Drops Technology AS

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Integration of 3D-shared earth model
with Drops Drilling Simulator to
reduce drilling costs
NFR project 150496/210
Presented in Stavanger 4 April 2003
Presented by
Runar Nygård, Drops Technology AS
© Drops Technology AS
Outline of presentation
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Project description
What is drilling optimization?
DDS – Drops Drilling Simulator-Technical description
Results so far
Summary
© Drops Technology AS
Project participants
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Drops Technology AS
Drops Technology AS was founded in 1997. It is a limited
company incorporated in Oslo, Norway
DROPS Technology AS sells services, program licenses and user
access, based on DROPS’ drilling optimization simulator DDS
2.7
PGS-Tigress
PGS-Tigress is 100% subsidiary of PGS
PGS-Tigress is a software company for the Exploration and
Production professionals with a suite of integrated tools
The main product being TIGRESS (The Integrated Geoscience
and Reservoir Engineering Software System).
© Drops Technology AS
Project description
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Today the Drops Drilling Simulator needs drilling data as
reference to build the physical drillability needed for the
simulator to simulate drilling.
This project will extend the drilling simulation capabilities so
other data from logs and seismic attributes from a shared 3D
earth model can be used as basis for drilling simulations.
Using such information would also give better prediction of
drillability variations related to different well paths.
GOALS
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Implement DDS in Tigress shared earth model software
Develop new models for drillability based on other type of data
than drilling data
Develop automatic well planning routine in Drops Drilling simulator
© Drops Technology AS
Tigress
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Integrated software for all
disciplines in petroleum
exploration
PC version is Linux based
Powerful database (PDR)
Open link to other software
(data loading)
© Drops Technology AS
Drilling optimization:
Simulation tools
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Today’s oil and gas industry utilize simulators mainly in three
of the four main operational engineering disciplines
Reservoir, production and formation evaluation all use
simulation tools to better evaluate different scenarios and to
improve interpolation and economics
In advance the production, reservoir and seismic/log analysis
can be performed
Drilling Engineering has a lack in planning tools available for
the actual drilling process
Drilling software is mainly related to the fluid system and wellrock interaction (well integrity)
© Drops Technology AS
Drilling optimization: Learning Curve
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The Learning
Curve has been
slow and
expensive.
Even after 30-40 wells have been drilled in the same formations
in a field there are still many combinations of bits and operating
conditions that have not been tried
Therefore you might not have reached the lowest drilling cost
Utilizing a simulator that can simulate these combinations in a
short period of time after the first well has been drilled, is
definitely a strong tool
© Drops Technology AS
Drilling optimization: Cost equation
Cf
(t


r
 tc  tt ) R$   Cbit   other
Footage
Required
inputs are actual bit costs, rig rate, and other costs
The simulator calculates rotating time (from ROP), connection
time and trip time
The individual bit run cost pr. meter and the cumulative cost pr.
meter are used to evaluate the optimum in terms of economics
Other costs, like: MWD/LWD, DD, down hole equipment, fluids,
personnel, boats and other
© Drops Technology AS
The Drilling Optimization Simulator
simple overview
An
earlier drilled well well is the reference
The simulator iterate a perfect match from the
reference “drillbehind”. Output from this is a strength
log, ARSL
This strength log is used as basis for the next well
Adjusted for lithology (formation thickness) and
survey, the new well can be optimized
© Drops Technology AS
Technical Approach
ROP , RPM , lith, bittype, wear, hydraulic , ( MW  pp)
ARSL 
ROP
 Predictive
ROP models have been developed in the past two decades
 ROP models exist for Rollercone, PDC and NDB/Geoset bits
 Describe the physical interaction between the bit and the rock as a
function of the parameters that effect the bit performance.
 Different bits have different cutting mechanisms.
 The cutting mechanism is integrated over the entire bit face and
converted to ROP in meter/hr.
 As the bit penetrates through the different formations the bit wears,
which again effect the ROP.
 The ROP models use unconfined rock strength as an input
 The ROP models can be used to predict unconfined rock strength if ROP
is known.
 The models have been verified in the laboratory and field
© Drops Technology AS

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3
2
2
ROP  W  fc  Pe   aS D
/ RPM  WOB  b / RPM  D
 cD / I m
f
bit
bit
bit
i ) Impact Force
I
f
 0.000516    q  vn
ii ) Modified Impact Force

Im  1  
0.122
 I f
iii ) Chip hold - down function


fc  P  cc  ac  P  120
e
e
iv ) Change in bit tooth wear
b
BG  Wc  WOBi  RPM  Ar  Si
v) Bit wear
W  1   ΔBG/8 
f
where,
ROP  rate of penetration
f P  chip hold down function
c e
W  wear function
f
a  bit coefficient
a  chip hold down coefficient
c
b  chip hold down coefficient
c
c  chip hold down coefficient
c
D  bit diameter, inches
bit
WOB - Weight on bit, klbs
c  bit coefficient
b  bit coefficient
S  confined rock strength, psi
RPM - rotational speed
 - mud plastic viscosity, cp
 - mud weight, ppg
I m - modified impact force
© Drops Technology AS

1
Apparent Rock Strength Log (ARSL)
Creation Procedure
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Each Bit-/BHA run is treated separately
Simulations are performed for each bit with different
ROP models dependent on bit type
“Apparent rock strength” is calculated based on an
initially assumed bit wear coefficient
A new wear coefficient is then estimated and a
multiple solutions iteration procedure for the entire
bit run is performed until the calculated bit wear
equals the actual bit wear
The resulting “apparent rock strength” log is now
specific for the formations in this area
© Drops Technology AS
DROPS Drilling Optimization
Simulator
DROPS Drilling Simulator Functionality
$/ft
Cum. $/ft
Operating
Parameters
Flowrate
Mud Wt.
Rheology
WOB
RPM
Jets
DROPS Drilling Simulator
ROP
Bit
Parameters
Bit Type
Tricone
PDC
NDB
Bit Design
Bit Wear
# Cutters
Cutter Info.
© Drops Technology AS
Optimum
Drilling - $
Formation
Model
ARSL
Rock St.
Pore Pr.
Survey
Rock DB.
Abrasiven.
% Lithology
Needed input data for ARSL creation
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Drilling, mudlogger and bit data needed
Drilling data - Depth, ROP, WOB, RPM, Flowrate, Plastic
Viscosity, Mud Weight
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Mudlogger data - Formation thickness Percent lithologies,
Pore Pressure
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Bit Data- Size, Type, Jets, Number of cutters and blades,
Backrake, Siderake, PDC layer thickness, Backup Cutters Info.,
Depth In, Depth Out, Wear In, Wear Out, TFA and POA.
© Drops Technology AS
Drops Drilling Simulator DDS
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Currently used in planning, follow up and post analysis of wells
DDS is a Windows based application and the interface is user
friendly, just “point and click”
© Drops Technology AS
Drops Drilling Simulator DDS
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Control sheet window
Cost is re-calculated based on every simulated change
© Drops Technology AS
Drops Drilling Simulator: The ARSL
Apparent Rock Strength
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Existing drilling data is used to calculate
a ARSL (Apparent Rock Strength Log)
The ARSL is used to plan and simulate
the forthcoming wells in the field
Assumption is that the drillability
properties for each formation does not
change from well to well
The simulator does not take into
consideration any 3D-effects like
anisotropy in stress field or mechanical
data
Up to now there has been time
consuming to simulate numerous
different well trajectories
20
30
40
50
60
Well A
800
Well B
Well C
900
1000
1100
1200
1300
1400
1500
1600
1700
1800
1900
2000
2100
© Drops Technology AS
10
700
Depth [mTVD]
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0
Learning Curve for One Bit
Learning Curve for 12.25 Section Using One Bit.
Total Cost for 12.25 Section, $
1800000
1700000
Bit A
Bit B
Bit C
1600000
1500000
1400000
1300000
1200000
1100000
1000000
900000
800000
Number of Simulations.
© Drops Technology AS
Bit D.
Bit E
Learning Curve Multiple Bits
Learning Curve for 12.25 Section Using Multiple Bits.
Bit B
Bit C
Bit B
Bit E
Bit C
Bit A
Bit C
Bit D
Bit C
Bit D
Bit D
Bit C
1300000
2 X Bit D
Bit A
Bit D
Bit B
Bit D
Bit B
Bit A
1400000
Bit A
Bit A
Bit A
Bit B
Total Cost for 12.25 Section, $
1500000
1200000
1100000
1000000
900000
800000
0
20
40
60
80Number of100
120
Simulations.
© Drops Technology AS
140
160
180
200
Simulator results: ROP
Measured and Calculated ROP vs depth
50
45
Measured ROP
40
Calculated ROP
ROP, m/h .
35
30
25
20
15
10
5
0
3650
3700
3750
3800
3850
Depth, mTVD
© Drops Technology AS
3900
3950
4000
Simulator Results: Rotating Hours
Cumulative rotating time for 12.25 inch Lyng bit
.
40.00
Measured rotating time
Cumulative rotating time (hours)
35.00
Calculated rotating time
30.00
25.00
20.00
15.00
10.00
5.00
0.00
2800
3000
3200
3400
TVD (m)
© Drops Technology AS
3600
3800
Simulation of Bit wear
(Reported
Wear 2-6)
8
Center
7
Bit Wear
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6
Bit Wear Evaluation
Gage
Average
5
4
3
2
1
0
2854 3000 3050 3100 3150 3200 3250 3300 3350 3400 3450 3500 3550 3600 3650 3688
TVD (m)
© Drops Technology AS
Drops Drilling Simulator: Real time
Follow up
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In addition to being a planning
tool, DDS has functionality for
comparing the planned well
program with the actual data from
the rig
Conduct rapidly decisions in
unforeseen situations
Re-simulate the planned program
with new equipment, bits, etc.
Time Progress, 12.25" Section
2050
Rotating Time, Simulated
2100
Rotating Time, Field
2150
2200
2250
2300
2350
2400
Depth [mMD]
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2450
2500
2550
2600
2650
2700
2750
2800
2850
2900
0
5
10
15
Time [Hr]
© Drops Technology AS
20
25
30
Software integration
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Task 1
Implement DDS in Tigress shared earth model software
This has been done by running Drops using vm-ware in Linux
All data needed for running DDS is stored in PDS.
Vector based special bit information is implemented in Tigress
as an drilling event
Adjusting data for DDS based on new well trajectories is easily
done in Tigress by using their G&G modules
DDS 2.7 is now commercially for sale by Tigress
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This task of the project is finished as planned
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© Drops Technology AS
Results: Software integration
© Drops Technology AS
Software integration
© Drops Technology AS
Software integration
© Drops Technology AS
Software integration
© Drops Technology AS
ARSL based on other strength criteria
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When bit is penetrating the rock, different modes of failure occurs
in the rock like, shearing, crushing and tension fracturing
The drillability is the resistance of the rock being penetrated by
the drill bits
Drillability of the rock is a dynamic parameter
However, Rock strength and drillability are closely connected
In this ongoing work we have been able to establish rock strength
based on different electric logs which is comparable with the ARSL
based on drilling data.
One exception is for harder zones which still some additional work
remaining
© Drops Technology AS
ARSL: From other sources
© Drops Technology AS
Variation in properties: Anisotropy
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Anisotropy effects
Stress field
Rock strength may have
anisotropic behavior
Or large variations
Effect when drilling:
If directional change determine
an increase in mudweight this
will increase drilling time and
increase wear
© Drops Technology AS
Task 3 progress report
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Task 3.
Develop automatic well planning routine in DDS
By developing algorithms that make more of the drilling
simulation automatically there is a possibility to increase the
numbers of well scenario which is simulated
A new bit routine is underway. This routine will make it possible
to automatically simulate different bits for each section and
thereby increase the numbers of simulations performed and
increase the value of planning
© Drops Technology AS
Summary
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Up to now our project followed its original progress
Task one, the software integration went well
Drops believe that being part of a larger software package to
the oil companies will give economical results in near future
We believe that drilling simulation will be common in the future
so the time works for us, not against us
We would like to thank NFR for giving a small company as ours
the possibility to do research. Whiteout NFR support we would
not have been able to do it
© Drops Technology AS
Example: Day to day follow up
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8 1/2” Section Time-Depth Curve
3500
8.5 in Pilot
Measured Depth (m)
3600
8.5in Simulated
RPM recommendations not followed
3700
8.5in Actual
3800
3900
4000
Rig was informed
that bit will wear out
before TD
4100
4200
Trying to save five
hours resulted in a
loss of 15+ hours
(or about $100.000) !
Trip for Bit Change
4300
Bit Quits Drilling
4400
0
5
10
15
20
25
30
Time (hrs)
© Drops Technology AS
35
40
45
50
55
60
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