
Vertical Flow Model:
Choke Model:
Flow Type:
Correlation Threshold:
Threshold Angle:
Well Bore radius:
Dietz Shape Factor:
Beggs and Brill
Petroleum Experts 2
ELF
Annular
No
45 Degrees
0.75 feet
31.6
Figure A13.14:
Top Completion Model
Input Screen
The Deviation Survey
Measured
Depth
(feet)
13100
13203
PETROLEUM EXPERTS LTD
True
Vertical
Depth
(feet)
13100
13203
Azimuth
0
0
APPENDIX A – WORKED EXAMPLES127 - 164
Figure A13.15:
Top Completion
Deviation Survey Input
Screen
The Equipment
Tubing
Type
Measured
Depth
(feet)
Start
Casing
Choke
Tubing
13100
13103
13103
13203
Tubing
ID
(ins)
4.67
4.67
Tubing
Inside
Roughness
(ins)
0.0006
Tubing
OD
(ins)
5.5
Tubing
Outside
Roughness
(ins)
0.0006
Casing
ID
(ins)
Casing
Inside
Roughness
(ins)
4.67
0.0006
8.5
0.0006
Note that we have defined the main flow type as annular but have tubing
flow from 13100 to 13103. This is done by using the casing in that bit of the
equipment description
Figure A13.16:
Top Completion
equipment description
Input Screen
SEPTEMBER 2003
PROSPER MANUAL
128 - 164APPENDIX A – WORKED EXAMPLES
Perforation Details
In the completion section, the additional piece of data entered is the detail of the
perforations. We need to define the measured depth\ TVD where the completion has
been perforated. For the top completion we have perforations all along the reservoir
thickness of 100 feet.
Start
Measured
Depth
(feet)
13103
End
Measured
Depth
(feet)
13203
Non-Darcy
Skin
Local Skin
Calculated
0
Note that we have defined the perforation interval in terms of the measured
depth. The program will calculate true vertical depths automatically on
basis of the deviation survey entered for the completion. You could also
enter the true vertical depth and the measured depths will be calculated
automatically.
This data is entered in the perforation details screen, which is accessed by clicking on the
PERFORATION DETAILS Tab as shown above.
Figure A13.17:
Top Completion
Perforation Input Screen
•
To enter the skin data scroll towards the right hand side of the data entry screen,
by using the bottom scroll bar
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES129 - 164
Figure A13.18:
Perforation Input Screen
i)
You could use the various skin models to calculate the local
geometric and Non-Darcy skin on this screen, by changing the Skin
Model / Non Darcy entry Method choice from enter by hand to the
applicable one.
ii)
If we had selected the Gravel Pack option in the main option screen
in step1 of this example, the gravel pack entry screen would be
available as well.
The local is zero for the top completion. To calculate the Non-Darcy factor, hit on the
‘Calculate’ button. Enter the reservoir permeability (50 mD) and click on ‘Done’ to
calculate the Non-Darcy factor. The calculated value will be displayed on the screen.
This finishes the data entry for the top completion.
•
Defining the Top Reservoir
The next step is defining the top reservoir. To go to the reservoir data entry screen,
click on the top reservoir in the right hand window of the above screen.
The Top Reservoir Model
Reservoir Model:
Reservoir pressure:
Reservoir Temperature:
Condensate Gravity:
Gas Gravity:
Water salinity:
Water to gas ratio:
Condensate to gas ratio:
Petroleum Experts
8600 Psig
270 F
35 API
0.65
150,000 ppm
0.0 STB/MMSCF
0.0 STB/MMSCF
The reservoir Pressure is defined at the reservoir top.
SEPTEMBER 2003
PROSPER MANUAL
130 - 164APPENDIX A – WORKED EXAMPLES
Figure A13.19:
Top reservoir Model Input
Screen
The next step is specify the reservoir characteristics. This is done by pressing the
INPUT DATA button on the above screen.
Top Reservoir Parameters
Reservoir Permeability:
Reservoir Thickness:
Drainage Area:
Reservoir Top depth:
Vertical Permeability:
Time since injection start:
Reservoir Porosity:
Connate water saturation:
50
100
500
13103 feet
10
1000
0.15
0.2
Figure A13.20:
Top reservoir Input
Screen
This completes the top reservoir data entry.
•
Defining the bottom completion
PETROLEUM EXPERTS LTD
mD
feet
acres
mD
days
fraction
fraction
APPENDIX A – WORKED EXAMPLES131 - 164
The Flow Model
Horizontal Flow Model:
Vertical Flow Model:
Choke Model:
Flow Type:
Correlation Threshold:
Threshold Angle:
Well Bore radius:
Dietz Shape Factor:
Beggs and Brill
Petroleum Experts 2
ELF
Annular
No
45 Degrees
0.75 feet
31.6
Figure A13.21:
Bottom Completion
Model Input Screen
The Deviation Survey
Measured
Depth
(feet)
13100
15306
SEPTEMBER 2003
True
Vertical
Depth
(feet)
13100
15306
Azimuth
0
0
PROSPER MANUAL
132 - 164APPENDIX A – WORKED EXAMPLES
Figure A13.22:
Bottom Completion
Deviation Survey Input
Screen
The Equipment
Tubing
Type
Measured
Depth
(feet)
Start
Casing
Choke
Tubing
13100
15206
15206
15306
Tubing
ID
(ins)
4.67
4.67
Tubing
Inside
Roughness
(ins)
0.0006
Tubing
OD
(ins)
5.5
Tubing
Outside
Roughness
(ins)
0.0006
Casing
ID
(ins)
Casing
Inside
Roughness
(ins)
4.67
0.0006
8.5
0.0006
Note that we have defined the main flow type as annular but have tubing
flow from 13100 to 15206. This is done by using the casing in that bit of the
equipment description
Figure A13.23:
Bottom Completion
Equipment description
Input Screen
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES133 - 164
Perforation Details
For the bottom completion we have perforations all along the bottom reservoir
thickness of 100 feet.
Start
Measured
Depth
(feet)
15206
End
Measured
Depth
(feet)
15306
Non-Darcy
Skin
Local Skin
Calculated
0
Figure A13.24:
Bottom Completion
Perforation Input Screen
To enter the skin data, scroll towards the right hand side of the data entry screen by using
the bottom scroll bar.
The local is zero for the bottom completion. To calculate the Non-Darcy factor, hit on the
‘Calculate’ button. Enter the reservoir permeability (50 mD) and click on ‘Done’ to calculate
the Non-Darcy factor. The calculated value will be displayed on the screen.
SEPTEMBER 2003
PROSPER MANUAL
134 - 164APPENDIX A – WORKED EXAMPLES
Figure A13.25:
Perforation Input Screen
This finishes the data entry for the bottom completion.
• Defining the Bottom Reservoir
The next step is defining the bottom reservoir. To go to the reservoir data entry
screen, click on the bottom reservoir in the right hand window of the above screen.
Bottom Reservoir Model
Reservoir Model:
Reservoir pressure:
Reservoir Temperature:
Condensate Gravity:
Gas Gravity:
Water salinity:
Water to gas ratio:
Condensate to gas ratio:
Figure A13.26:
Bottom Reservoir
Model Input Screen
PETROLEUM EXPERTS LTD
Petroleum Experts
8600 Psig
300 F
35 API
0.65
150,000 ppm
0.0 STB/MMSCF
0.0 STB/MMSCF
APPENDIX A – WORKED EXAMPLES135 - 164
Bottom Reservoir Parameters
Reservoir Permeability:
Reservoir Thickness:
100
Drainage Area:
Reservoir Top depth:
15206
Vertical Permeability:
10
Time since injection start:
Reservoir Porosity:
Connate water saturation:
50
mD
feet
500
feet
acres
mD
1000
0.2
0.2
days
fraction
fraction
Figure A13.27:
Bottom reservoir
Input Screen
This completes data entry. Click on Done to exit to the main drawing of the system.
The next step is to visualise the system defined. To see the system defined on the main
drawing screen click on, VISUALISE | ALL as shown in the figure below.
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136 - 164APPENDIX A – WORKED EXAMPLES
Figure A13.28:
Invoking Visualisation
of the System
Once this is done, we can see the Top, Side and Front view of the completion system
defined as shown in the following figure.
Figure A13.29:
Different views of the
completions
Once we have established that the system is okay, we need to generate the IPR for the
system. This is done by clicking on ANALYZE | CALCULATE on the above screen. Once
this is done the calculate screen appears as shown below:
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES137 - 164
Figure A13.30:
IPR Calculation
Option screen
On this screen, there are various Calculation options; we will select the following options
and hit Calculate.
Point Or Curve:
Conductivity Switch:
Allow cross-flow:
Minimum Pressure:
Number of Points:
Curve
Finite Conductivity
No
12000 Psig
10
i)
Curve Option allows the user to generate the whole IPR curve. The
user can also use this screen do a point calculation and see the
pressure/ production profiles along the whole network.
ii)
There are two point calculations available, one is calculating rate
from bottom hole pressures and other is calculating pressure for a
given rate at tie point.
iii)
The Conductivity switch is to use/ ignore the pressure loss in the
completion during the calculations. Selecting ‘Finite conductivity’
includes pressure loss in IPR calculations.
iv)
The minimum pressure for producers is the minimum tie point
pressure below which no calculations will be made. For injectors it
is the highest pressure at tie point above which no calculations will
be made.
v)
The number points is the number of calculations that are made to
generate the IPR curve
SEPTEMBER 2003
PROSPER MANUAL
138 - 164APPENDIX A – WORKED EXAMPLES
On basis of these options, the IPR of the system is as follows:
Figure A13.31:
IPR of the
Injection Well
On the IPR Plot Click Main to take you to the multi-lateral drawing. Click | Finish |
APPENDIX A – WORKED EXAMPLES139 - 164
Figure A13.32:
System Calculation
Input Data screen
•
Once this screen is defined, we want the wellhead injection pressure to be a sensitivity
variable. To define that on this screen, press Continue. This takes us to the next screen,
where the sensitivities variables are selected as indicated
Figure A13.33:
Sensitivity Variable
Selection screen
•
As soon as you select this variable another screen for defining the values of this variable
comes up. Enter the five values in this from 7000 Psig to 8000 Psig as shown below
SEPTEMBER 2003
PROSPER MANUAL
140 - 164APPENDIX A – WORKED EXAMPLES
Figure A13.34:
Sensitivity Variable
value Input screen
•
•
•
Once the values are defined click on Done.
Click on Continue on the next screen.
Click on Calculate on the next screen.
Figure A13.35
System Solution
Calculation Screen
•
Once the calculations are finished on the calculation screen, hit on Sensitivity. The
sensitivity plot is shown. On this plot click on Variable and select the Gas Rate as
variable. This gives us the plot of gas injection rate versus the well head pressures:
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES141 - 164
Figure A13.36
Gas Injection
Rate versus well
head pressure
If we want to look at the pressure and production profiles, in the completion for one of the
cases, On the main calculation screen shown below press on Solution Details:
Figure A 13.37
Accessing
Solution Details
Once the solution details is pressed the following screen with the details of the solution
comes up. This screen gives the details of pressure temperature, density etc at the well
head and tie point.
SEPTEMBER 2003
PROSPER MANUAL
142 - 164APPENDIX A – WORKED EXAMPLES
Figure A13.38
Solution Details
On the solution details screen, we can go into further details of the inflow, if we press Inflow
Layer Details button as shown above.
Figure A13.39
Inflow Layer
Details
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES143 - 164
On this screen Press on Plot. On the plot screen, by going to variable screen, we can select
the completions, and variables we want to see. Following are some of these plots.
Figure A13.40
Top Completion
Pressure and
reservoir
pressure
variation
Figure A13.41
Top Completion
Rate per unit
length
SEPTEMBER 2003
PROSPER MANUAL
144 - 164APPENDIX A – WORKED EXAMPLES
i)
You can plot the details for other completions, tubing etc as well by
selecting the appropriate variables by going to the top section of the
plot.
ii)
If you want to do sensitivity on various inflow variables like down-hole
choke sizes, reservoir pressures, perforation intervals etc, go back to
the IPR section, make the changes and regenerate the whole IPR
curve, before doing sensitivities again.
A14 Example Using Multi-lateral model and PCP
A vertical well was producing from a lower layer and then a re-entry from the same well was
developed to an upper zone and be able to produce from the two zones simultaneously.
How to set up the model
The objectives of this example are to:
• Go through the step by step procedure for defining a multi-lateral well
• Determine how much the multilateral well would produce considering the PCP.
Note: To be able to build this model, the user must set the pump and the
rod database first. To learn how to set up the correspondent database for
Progressive Cavity Pumps the user must refer to Chapter 11 section 11.7.1
of PROSPER manual.
Figure A14.1
Well Sketch that displays
the drilling program and
completion.
The multilateral data entry screen is accessed by choosing | System | Inflow Performance
from the PROSPER main menu, as with the single well IPR.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES145 - 164
Figure A14.2
System Summary
Inflow type: Multilateral
Begin by starting the program. From the PROSPER main menu, select File  New to
reinitialise the program input and output files.
The ‘New’ menu item under File is only available if a file has already been loaded. If
there is no file loaded skip this step and go to next step.
•
To begin setting up the system options, select Options Options or double-click on the
‘SUMMARY DATA’ area and make the following selections:
•
•
•
•
•
•
•
•
Fluid:
Method:
Separator:
Flow type:
Well type:
Predict:
Model:
Range:
•
•
Type:
Gravel pack:
Reservoir:
•
•
Oil and Water
Black Oil
Single-Stage Separator
Tubing Flow
Producer
Pressure and Temperature (Offshore)
Rough Approximation
Full System
Output:
Show Calculating Data
Cased Hole
No
Multi-Lateral well.
Then click Done to exit this screen. This completes the system setup and reinitialises
the program and governs the inputs that the user will be required to enter.
Entering the PVT data
In this section we will enter the PVT input data required.
Select the PVT menu in the main screen.
• Click Input data
or
•
Double-click on the ‘PVT DATA’ area of the main screen and enter the
following:
Solution GOR:
Oil Gravity:
SEPTEMBER 2003
100
13
scf/stb
API
PROSPER MANUAL
146 - 164APPENDIX A – WORKED EXAMPLES
Gas Gravity
Water Salinity
Mole Percent H2S:
Mole Percent CO2:
Mole Percent N2:
0.67
10000 ppm
0%
0%
0%
Figure A14.3:
PVT Input Screen
Click Done on the above screen to exit. This marks the end of defining the PVT behaviour
Entering the Equipment data
The next task is to define the well bore itself and surface lines (if any). This is done in the
following steps.
•
Click System  Equipment (Tubing etc) on the main PROSPER screen
or
•
Double-click on the ‘EQUIPMENT DATA’ area
Then click All  Edit
The program will automatically lead you through the required equipment data screens,
starting with the well deviation survey. Enter the following into the deviation survey data
table:
Measured
Depth
(feet)
0
4000
True
Vertical
Depth
(feet)
0
4000
While entering the deviation survey, PROSPER calculates automatically the cumulative
displacement and the angle of the well.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES147 - 164
•
•
Click Done to continue to the surface equipment screen
Click Cancel to enter NO surface flow line data
The down-hole equipment screen will then appear. Enter the data in the screen as follows:
•
The well has 2.89" ID tubing down to 5000 ft, which is the tie point.
Click on the Type cells to get a combo box of options and enter the following downhole
equipment:
Type
Measured
Depth
(feet)
IDs
Roughnes
s
(ins)
(ins)
Xmas tree
Tubing
0
4000
2.89
0.0006
Figure A14..4:
Equipment Input Screen
•
Click Done to advance to the geothermal data entry screen. Once on the screen,
enter the following temperature profile:
Measured
Depth
(feet)
0
4000
Formation
Temperature
(deg F)
60
159
Enter an overall heat transfer coefficient of 8 Btu/hr/ft2/F. Click | Done to exit the screen.
•
This takes you to the default heat capacity screen. Let it remain as it is. Click on
Done to go to the next screen.
SEPTEMBER 2003
PROSPER MANUAL
148 - 164APPENDIX A – WORKED EXAMPLES
Figure A14.5:
Geothermal Gradient
This completes the equipment input for the well.
When satisfied that, the well equipment is correct. Click Main to return to the PROSPER main
screen.
Notes about Equipment Data Entry Screens
v)
Make sure that the measured depth of last piece of equipment in
the downhole equipment is same as the last depth in the
geothermal gradient.
vi)
All measured depths in the downhole equipment are converted to
true vertical depths as per the deviation survey entered. Thus the
deepest point of the deviation survey should be at least as deep as
last point of equipment / geothermal gradient.
vii)
The geothermal gradient should have a temperature entry
corresponding to depth of wellhead.
viii)
If you have a pipeline in the system, the upstream end of the
pipeline should tally with wellhead depth.
Available data for the Top and bottom layer
Top layer:
Reservoir Pressure
Reservoir Temperature
Oil Gravity
Gas Gravity
Water Salinity
Water Cut
Total GOR
Horizontal Permeability
Formation Thickness
Drainage Area
Depth of Reservoir Top
Vertical Permeability 300
PETROLEUM EXPERTS LTD
1900
160
13
0.67
10000
0
100
300
140
500
4050
md
psig
degrees F
API
sp. gravity
ppm
percent
scf/STB
md
feet
acres
feet
APPENDIX A – WORKED EXAMPLES149 - 164
Bottom Layer
Reservoir Pressure 2000
Reservoir Temperature
Oil Gravity
Gas Gravity
Water Salinity
Water Cut
Total GOR
Horizontal Permeability
Formation Thickness
Drainage Area
Depth of Reservoir Top
Vertical Permeability 210
psig
160
13
0.67
10000
0
100
210
200
400
4200
md
degrees F
API
sp. gravity
ppm
percent
scf/STB
md
feet
acres
feet
According to the drilling program, the tie point will be considered at measured depth of 9700
ft (8800 ft vertical depth). The deviation survey of the original well and the side track are
indicated below.
Completion 1
Measured
Depth
feet
4050
4090
4150
4300
4330
Vertical
depth
feet
4050
4090
4140
4200
4210
Azimuth
Vertical
Depth
feet
4050
4400
Azimuth
degrees
0
0
0
0
0
Vertical
section
Measured
Depth
feet
4050
4400
degrees
0
0
The user interface consists of a framework window that contains several child windows, as
well as the menu and toolbar from which commands are issued. The child windows include
the network windows that contain the system network drawing, the navigator window that
can assist in the viewing of large networks and up to three visualisation windows, which can
show the multilateral network drawn to scale from three orthogonal points of view.
SEPTEMBER 2003
PROSPER MANUAL
150 - 164APPENDIX A – WORKED EXAMPLES
Figure A14.6
PROSPER
Multilateral
Network
To start drawing your multilateral system according to the well sketch, start selecting the tie
point , junction, Completion (1) and Completion (side track) as well as the top and bottom
reservoir.
Figure A14.7
Adding the
completion and
reservoirs
Once drafted the basic drawing according to your well sketch and drilling program, it is
possible to connect the blocks using the button Add Link.
To enter the required data for each section all you have to do is to double click on each icon.
It is recommended to start from the tie point to the reservoir according to the well sketch.
A Note about Tie Point
The tie point is the point above which everything will be part of wellbore sketch
and thus the pressure loss etc in that section will be a part of VLP. Everything
below the tie point is a part of the IPR and pressure losses in this section will be
evaluated in IPR calculations.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES151 - 164
Figure A14.8
Linking the tie
point with the joint,
completion and
reservoir.
After double clicking on the tie point, enter the measured depth and true vertical depth as
indicated previously. The tie point is the node where the IPR is solved, and is located at the
top of the system (in vertical depth). Hence, the tie-point can only be a starting point.
The Junction point will be a branching node. It can only have one link into it (from a tie-point
or a completion).
Once these two points have been defined, then Deviation Survey, Downhole Equipment and
Perforation Details can be entered. In the case of the Deviation Survey, there is an
additional azimuth entry.
When the user has entered the information for each branch, the calculations can be
performed.
Tie point :
Data: Measured depth of 4000 ft , True Vertical Depth of 4000 ft
Junction 1:
The tubing information entry is a two step process. First we define the model for pressure
loss calculations. We will also be using the following model:
Horizontal Flow Model:
Vertical Flow Model:
Choke Model:
Flow Type:
Correlation Threshold:
Threshold Angle:
Well Bore radius:
Beggs and Brill
Petroleum Experts 2
ELF
Tubing
No
45 Degrees
0.43 feet
Completion 1:
The screens for entering the flow model are as shown below:
SEPTEMBER 2003
PROSPER MANUAL
152 - 164APPENDIX A – WORKED EXAMPLES
Figure A14.9
Tubing Model Selection
screen
Once the model is entered, selecting the Input Data button, the following screen is displayed,
where the deviation survey, including the azimuth, can be entered:
Measured
Depth
(feet)
True
Vertical
Depth
(feet)
Azimuth
4050
4400
4050
4400
0
0
Figure A14.10
Tubing deviation survey
Input Screen
Once the deviation survey is entered, we will need to enter the equipment information like
the tubing diameters etc, in the following screen. This screen is accessed by clicking on the
TAB called EQUIPMENT in the bottom left hand corner of the screen shown above.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES153 - 164
Tubing
Type
Measured
Depth
(feet)
IDs
Roughnes
s
(ins)
(ins)
Start
Tubing
4050
4500
2.89
0.0006
Figure A14.11
Tubing description Input
Screen
This finishes the entry of tubing information.
According to the drilling program, this completion has been perforated from 4200 ft to 4400
ft.
Figure A14.12
Vertical well
Perforation details
SEPTEMBER 2003
PROSPER MANUAL
154 - 164APPENDIX A – WORKED EXAMPLES
Re entry 1 (completion 2 multilateral)
Then double click on completion 2, labelled Re entry.
Select the information required such as vertical flow model, well bore radius, and Dietz
shape factor.
For this example the Petroleum Experts 2 correlation will be used, a well bore radius of 0.345 ft
and Dietz shape factor of 30 will be considered.
Figure A14.13
Re entry 1,
Calculation options
screen.
When pressing the option Input Data, there are three tabbed dialogs in this data input
screen, which allow the entry of a deviation survey, equipment descriptions and completion
information. The first two dialogs contain tables very similar to the ones encountered by
selecting System | Equipment from the PROSPER main menu and then the ‘Deviation
Survey’ and ‘Downhole Equipment’ buttons. In the case of the deviation survey there is
an additional azimuth entry.
Enter first the deviation survey:
Figure A14.14
Re entry
Deviation Survey
Screen
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES155 - 164
Once entered the deviation survey, select the equipment and select tubing, according to
the deviation survey, the tubing in the completion 1 has been run down to 4330 ft and has a
diameter of 2.89 in.
Figure A14.15
Re entry
Equipment
According to the drilling program, this completion has been perforated from 4100 ft to 4250
ft:
Figure A14.16
Completion 1
Perforation details
Finally double click on the reservoir and enter the PVT data, as well as the information
required to calculate the inflow performance based on the Darcy Model.
The information has been provided at the beginning of this example.
SEPTEMBER 2003
PROSPER MANUAL
156 - 164APPENDIX A – WORKED EXAMPLES
Figure A14.17
Lower sand
PVT Data
Press Input Data to continue and enter the information for the reservoir:
Figure A14.18
Bottom Reservoir
Inflow data
based on
Darcy Reservoir
Model
Now the correspondent data for the second sand can be entered.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES157 - 164
Figure A 14.19
Re entry
PVT Data
Select input data and enter first the deviation survey.
Figure A14.20
Re entry
Input Data
Press input to continue and enter the information for the reservoir.
Once you enter the information for the two branches (completion 1 and side track), from
PROSPER – Multilateral Network Menu, select the option Visualise all:
SEPTEMBER 2003
PROSPER MANUAL
158 - 164APPENDIX A – WORKED EXAMPLES
Figure A14.21
Visualise All
From PROSPER – Multilateral Network Menu, select the option Analyse/Calculate
The Calculate screen gives the option of calculating one IPR point or a curve.
Also, calculations can be switched between infinite and finite conductivity modes of
calculation. In the latter case the pressure drop in the tubing is taken into account.
Figure A14.22
Calculate
The finite conductivity solution takes in account the pressure drop and interference, whilst
the Infinite conductivity considers equal pressure and constant production rate at all times.
The flow distribution is used then to calculate the pressure around the source.
APPENDIX A – WORKED EXAMPLES159 - 164
The pressure of the reservoir approaches a constant value, then if in one particular branch in
the reservoir is surrounded by a constant pressure boundary, the pressure in the well and
the boundary will become constant (steady state pressure), when the steady state pressure
is normalized respect to the flow rate, it provides a measure of the pressure draw-down
required to flow a unit of volume per unit time.
The Details button is used to display pressure and rate-related parameters with respect to
the measured and vertical tubing depths of each branch. If a curve has been calculated,
these details pertain to the last point in the curve.
Figure A14.23
Plot
From the PROSPER main screen just perform a nodal analysis without the PCP pump to
determine if the well is capable to flow on its own.
The well has a wellhead pressure of 120 psig
SEPTEMBER 2003
PROSPER MANUAL
160 - 164APPENDIX A – WORKED EXAMPLES
Figure A14.24
Calculation
IPR+VLP
VLP / IPR calculations:
Figure A14.25
VLP IPR results
Notice that with out the pump and based on the nodal analysis the well can produce only
120 bpd.
In order to be able to set a Progressive Cavity Pump, you will have to set the Pump And Rod
string database as explained in the previous example.
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES161 - 164
Provided the fact that you have the pump database set up according to data provided by the
manufacture then you can set from the main screen the PCP.
Progressive Cavity Pump set up
Figure A14.26
PCP
Based on the completion program, the pump is to be set at 3900 ft, and it is expected to
produce 700 bpd:
Figure A14.27
PCP
Calculate the head requirements
SEPTEMBER 2003
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162 - 164APPENDIX A – WORKED EXAMPLES
Figure A14.28
PCP
When the calculation is finished, select done and design; form this panel you will be able to
select the pump and rods, the more pumps there are in the database, the wider is the range
of choices.
Figure A14.29
PCP design
For this particular design and pump selection, if one wants to produce 800 bpd at downhole
conditions, 300 RPM of pump speed are required. Also the program will provide rod stress,
etc.
From the main screen select Calculation/ System (IPR+VLP) to perform nodal analysis
considering the pump, it is possible to see that now we will be able to lift 600 bpd:
PETROLEUM EXPERTS LTD
APPENDIX A – WORKED EXAMPLES163 - 164
Figure A14.30
PCP results
In Plot, choose the option Variables. Change the variables, selecting IPR, VLP and Pump
Discharge:
Figure A14.31
PCP results
This finishes the tutorial section.
SEPTEMBER 2003
PROSPER MANUAL
164 - 164APPENDIX A – WORKED EXAMPLES
A15 Files location
The PROSPER files for the above tutorials can be found from the following directory:
Tutorial
Tutorial 1
Tutorial 2
PROSPER file
OILWELL.*
OILVLP.*
GASLIFT.*
Tutorial 3
FLOWLINE.*
Tutorial 4
ENTHALPY.*
Tutorial 5
ESPWELL.*
Tutorial 6
HSPWELL.*
CONDEX.*
Tutorial 7
CONDEX2.*
CONDEX3.*
Tutorial 8
GRAVEL.*
Tutorial 9
HWELL.*
Tutorial 10
MLAYER.*
Tutorial 11
MULTILAT1.*
Tutorial 12
MULTILAT2.*
Tutorial 13
Tutorial 14
MULTILAT3.*
MULTILAT4-PCP.*
PETROLEUM EXPERTS LTD
File location
Sample sub-directory, under the
main Petroleum Experts directory
Appendix B References
B1 PVT Calculations
The following reference was used for the Glasø, Lasater, Standing and Vazquez-Beggs
correlations:
1.
Sutton, R.P. and Farshad, F.F.: ‘Evaluation of Empirically Derived PVT Properties
for Gulf of Mexico,’ SPE Reservoir Engineering, (Feb. 1990), 79-86.
2.
Beal, C.: ‘The Viscosity of Air, Water, Natural Gas, Crude Oil and its Associated
Gases at Oil Field Temperatures and Pressures,’ Trans., AIME (1946) 165, 94-98.
3.
Beggs, H.D. and Robinson, J.R.: ‘Estimating the Viscosity of Crude Oil Systems,’
JPT (Sept. 1975), 1140-1144.
4.
Carr, N.L., et al : ‘Viscosity of Hydrocarbon Gases Under Pressure,’ Trans., AIME
(1954), 264-268.
5.
Eilerts et al: ‘Phase Relations of Gas Condensate Fluids,’ Monograph 10, U.S.
Bureau of Mines, Washington D.C. (1957).
6.
Brinkman, F.H. and Sicking, J.N.: ‘Equilibrium Ratios for Reservoir Studies’, SPE
(Nov. 1959), SPE reprint series No. 15, 240-246.
7.
Katz, D.L. and Kurata, F.: ‘Retrograde Condensation’, Ind. Eng. Chem. (June,
1940) 32, No. 6, 817-827.
8.
Katz, D.L., Monroe, R.R. and Trainer, R.P.: ‘Surface Tension of Crude Oils
Containing Dissolved Gases,’ Trans., AIME (1943), 1624, 285-294.
9.
Lee et al: ‘The Viscosity of Natural Gases’, Trans., AIME (1966), 997-1002.
10.
Lohrenz et al: ‘Calculating Viscosities of Reservoir Fluids From Their
Compositions’, JPT (Oct. 1964), 1171-1176.
11.
Coats, K.H.: ‘An Equation of State Compositional Model’, paper SPE 8284
presented at SPE Annual Technical Conference and Exhibition, Las Vegas,
Nevada, Sept. 23-26, 1979.
12.
Nghiem, L.X., Fong, D.K. and Aziz, K.: ‘Compositional Modelling with an Equation
of State’, paper SPE 9306 presented at SPE Annual Technical Conference and
Exhibition, Dallas, Texas, Sept. 21-24, 1980.
13.
Winkler, H.W., Eads, P.T.: ‘Algorithm for More Accurately Predicting NitrogenCharged Gas-Lift Valve Operation at High Pressures and Temperatures’, paper
SPE 18871 presented at SPE Production Operations Symposium, Oklahoma City,
Oklahoma, March 13-14, 1988.
14.
Peng, D.-Y. and Robinson, D.B.: ‘A New Two-Constant Equation of State’, I.&E.C.
Fundamentals (1976) 15, No.1, 59-64.
2-5
APPENDIX B - REFERENCES
B2 IPR Calculations
1.
Dietz: ‘Determination of Average Reservoir Pressure From Build Up Surveys,’
Trans., AIME.(1965).
2.
Fetkovich M.J.: ‘The Isochronal Testing of Oil Wells,’ paper SPE 4529 presented
at the SPE 1973 Annual Fall Meeting, Las Vegas, Sept. 30-Oct. 3.
3.
Forcheimer et al: Zeits V. Dutching, (1901), 45, 1782-1786.
4.
Goode P.A. and Kuchuk F.J., ‘Inflow Performance of Horizontal Wells,’ SPE
Reservoir Engineering (Aug. 1991) 6, No. 3, 319-323.
5.
Jones L.G., Blount, E.M et al: ‘Use of Short Term Multiple Rate Flow Tests to
Predict Performance of Wells Having Turbulence,’ paper SPE 6133 presented at
the 1976 SPE Annual Technical Conference and Exhibition, New Orleans, Oct. 3-6.
6.
Vogel J.V.: ‘Inflow Performance Relationships for Solution Gas Drive Wells,’ JPT
(Jan. 1968), 83-92.
7.
Houzé, O.P., Horne, R. and Ramey, H.J. Jr.: ‘Infinite Conductivity Vertical Fracture
in a Reservoir with Double Porosity Behaviour’, paper SPE 12778 presented at
SPE Regional Meeting, Long Beach, California, April 11-13, 1984.
8.
Karakas, M. and Tariq, S.: ‘Semi-Analytical Productivity Models for Perforated
Completion’, paper SPE 18271 presented at SPE Annual Fall Technical
Conference and Exhibition, Houston, Texas, Oct. 2-5, 1988.
9.
Dikken, B.J.: ‘Pressure Drop in Horizontal Wells and its Effect on Their Production
Performance’, Journal of Petroleum Technology, November, 1990; Trans., AIME,
289.
10.
Chaperon, I.: ‘Theoretical Study of Coning Towards Horizontal and Vertical Wells
in Anisotropic Formations: Subcritical and Sub-Critical Rates’, Paper SPE 15377
presented at the 1986 SPE Annual Technical Conference and Exhibition, New
Orleans, Oct. 5-8.
11.
Goode, P.A. and Wilkinson, D.J., : ‘Inflow Performance of Partially Open
Horizontal Wells’, Paper SPE 19341 presented at the 1989 SPE Eastern Region
Meeting, Morgantown, WV, Oct. 24-27. Also Journal of Petroleum Technology,
August 1991, pp 983-985.
12.
Papazatacos, P., Herring, T.R., Martinsen, R. and Skjaeveland, S.M.: ‘Cone
Breakthrough Time for Horizontal Wells’, Paper SPE 19822 presented at the 64th
Annual Technical Conference, San Antonio, Texas, Oct. 8-11.
13.
Cinco-Ley, H., Samaniego, F. and Dominguez, N.: ‘Transient Pressure Behaviour
for a Well With a Finite-Conductivity Vertical Fracture’, Paper SPE 6014 presented
at the 51st Annual Technical Conference, New Orleans, Louisiana, Oct. 3-6, 1976.
14.
Mavor, M.J. and Cinco Ley, H: 'Transient Pressure Behaviour of Naturally
Fractured Reservoirs', Paper SPE 7977 presented at the California Regional
Meeting of the SPE, Ventura, California, April 1979
15.
Wong, D., Harrington, A. and Cinco Ley, H: 'Application of the Pressure
Derivative Function in th Pressure Transient testing of Fractured Wells', Paper SPE
PETROLEUM EXPERTS LTD
APPENDIX B - REFERENCES
3-5
13056 presented at the 59th annual Technical Conference, Houston, Texas, Sept.
16-19, 1984
16.
4-5
APPENDIX B - REFERENCES
B3 Multiphase Flow Calculations
1.
Anand, et al, ‘Predicting Thermal Conductivities of Formations from Other Known
Properties,’ JPT (Oct. 1980).
2.
Ashford, F.E, and Pierce, P.E.: ‘The Determination of Multiphase Pressure Drops
and Flow Capacities in Downhole Safety Valves (Storm Chokes)’, paper SPE 5161
presented at the 1974 SPE Annual Fall Meeting, Houston Oct. 6-9.
3.
Beggs, H.D. and Brill, J.P.: ‘A Study of Two Phase Flow in Inclined Pipe,’ JPT
(May 1973), 606-617.
4.
Churchill-Chu, ‘Correlating Equations for Laminar and Turbulent Free Convection
from a Horizontal Cylinder,’ International Journal Heat Mass Transfer (1975) 18,
1049-1053.
5.
Fancher, and Brown, G.G.: ‘Prediction of Pressure Gradients for Multiphase Flow
in Tubing,’ SPE Journal (Mar. 1963), 59-64.
6.
Fortunati, ‘Two Phase Flow Through Well-head Chokes,’ paper SPE 3742
presented at 1972 SPE European Spring Meeting, Amsterdam, May 17-18.
7.
Hagedorn, A.R. and Brown, K.E.: ‘Experimental Study of Pressure Gradients
Occurring During Continuous Two-Phase Flow in Small-Diameter Vertical
Conduits,’ JPT (Apr. 1965), 475-484.
8.
Mandhane et al, ‘A Flow Pattern Map for Gas-liquid Flow in Horizontal Pipes,’
International Journal Multiphase Flow, 1, 537-541.
9.
Moody, ‘Friction Factor for Pipe Flow,’ Trans., AIME (1944), 66, 671-675.
10.
Mukherjee, H. and Brill, J.P.: ‘Liquid Holdup Correlations for Inclined Two-Phase
Flow,’ JPT (May 1983), 1003-1008.
11.
Oranje, ‘Condensate Behaviour in Gas Pipeline is Predictable,’ Oil and Gas Journal
(July 1973), 39-43.
12.
Orkiszewski, ‘Predicting Two Phase Pressure Drop in Vertical Pipes,’ JPT (June
1967), 829-833.
13.
Duns, H. Jr and Ros, N.C.J.: ‘Vertical Flow of Gas and Liquid Mixtures in Wells,’
Proc., Sixth World Petroleum Congress, Frankfurt (1963) 451.
14.
Tansev, E. Startzman, R.A. and Cooper, A.M.: ‘Predicting Pressure Loss and
Heat Transfer in Geothermal Wellbores,’ paper SPE 5584 presented at the 1975
SPE Annual Fall Meeting, Dallas, Sept. 28-Oct. 1.
15.
Gould, T.L, Tek, M.R. and Katz, D.L.: ‘Two-Phase Flow Through Vertical, Inclined,
or Curved Pipe,’ JPT, August, 1974, 915-925.
PETROLEUM EXPERTS LTD
APPENDIX B - REFERENCES
5-5
B4 Temperature Calculations
1.
Chiu, K. and Thakur, S.C.: ‘Modeling of Wellbore Heat Losses in Directional Wells
Under Changing Injection Conditions,’ paper SPE 22870 presented at the 1991
SPE Annual Fall Meeting, Dallas, Oct. 9-9. pp 517 - 528.
2.
Hasan, A.R. and Kabir, C.S.: ‘Heat Transfer During Two-Phase Flow in
Wellbores: Part I - Formation Temperature,’ paper SPE 22866 presented at the
1991 SPE Annual Fall Meeting, Dallas, Oct. 9-9. pp 469 - 478.
3.
Hasan, A.R. and Kabir, C.S.: ‘Heat Transfer During Two-Phase Flow in
Wellbores: Part II - Wellbore Fluid Temperature,’ paper SPE 22948 presented at
the 1991 SPE Annual Fall Meeting, Dallas, Oct. 9-9. pp 695 - 708.
4.
Carslaw, H.S. and Jaeger, J.C.: ‘Conduction of Heat in Solids,’ Oxford Science
Publications, Oxford, U.K., 1959.
SEPTEMBER 2003
PROSPER MANUAL
Appendix C Equations
C1 Black Oil Model for Condensate
PSEP
TSEP
Total GOR is the total of separator and tank
GOR.
TANK
γgtot
Rtot = Rsep + Rtnk
Feed gas gravity ( γ gtot ) is the weighted
average of separator and tank gas gravities.
γ gsep
γ g tot =
γ gtnk
GOR tnk
GOR sep
(γ g sep Rsep + γ g tnk Rtnk )
Rtot
C1.1 Mass Balance Calculations
Based on the principles of mass balance the following equations can be derived.
Known Parameters:
Produced Gas Gravity
Condensate specific gravity
The condensate to gas ratio
Air Mol. Wt.
Water density
Air density @ SC
Mol.wt of condensate
γgt
ρc
CGR
28.966
62.43
0.0764
Mc
STB/SCF
lb/lb.mol
lb/cu.ft
lb/Scf
lb/lb.mol
Basis of calculations : 1 SCF of Produced gas.
The gas gravity of the mixture γ can be evaluated using the following equation
(
(
)
)
lb
MWmix
Total.Mass.of .mixture.entering  lb 
1
lb.mol =
×
γ =


28.966 lb
 lb  Total .moles.of .mixture.entering  lb.mol 
28.966
lb.mol

 lb.mol 
Total inlet mass calculation:
Mass of Produced gas =
Vol of gas @SC x Density of gas @SC
2 - 15 APPENDIX C - EQUATIONS
=
Vol of gas @SC x Gas gravity x Density of air @SC
=
 lb 
1(SCF ) × γ gt × 0.0764

 SCF 
=
0.0764γ gt (lb )
Mass of Condensate =
Â
Vol of Cond @SC x Density of Cond. @SC
=
Vol of Cond.@SC x sp.gravity x Density of water @SC
=
CGR(STB ) × 5.615
=
5.615 × 62.43 × ρ c × CGR(lb )
Thus, Total mixture mass =
 lb 
Cu. ft

× ρ c × 62.43
STB
 Cu. ft 
Mass of Produced gas + Mass of
Condensate
Mass.of .Mix = 0.0764 × γ gt + 5.615 × 62.43 × CGR × ρ c (lb )
Total inlet moles calculation:
Moles of Produced gas =
=
=
Mass of gas/ Mol.Wt.of gas
Mass of gas / Gas gravity x Mol.Wt. air
0.0764γ gt (lb )
 lb 

 lb.mol 
γ gt × 28.966
=
0.0764
(lb.mol )
28.966
=
Mass of Cond./ Mol.Wt.of Cond
Moles of Cond.
PETROLEUM EXPERTS LTD
APPENDIX C - EQUATIONS 3 - 15
=
=
Â
5.615 × 62.43 × ρ c × CGR(lb )
 lb 
Mc

 lb.mol 
5.615 × 62.43 × ρ c × CGR
(lb.mol )
Mc
Thus, total mixture moles = Moles of Produced gas + Moles of
Condensate
Moles of Mix =
0.0764 5.615 × 62.43 × CGR × ρ
(lb.mol )
+
28.966
Mc
Thus the gas gravity of the inlet mixture is
γ =
Total.Mass.of .mixture.entering  lb 
1
×


 lb  Total.moles.of .mixture.entering  lb.mol 
28.966

 lb.mol 


 0.0764 × γ gt + 5.615 × 62.43 × CGR × ρ c  lb 
1
=
×


lb.mol 
 lb   0.0764 + 5.615 × 62.43 × CGR × ρ c


28.966

M c 
 lb.mol   28.966
Â
4 - 15 APPENDIX C - EQUATIONS
C1.2 Using the mass balance results to define Condensate Model
Based on this formulation based on the seperator gas gravity and the average total gas
gravity, the effective CGR vaporised in separator gas is estimated as follows
CGRsep =
4588.3 ρ cond
γ g sep - γ g tot
- 132904 γ g sep ρ cond /M cond
Separator liquid/gas ratio ( CGRsep ) referred to separator liquid.
Also assuming that the condensate is above dew point, the initial CGR under reservoir
conditions is,
CGRres =
Rsep
1
+ Rtnk
Thus, the gas gravity under reservoir conditions can be found as
γ g res =
γ g tot + 4588.3 ρ cond CGRres
1 + 132904 ρ cond CGRres /M cond
γ
gsep
Rsep
P=Psep
T=Tsep
γ gres
γgtnk
Rtnk
ρcondsc
Cres
SEPARATOR
TANK
Thus, we can have two independent equations, which are
• At Reservoir conditions:
γ g res =
•
γ g t + 4588 ρ condsc CGRres
1 + 132904 ρ condsc CGRres /M cond
At Separator Conditions:
CGR sep =
4588.3 ρ csc
γ g sep - γ g tot
- 132904 γ g sep ρ condsc /M cond
NOTE:
γgt > γgsep ⇒ CGRsep negative
At and above Dew Point:
PETROLEUM EXPERTS LTD
APPENDIX C - EQUATIONS 5 - 15
CGRres =
Rsep
1
+ Rtnk
The CGR at pressures lower than dew point is estimated by a second degree polynomial as
shown
CGR = CGRmin + (CGRres
 P
f
− CGRmin )
−
P
 dewpoint 1 −


f 
2
where
f =
Pmin
Pdew
Pmin being the maximum liquid dropout pressure and a function of the dewpoint pressure.
i.e.
Pmin = F Pdewpoint
(
)
Pdew is an input to the model.
The vaporised CGR curve as a function of pressure looks as below:
comp
f is from maximum liquid dropout or mix
condensate in solution.
CGR = CGRmin + (CGRres - CGRmin ) *
f
P
Pdew
SEPTEMBER 2003
1
 P

-f

 Pdewpo int



1- f




2
PROSPER MANUAL
6 - 15 APPENDIX C - EQUATIONS
C1.3 Estimation of CGRmin
First calculate condensate mole fraction:
M cond
28.966
% Gas Mole Fraction =
M cond
γg28.966
7.08
f = 0.15 +
+ 1.45 * % Condensate
TRES - 161
Bg
CGRmin = CGRres - Lmax
561.5 Bo
γ g tot -
(From Eilerts et al)
Where Lmax is the maximum liquid dropout percentage.
Thus we need to estimate Bo and Bg to find CGRmin from the following equation
CGRmin
PETROLEUM EXPERTS LTD
=
CGR res − Lmax Bg
561.5 Bo
APPENDIX C - EQUATIONS 7 - 15
C2 Multiphase Pseudo Pressure
k
∂P 
q o = 2πrh o ∗ 
 µ o ∂r 
 k g ∂P 

q g = 2πrh
∗
µ

r
∂
 g

k
∂P 
q w = 2πrh w ∗ 
 µ w ∂r 
Total Mass Flow Rate:

kg
k
k  ∂P
+ ρw w 
mr = 2πrh ρ o o + ρ g
 µ
µg
µ w  ∂r
o

Change of Mass Flow Rate Across Annulus:
kg
k  ∂P 
∂m r
∂   k
= 2πh r  ρ o o + ρ g
+ ρ w w   ......................
∂r
∂r   µ o
µg
µ w  ∂r 
Change in Mass Flow Rate = Change in Density / Mass accumulation in Annulus
∂m r
∂ρ
= 2πrh φ
∂r
∂t
..............................................................
ρ = So ρ o + S g ρ g + S w ρ w
1 and 2 ⇒
kg
k  ∂P 
∂   k o
∂ρ
+ ρg
+ ρw w   = rφ
.......................
r  ρ o
∂r   µ o
µg
µ w  ∂r 
∂t
By Definition:
C =
1 ∂ ρ 

*
ρ  ∂P 
or
T
_
∂r
=ρc
∂P
C = S wC w + S o Co + S g C g
SEPTEMBER 2003
PROSPER MANUAL
8 - 15 APPENDIX C - EQUATIONS
Equation 3 becomes:
_
ρg
ρ  ∂P 
∂   ρ o
∂P
+ kg
+ kw w   = r φ ρ c
r  k o

∂r   µ o
µg
µ w  ∂r 
∂t
To Linearize this Equation:

ρg
ρ 
k
+ k w w ∂P
m( p ) = ∫  ρ o o + k g
 µ
µg
µ w 
o
0 
p

k g µo
k µ
k 
= ∫ o  ρo +
+ w o ρ w ∂P
ρ
g

µ o 
ko µ g
ko µ w
0

p
qg

q
k 
= ∫ o  ρ o +
ρ g + w ρ w ∂P
µo 
qo
qo

0
p
p
=∫
0
GORout B g

WORout Bw
ko 
 ρ o +
ρg +
ρ w ∂P
µo 
Bo
Bo

Combining we get:
∂ 
∂m( p )  rφ r c µ o ∂m( p)
∗
 r ko
=
∂r 
∂r 
F
∂t
Where
F = ρo +
⇒
GORout Bg
Bo
ρg +
WORout Bw
ρw
Bo
_
µ o ∂m( p)
∂ 2 m( p )
1 ∂m( p)
+
=
φ
c
2
r ∂r
Bo ∂t
∂r
So ρ o + S g ρ g + S w ρ w
C = c
F
For Condensates:
µ g ∂m( p)
∂ 2 m( p )
1 ∂m( p)
+
= φc
2
r ∂r
kg
∂t
∂r
C=c
Fg =
So ρo + S g ρg + Sw ρ w
Fg
Bo CGRout
B WGR
ρo + ρ g + w
ρw
Bg
Bg
PETROLEUM EXPERTS LTD
APPENDIX C - EQUATIONS 9 - 15
C3 Temperature Models
Enthalpy Balance temperature model in PROSPER applies the general energy equation for
flowing fluid:
 mv 2 
 mgz 
 + ∆
 + ∆( pV ) − Q = 0
∆U + ∆
 2g c 
 gc 
In terms of Enthalpy H = U + pV , this is written:
 mv 2 
 mgz 
 + ∆
 − Q = 0
∆H + ∆
 2g c 
 gc 
If heat transfer with the surroundings (Q) is neglected, the usual pressure equation solved in
multiphase flow results. PROSPER solves the general energy equation by considering the
enthalpy balance across an incremental length of pipe. The enthalpy term includes the
effects of pressure (including Joule-Thomson effect) and phase changes.
The algorithm commences by calculating the enthalpy at
the known pressure and temperature of the first
calculation node. i.e. H1 at (T1,P1)
For a given pipe increment, the enthalpy (H2) at the other
end of the pipe is estimated. The difference (H2-H1) is
compared to ∆H.
Where
∆H = -
∆Q
1V 2
+ ∆Lcosθ + tot
ρ l ql + ρ g qg
2 g
If previous calculations exist, then:
P2 = P1 − G∆L ; T2 = T1 −
to give the first estimate of H2
dt
∆L
dz
We now deal with a piece of tubing of pipe length ∆L,
P + P2
T +T
and P = 1
;
T= 1 2
2
2
The total heat transfer coefficient is estimated for the T,
P of the iteration step to calculate the heat exchanged.
Using the energy equation, we can find dh. If dh does
not equal H2-H1, the iteration continues until
convergence. The Enthalpy Balance method solves the
energy equation simultaneously for both temperature
and pressure. The solution temperature at the
downstream side of the pipe increment is therefore the
value of T2 when the iteration has converged.
SEPTEMBER 2003
PROSPER MANUAL
10 - 15APPENDIX C - EQUATIONS
The heat transfer coefficient is used to calculate dQ within the enthalpy balance iterations
and not the temperature.
The heat transfer coefficient is itself a function of the temperature of both the fluid and the
surroundings; therefore iteration is required to find both the heat transfer coefficient and the
enthalpy balance. The formation is a thermal sink at temperature Te. The temperature
profile near the wellbore is dependent upon producing time and the thermal diffusivity of the
formation. The heat diffusivity equation accounts for localised heating (or cooling) of the
formation by the well fluids.
For a pipe increment, the heat flow is calculated using:

 (T − T )
f
e

dQ = 2π 
1
 f (t ) +
 k
r U
to TO
 e
Where: T
f



 ∆L



− T is the temperature difference between the fluid and the formation at infinity.
e
k e is the effective thermal conductivity of the formation (including allowance
for well fluids in porous formations)
f (t ) is the solution of the heat diffusivity equation
The exact solution of heat diffusivity equation is:
1
4 ∞ − x 2u2
du
e
=
∫
0
f (t ) π 2
U ( J 2 (u) + Y 2 (u))
0
0
(Carslaw and Jaeger Page 336)
This integral poses numerical problems as u→0 and is slow. This equation is
evaluated for very early times only.
For intermediate times, PROSPER uses a fit of the TD vs tD generated using the
exact solution. At later times a logarithmic approximation is used:

αt 
f (t ) = 0.982 log  1 + 1.81
e
r 

n
Where thermal diffusivity α =
k
ρ Cp
This formulation approximates the exact solution with less than 1% error. (From Kwan-Chu
and Subash Thakur).
U TO is the overall heat transfer coefficient.
1
1
1
1
1
=
+ + +
U TO h f hc hr hco
The overall heat transfer coefficient takes into account forced convection inside the pipe and
free convection outside the pipe plus radiation and conduction.
PETROLEUM EXPERTS LTD
APPENDIX C - EQUATIONS 11 - 15
Heat transfer from the pipe is in three terms:
∆Q = 2π k ∆L
(T1 − T2 )
•
Conduction
•
Forced Convection
r 
log e  2 
 r1 
∆Q = 2π r2 h f ∆L ( T1 − T2 )
•
Free Convection
∆Q = 2π r1 (hc + h f ) ∆L ( T1 − T2 )
and Radiation
Now, let us examine the components of the overall heat loss coefficient individually:
hf
is due to forced convection inside the pipe
1
0.023 k Ren0.8 Pr 3
hf =
rti
Where k is the average conductivity.
k av = k gas (1 − holdup) + k liquid ( holdup)
Ren = mixture Reynolds number (depends on VLP correlation used)
Cpµ
Pr =
i.e. mixture Prandtl number
k
C p = CPgas (1 − holdup) + CPliquid (holdup)
In the annulus, the free convection term is:
1
0.049 (Gr Pr ) 3 Pr0.0074 k
hc =
r 
rto log e  ci 
 rto 
where:
Gr =
and
ρa =
(rci − rco ) 3 ρ 2a β g ( Tto − Tci )
1  ∂ρ 
β=−  
ρ  ∂T  P
µ a2
i.e. mixture Grashof number
mixture density
thermal expansion coefficient
The convection terms are themselves a function of temperature. Iteration is
therefore required to find the annulus temperature for the convection term and
determine the overall heat transfer coefficient
SEPTEMBER 2003
PROSPER MANUAL
12 - 15APPENDIX C - EQUATIONS
H2
The radiation term is given by:
σ (Tto2 + Tci2 ) (Tto + Tci )
hr =

1 rto  1
+ 
− 1
ε to rci  ε ci 
H1
rti
H1
rto
rci
P1 , T 1
where σ is the Stefan-Boltzman
constant and ε is emissivity.
rco
rcem
The Conduction Terms. An example is for the tubing, where:
r 
rto log e  to 
 rti 
hco =
ki
Similar expressions are used for each casing string and each term combined to find the total
conductivity term U .
TO
PETROLEUM EXPERTS LTD
APPENDIX C - EQUATIONS 13 - 15
C4 Default Thermal Properties Database
The data listed below is at standard conditions. Correlations are used to estimate thermal
properties at other temperatures and pressures.
C4.1 Dry Rock Properties
Sandstone
Shale
Limstone
Dolomite
Halite
Anhydrite
Gypsum
Lignite
Volcanics
Cp
Rock
BTU/lb/degF
0.183
0.224
0.202
0.219
0.219
0.265
0.259
0.3
0.2
Conductivity
BTU/hr/ft/degF
Specific
Gravity
1.06
0.7
0.54
1.0
2.8
0.75
0.75
2.0
1.6
2.64
2.4
2.71
2.87
2.17
2.96
2.32
1.5
2.65
C4.2 Rock In Situ Fluids
H2O (Low salinity)
Cp
BTU/lb/degF
1.0
Conductivity
BTU/hr/ft/degF
0.35
H2O (High salinity)
1.02
0.345
Heavy Oil
Medium Oil
Light Oil
Gas
1.04
0.49
0.5
0.26
0.34
0.083
0.0815
0.0215
The dry rock properties are modified to wet rock properties upon the porosity, permeability
and rock consistency.
C4.3 Downhole Equipment
Mild Steel Tubing
Conduction Heat
Transfer coefficient
BTU/ft/hr/degF
26
Emissivity
14 - 15APPENDIX C - EQUATIONS
C5 Rough Approximation Temperature Model
The ambient temperature at point x is:
Ta ( x ) = Ta1 − G2 ( x − L1 ) sin θ
which implies that the rate of change of temperature with depth
dT
UπD
T − Ta1 + G2 ( x − L1 ) sin θ
=−
& p
dx
mC
[
]
The fluid temperature at point x is then found from
T ( x ) = Ta1 − G2 ( x − L1 ) sin θ + G1 sin θ
WC p
UπD
+ (T1 − Ta1 ) − G2 sin θ
WC p
UπD
e
  UπD 

 ( x − L1 ) 
−  
  WC p 

Where:
Ta1 = Ambient temperature at L1
T1 = Fluid temperature at entry
T(x)
θ
= Fluid temperature at current location
= Deviation angle
m& = Fluid mass flow rate
Cp = Specific heat capacity
U
= Overall heat transfer coefficient referred to pipe inside diameter
D
= Pipe inside diameter
G = Geothermal gradient
W = Product of phase mass flow rates and heat capacities m& oCpo +
m& wCpw + m& gCpg
PETROLEUM EXPERTS LTD
APPENDIX C - EQUATIONS 15 - 15
C6 Choke Calculation
From Bernoulli:
1
1
P +
ρ V2 = P +
ρ V2
1
1
1
o
2
2 o 0
From Mass Conservation:
ρ AV =ρ A V
1 1 1
0 0 0
In the throat, the maximum velocity is the speed of sound. Under critical conditions, the
choke becomes independant of the downstream pressure and temperature.
P
1
P
o
n 
2  n + 1

V
1


0 
=  1 +  n - 1
2
 V 

ms 






λ ρ
g
V2 =
ms
λ
+ λ ρ
i i
g
g
+
ρ V2
g gs
λ
l
ρ V2
l ls
λ C
+ λ C
pl
g pg
λ C + λ C
l vl
g vg
l
n =
λ
q
g
=
q
l
g
+ q
λ
;
g
l
= 1 - λ
g
Vms : 2 phase sound velocity from FORTUNATI, Vms will be much lower than the velocity of
either phase. Critical conditions are reached at much lower velocities.
For a mono phase
C
p
V 2 = 144
g
C
r
P g
o
ρ
C7 Multi-Phase Flow Correlations
−
−
−
For deviated wells, the Beggs and Brill hold up correction is used.
To determine interfacial tension, the Parachor technique is used.
Petroleum Experts correlation uses the Gould et al Flow Map and for the various flow
regimes we use the following:
Bubble flow:
Wallis and Griffith
Slug flow:
Hagedorn and Brown
Transition:
Duns and Ros
Annular Mist flow:
Duns and Ros
SEPTEMBER 2003
PROSPER MANUAL
1-1
APPENDIX D – DIETZ SHAPE FACTORS
Appendix D Dietz Shape Factors
In bounded reservoirs
31.6
2
2.07
1
30.9
2
31.6
1
2.72
1
0.232
1
0.115
4
27.6
4
27.1
60°
4.86
1
4
3.39
21.9
1
3
1
22.6
1
2
1
3.13
1
0.607
2
1
5.38
4
2
1
2.36
1
5
0.111
2
12.9
3
4
0.098
In water-drive reservoirs
4.57
1
10.8
19.1
In reservoirs of unknown
production character
25
2
D
PETROLEUM EXPERTS LTD
Appendix E File Formats
E1 Introduction
This appendix contains examples of some file formats used by PROSPER. For further
details and advice regarding interfacing PROSPER with other applications, please contact
Petroleum Experts Limited customer support.
E2 External PVT Tables
PROSPER can directly import proprietary PVT table files generated by Petroleum Experts PVT
Package. The following file format description can be followed to re-format PVT tables
obtained from other sources.
* TEST EXAMPLE OF AN OIL PVT TABLE IMPORT FILE
* (BLANK LINES AND LINES WITH AN ASTERISK (*) IN COLUMN 1
* ARE IGNORED)
*
* UNITS for each data item are assumed to be whatever is the current
* setting at the time of import
* NUMBER OF TABLES
5
(MAX 10)
* DATA COLUMN IDENTIFIERS
* - CAN BE IN ANY ORDER
* - COLUMNS CAN BE MISSING
* - ANY INDIVIDUAL ITEM > 3.4e35 = missing item
*
*
* PRES - Pressure
* GOR - Gas-Oil Ratio]
* OFVF - oil
Formation Volume Factor
* OVIS - oil
Viscosity
* ODEN - oil
Density
* OCOM - oil
Compressibility
* GFVF - gas
Formation Volume Factor
* GVIS - gas
Viscosity
* WVIS - water Viscosity
* WCOM - water Compressibility
* ZFAC - Z Factor
* GDEN - gas density
* CGR - produced cgr
*
OFVF GOR OVIS ODEN PRES
*
*
*
*
*
*
*
*
*
TABLE IDENTIFIER RECORD
N LINES TEMP BP
N
LINES
TEMP
BP
-
Table Number
Number of lines in the table (max 15)
Table Temperature
Table Bubble Point Pressure (Dew Point for condensate)
1 3 100 1300
1.21 453 .99 46
1.31 454 .98 47
1.41 455 .97 49
2 3 200 1310
2.21 553 .89 56
2.31 554 .88 57
2.41 555 .87 59
3 3 300 1390
3.21 653 .79 76
3.31 654 .78 77
3.41 655 .77 79
6 3 400 1400
4.21 753 .69 86
4.31 754 .68 87
4.41 755 .67 89
2000
2010
2020
3000
3010
3020
4000
4010
4020
5000
5010
5020
2-7
8 3
5.21
5.31
5.41
APPENDIX E - FILE FORMATS
500
853
854
855
1800
.59 96
.58 97
.57 99
6000
6010
6020
* Note that the units used in PROSPER and the PVT table must be the same. Once the
tables have been read in, PROSPER’s Units system can be used to display the values in any
desired units.
PETROLEUM EXPERTS LTD
APPENDIX E – FILE FORMATS
3-7
E3 Lift Curves
The following is an example of a flowing well lift curve in ECLIPSE format:
-- VFP TABLE for PRODUCER -VFPPROD
1 10430 'LIQ' 'WCT' 'GOR' /
100 1000 10000 /
114.696 514.696 5014.7 /
0 0.5 0.9 /
0.8 1 5 /
0 /
1 1 1 1 2002.17 1258.71 2733.66 /
1 1 2 1 1479.42 1083.09 2655.25 /
1 1 3 1 413.537 806.953 4503.13 /
1 2 1 1 3948.98 2376.35 3439.27 /
1 2 2 1 3619.42 1985.43 3270.18 /
1 2 3 1 494.134 928.339 3352.16 /
1 3 1 1 4913.94 4485.14 4672.16 /
1 3 2 1 4895.27 4343.38 4563.92 /
1 3 3 1 3925.4 2141.93 3460.48 /
2 1 1 1 3629.53 2559.11 3358.56 /
2 1 2 1 3539.7 2209.16 3216.7 /
2 1 3 1 1098.95 1408.86 4038.35 /
2 2 1 1 4817.47 3863.58 4190.39 /
2 2 2 1 4746.81 3540.81 3985.01 /
2 2 3 1 1916.92 1594.64 3434.72 /
2 3 1 1 5347.77 5166.94 5283.46 /
2 3 2 1 5337.64 5102.83 5210.6 /
2 3 3 1 5138.74 3590 4155.85 /
3 1 1 1 8202.54 8206.84 8494.42 /
3 1 2 1 8081.09 8085.64 8397.43 /
3 1 3 1 7436.73 7142.24 8450.65 /
3 2 1 1 9393.27 9014.22 9196.49 /
3 2 2 1 9308.64 8911.21 9105.01 /
3 2 3 1 8567.24 7774.64 8436.27 /
3 3 1 1 9912.37 9798.83 9952.61 /
3 3 2 1 9906.65 9776.86 9924.11 /
3 3 3 1 9813.74 9404.22 9463.37 /
Gas Lifted Well (4 Variable) Lift Curves
-- VFP TABLE for PRODUCER -VFPPROD
1 10430 'LIQ' 'WCT' 'GOR' /
100 1000 10000 /
114.696 1014.7 /
0.5 0.9 /
0.82 5 /
0 0.2 0.5 /
1 1 1 1 4236.42 2633.35 3373.19 /
1 1 1 2 3825.95 2143.51 3274.85 /
1 1 1 3 3124.78 1852.12 3267.76 /
1 1 2 1 679.721 1006.21 3341.52 /
1 1 2 2 663.546 996.833 3405.81 /
1 1 2 3 641.284 977.228 3341.56 /
1 2 1 1 4983.68 4569.28 4613.82 /
1 2 1 2 4855.84 3445.19 4260.77 /
1 2 1 3 4234.42 2708.11 3888.35 /
1 2 2 1 4324.78 2288.63 3403.99 /
1 2 2 2 3770.29 1978.18 3361.59 /
1 2 2 3 2893.22 1811.06 3390.73 /
2 1 1 1 5416.3 4901.7 4903.34 /
2 1 1 2 5416.24 4900.79 4902.04 /
2 1 1 3 5416.15 4899.42 4900.17 /
2 1 2 1 4853.52 2622.82 3962.47 /
2 1 2 2 4853.36 2606.9 3962.25 /
2 1 2 3 4853.12 2591.41 3961.94 /
2 2 1 1 5925.14 5771.07 5819.76 /
2 2 1 2 5925.09 5770.6 5819.25 /
2 2 1 3 5925.01 5769.9 5818.5 /
2 2 2 1 5814.71 4954.63 4912.08 /
2 2 2 2 5814.64 4953.02 4911.18 /
2 2 2 3 5814.53 4950.61 4909.88 /
SEPTEMBER 2003
PROSPER MANUAL
4-7
APPENDIX E - FILE FORMATS
E4 IPR
*
* This is an example IPR input file
*
The format is pressure, rate, curve value
*
The numbers can be space, tab or comma delimited
* Up to twenty points per curve, up to five curves
*
*Blank lines or lines with an asterisk (*) in the first
* column are ingored.
*
0
1000
2000
3000
4000
5000
5000
4000
3000
2000
1000
0
1000
1000
1000
1000
1000
1000
*
* Next curve
*
0
3000 2000
1000 2000 2000
2000 1000 2000
3000
0 2000
E5 ESP PUMPS
*
*
*
*
*
Blank lines or lines begining with an asterisk are ignored.
The format for the pump data is
Line 1 Manufacturer pumpname size (ins) frequency(hz) Min. rte Max. rate No. of Stages
Line 2 six coefficients for head curve
(ft of water)
Line 3 six coefficients for power curve (HP)
* Curves are polynomials of the form
*
Y = AO + A1*x + A2*x*2 + A3*x**3 + A4*x**4 + A5*x**5
****************************
****************************
****************************
*** CENTRILIFT PUMPS
***
****************************
****************************
****************************
CENTRILIFT DC-800
3.38 60 550
950
*
A5
A4
A3
-1.695826E-14 3.474714E-11 -3.873426E-08
3.389608E-16 -6.347699E-13 1.397720E-10
1
A2
A1
8.776504E-06 -7.290256E-04
1.695927E-07 1.838891E-05
CENTRILIFT DC-1000
3.38 60
700
1300 1
0.0000000000 1.629606E-13 -3.038773E-09 -4.764406E-07 -2.538143E-03
-1.535787E-17 8.375897E-14 -1.485183E-10
4.492726E-08 1.474800E-04
PETROLEUM EXPERTS LTD
A0
2.06500E+01
9.70000E-02
2.05000E+01
8.501001E-02
APPENDIX E – FILE FORMATS
5-7
E6 ESP MOTORS
*Manufacturer
Reda
* Number of motors, rpm, frequency
2
3450.
60.0
*Series OD
456
4.56
*amps
6.53822E-01 -1.34128E+00 8.86349E-01 -1.06114E-01 5.61883E-01
*rpm
-6.24718E+01 2.04999E+02 -3.03911E+02 1.45552E+02 -1.15803E+02
*efficiency
-5.57129E-01 1.60591E+00 -7.30540E-01 -1.98693E+00 2.49918E+00
* power factor
-5.44220E-01 2.16557E+00 -2.81504E+00 7.11957E-01 1.04810E+00
3.43896E-01
*
3.58291E+03
*
1.91886E-03
*
2.49609E-01
*
2.26834E-01
*
3.58175E+03
*
4.17187E-01
*
2.75835E-01
*
*Series
OD
540
5.4
*amps
-2.16508E-01 6.79101E-01 -5.79651E-01 3.59379E-01 5.24583E-01
*rpm
-2.14557E+01 8.55182E+01 -1.66122E+02 9.44086E+01 -1.44510E+02
*efficiency
3.67150E-01 -1.64327E+00 3.01018E+00 -3.02514E+00 1.72215E+00
* power factor
4.64765E-01 -2.48102E+00 5.12024E+00 -5.23541E+00 2.71560E+00
*Series
456
456
456
456
456
456
456
456
456
456
456
Type
S
S
S
S
S
S
S
T
T
T
T
HP
VOLTS AMPS
100.0 1075
51
100.0 1355
46
100.0 2205
29
110.0 1190
60
120.0 1255
70
120.0 1295
59
120.0 2245
35
200.0 2710
46
220.0 2380
60
240.0 2250
70
240.0 2590
59
540
540
540
540
540
540
540
540
540
540
540
S
S
S
S
S
S
T
T
T
T
T
180.0
180.0
200.0
200.0
225.0
225.0
450.0
480.0
480.0
540.0
600.0
SEPTEMBER 2003
945
1945
1100
2140
1135
2235
2270
2475
3345
2835
3300
120
59
115
54
127
64
127
122
89
120
115
PROSPER MANUAL
6-7
APPENDIX E - FILE FORMATS
E7 ESP CABLES
* Cable Type
* Volt drop coefficient
#1 Copper
0.26
#2 Copper
0.33
#4 Copper
0.53
#6 Copper
0.84
#8 Copper
1.32
#10 Copper
2.08
#12 Copper
3.32
Maximum ampage
115
#1 Aluminium
0.33
#2 Aluminium
0.53
#4 Aluminium
0.84
#6 Aluminium
1.32
#8 Aluminium
2.08
#10 Aluminium
3.32
95
70
55
50
50
50
95
70
55
50
50
50
E8 HSP PUMPS
*
* H Y D R A U L I C
* =================
*
*
*
*
*
*
*
D R I V E
=========
D O W N H O L E
===============
P U M P S
=========
This is a sample pump import file. Blank lines or lines begining
with an asterisk are ignored. The format for the pump data is
Line 1 Manufacturer pumpname size (mm) reference Speed(rpm) Min.
operating rate Max. operating rate No. of stages Max no. of Stages Min
Speed Max Speed
Line 2 six coefficients for head curve
(ft of water)
(a0 to a5)
Line 3 six coefficients for power curve (HP)
(a0 to a5)
* This data is supplied FOR EXAMPLE PURPOSES ONLY
********** DO NOT USE FOR SYSTEM DESIGN
* Contact your pump supplier for current performance data
****************************
****************************
****************************
***
WEIR PUMPS
***
****************************
****************************
****************************
WEIR TPL115 118 11500
2000 12200 1 18 3825 11500
439.726
-0.0145605
1.7487e-7 -4.0609e-11
-1.2e-15
15.0445
0.00470131
-8.1656e-7
9.018e-11 -5.0595e-15
PETROLEUM EXPERTS LTD
6.7794e-20
9.7463e-20
APPENDIX E – FILE FORMATS
7-7
E9 HSP TURBINES
Turbine Manufacturer
WEIR
* Number of Turbines
1
****************
*
*
*
WEIR T30
*
*
*
****************
* Turbine Type
T30
* Reference Speed
15000.0
(rpm)
* Maximum Speed
15000.0
(rpm)
* Maximum Test Pressure
8910.00
(psi)
* Maximum Working Pressure
5940.00
(psi)
* Maximum Stage Pressure
370.00
(psi)
* Maximum Number Of Stages
50
* Maximum Turbine Supply Flow
3911.67
(bbl/day)
* Maximum Total Shaft Torque
843
(lb.ins)
* Maximum Stage Torque
128
(lb.ins)
* Turbine Casing OD
3.46
(inches)
* Max. Velocity Over Turbine Casing
25.000
(ft/sec)
* Number of Settings
4
* Setting should be an alphanumeric string with NO embedded spaces (up to 8 characters)
* Setting
*
*
A
B
C
D
Efficiency
(percent)
52.750
56.000
60.460
64.000
SEPTEMBER 2003
Mininum Maximum
Rate
Rate
(bbl/day) (bbl/day)
1235.26
1523.49
1873.48
2367.59
2038.18
2460.23
3232.27
3788.14
Head
(a1)
Head
(a2)
Head
(a3)
0.000311733
0.000146428
0.000116043
6.97987e-5
-0.53145
-0.163852
-0.281785
-0.150449
447.209
184.132
395.769
243.193
Power
(a1)
2.2765e-6
1.6612e-6
1.8284e-6
2.0903e-6
Power
(a2)
-0.00245738
-0.00126675
-0.0037038
-0.00670166
Power
(a3)
0.551433
-0.431372
2.46547
7.15005
PROSPER MANUAL