Seismic to Geological Modeling Workflow, an Integrated Approach to Determine the Reservoir Quality of a
Natural Fractured Limestone Reservoir: Oseil Field Example*
Arie Krisna Lopulisa1, Roy Andrianto1, and Anggoro S. Dradjat1
Search and Discovery Article #20144 (2012) **
Posted May 14, 2012
*Adapted from oral presentation given in Bali, Indonesia at the Geoscience Technology Workshop (GTW) on Reservoir Quality of a Fractured Limestone Reservoir, 1517 February 2012
**AAPG©2012 Serial rights given by author. For all other rights contact author directly.
1
CITIC Seram Energy Ltd (randrianto@citicseram.com)
General Comments
Oseil field, on the island of Seram, eastern Indonesia, is used as the example to apply an integrated approach to determine the quality of a
naturally fractured limestone reservoir. Field data include:
Discovery date
1998
Type hydrocarbon
heavy oil
Reservoir type
fractured limestone
Limestone type
oolitic, mudstone/wackestone-grainstone
Age and name of reservoir Jurassic Manuseal Formation
The following is the conclusion resulting from following the workflow associated with this approach:
 Integration of well and seismic data provides better comprehensive understanding.
 The result of seismic fracture intensity is aligned with the well.
 Total loss circulation during drilling correlates with the intensity of fractures.
 Seismic attributes should constantly be utilized to identify anomalies.
 More effort is needed to incorporate mud loss and drilling parameter into the update model.
CITIC Seram Energy Limited
Seismic to Geological Modeling Workflow,
an Integrated Approach to Determine the Reservoir Quality
of a Natural Fractured Limestone Reservoir:
Oseil Field Example
Arie Krisna Lopulisa
Roy Andrianto
Anggoro S Dradjat
CITIC Seram Energy Ltd
15-17 Feb 2012
Bali Indonesia
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
CITIC Seram Energy Limited
Agenda
• Introduction
• Background
• Workflow
1.
2.
3.
4.
5.
6.
Fracture Analysis
Seismic Anisotropy
Geological Modeling
Discrete Fracture Network
Well Placement
Seismic Attribute
• Conclusion
15-17 Feb 2012
Bali Indonesia
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
CITIC Seram Energy Limited
Introduction
Regional Geology
Post-Thrust
Syn-Thrust
1
Pre-Thrust
3
Sandstone & Mudstone
2
Sub-Foreland Basin
Salas Complex
☆☆ ☆ ☆
Dominantly
Sandstone & Mudstone
+
Carbonate
Dominantly Carbonate
Shale
Uplift
Compression/Uplift
Extension/Transtensional
Reactivation
☆☆ ☆☆
Upper:Carbonate(Massive)
Compression/Uplift
Lower:Sandstone & Mudstone Listric Reactivation
Intra-Craton/Rifting
Sandstone & Mudstone
Incipient Rifting
Basement
(Metamorphic)
15-17 Feb 2012
Bali Indonesia
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
CITIC Seram Energy Limited
Introduction
Oseil Field Depth Structure Map
General Info :
Oseil 2 field
• Discovery of Oseil : 1998
Oseil 1/4 field
• First Oil : Dec 2002
NUB
Prospect
• Hydrocarbon Produced : Heavy Oil
• Reservoir type : Fractured Carbonate
Oseil Selatan
Prospect
• Formation name : Manusela Fm
• Age : Jurassic
NUA field
East Nief
Prospect
15-17 Feb 2012
Bali Indonesia
• Limestone type : oolitic limestone,
mudstone/wackestone - grainstone
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
CITIC Seram Energy Limited
Background
Main Challenges in Oseil Field
• High Heterogeneity Reservoir
• Fast & Severe Water Break-through
• Complex Fracture System
• Time Depth Conversion
• Drilling / operation challenges (total loss)
• Remote areas - high operating cost
15-17 Feb 2012
Bali Indonesia
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
CITIC Seram Energy Limited
Background
Study Purpose
• Better understanding of the Reservoir
• Increase accuracy in Well Placement
• Increase Production
15-17 Feb 2012
Bali Indonesia
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
CITIC Seram Energy Limited
Workflow
Seismic Anisotropy for
Fracture detection
Geological Modeling
Well based
Fracture Analysis
Volumetric
Discrete Fracture Network
Well Placement
Simulation
Oseil 2 field
Oseil 1/4 field
NUB
Prospect
Oseil Selatan
Prospect
15-17
Feb 2012
NUA field
Limitation
of
data
Bali Indonesia
availability
East Nief
Prospect
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
CITIC Seram Energy Limited
Workflow – Well Based Fracture Analysis
Fracture Analysis
15-17 Feb 2012
Bali Indonesia
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
CITIC Seram Energy Limited
Workflow – Well Based Fracture Analysis
Fracture Analysis based on core data
Oseil 2 field
Oseil 1/4 field
NUB
Prospect
Oseil Selatan
Prospect
Core photographs well OS-2 of Manusela Formation
15-17 Feb 2012
NUA field
Bali Indonesia
Close-up whole core photographs well NUA-3
of Manusela Formation
AAPG-EAGE Joint GTW on
East Nief
Prospect
Fractured Carbonate Reservoir
CITIC Seram Energy Limited
Seismic Anisotropy for Fracture Detection
Workflow – Seismic Anisotropy
Fracture Intensity Wells Vs Seismic
The correlation of fracture intensity between the 3 exploration wells
and the seismic inversion result shows a good match
15-17 Feb 2012
Bali Indonesia
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
CITIC Seram Energy Limited
Workflow – Geological & Fracture Modeling
Geological & Fracture Modeling of Oseil field
• High-quality static reservoir model is required to perform simulations in
order to predict the fluid dynamic
• A 3D reservoir model enables us to integrate multidata (well data, seismic
data, conceptual models, production data) for a more reliable result
• Ability to generate and simulate a dual-poro dual-perm reservoir behavior
15-17 Feb 2012
Bali Indonesia
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
CITIC Seram Energy Limited
Workflow – Geological & Fracture Modeling
Geological & Fracture Modeling of Oseil field
Geological Modeling
Volumetric
15-17 Feb 2012
Bali Indonesia
Fracture Modeling
Simulation
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
CITIC Seram Energy Limited
Workflow – Geological & Fracture Modeling
Example : Matrix Porosity Modeling Result
POR Histogram
Blue = 3D Model
Green = Upscaled Well-logs
Red = Raw Log
Variogram Analysis
Major Dir
: 133
Minor Dir
: 0.1097
Major Range : 4985
Minor Range : 928.2
Vert. Range : 38.7
Nuget : 0.225
15-17 Feb 2012
Bali Indonesia
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
CITIC Seram Energy Limited
Workflow – Geological & Fracture Modeling
Fracture Modeling
Fracture Interpretation
Based on image log & core data
(Fracture Orientation, Geometry, etc)
Fracture Analysis
Fracture Intensity Cube result--to
control Fracture Distribution
Model Parameters
Discrete Fracture Network
Upscale
DPDP Simulation
15-17 Feb 2012
Bali Indonesia
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
CITIC Seram Energy Limited
Workflow – Geological & Fracture Modeling
Input for Model Parameter
Model parameters are the object that
controls the intensity of the fracture,
called fracture drivers.
Main input for the
fracture distribution
Main input for the area
extension of the fracture
• Lithological/Facies drivers
• Seismic drivers
• Mechanical drivers
15-17 Feb 2012
Bali Indonesia
Distance to Fault Model
Zonation Model
Fracture Intensity Seismic
Area Segment Model
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
CITIC Seram Energy Limited
Workflow – Geological & Fracture Modeling
Discrete Fracture Network
• A fracture network is a group of planes representing fractures.
DFN Aperture Statistics
Min : 0.04 mm
Max : 4.5 mm
Mean : 1.24 mm
DFN Result of Zone 1
Distribution Method :
Use the Intensity from distance to
fault and seismic fracture intensity
Geometry :
Fracture Aperture, QC with the
data from image log & core data
Orientation :
Main trend of azimuth/dip should be
inline with the fracture from well
DFN Result of Zone 2
15-17 Feb 2012
Bali Indonesia
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
CITIC Seram Energy Limited
Workflow
The Well Placement in Oseil Field
• Undrained area
• The distance from oil-water contact and target zone in upper part of
Manusela fm
• Fracture intensity
• Interference well analysis
• Avoid the fracture directly connected to aquifer zone
• Horizontal length
15-17 Feb 2012
Bali Indonesia
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
CITIC Seram Energy Limited
Workflow – Well Placement
Well Placement Results
• 4 new development wells were proposed & designed based on this
integrated study
• The positive economic results shown from these 4 wells. The most
successful well (Os-2 ST2) and Os-16 well with < 0.5% water cut.
15-17 Feb 2012
Bali Indonesia
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
CITIC Seram Energy Limited
Os-2ST2
Undrained Area
Oseil-2 Area Saturation Distribution
N
Undrained Area (tendency of drainage area
is to follow the direction
and dip (relatively
vertical) of fracture
N
Os-2ST2
Os-2ST
Os-11
Os-10
Os-13
OS-2 ST2 INITIAL WELL CLEAN UP AND TEST
DAILY AVERAGE
1400
140
WC
MSCFD
1200
120
1000
100
800
80
600
60
400
40
200
20
0
28-Mar-11
0
4-Apr-11
11-Apr-11
15-17 Feb 2012
Bali Indonesia
18-Apr-11
25-Apr-11
2-May-11
9-May-11
16-May-11
23-May-11
WATER CUT (%) - GAS PRODUCTION (MSCFD)
OIL PRODUCTION (BOPD)
BOPD
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
CITIC Seram Energy Limited
Os-16
Undrained Area
Undrained Area (tendency of drainage area
is to follow the direction
and dip (relatively
vertical) of fracture
N
Os-16
Os-2ST2
Os-2ST
Os-11
Os-10
Os-13
OS-16 Initial Well Test (ESP) - Daily Average
BOPD
MCFD
WC
500
100
450
90
400
80
350
70
300
250
50
200
40
150
30
100
20
50
10
0
11-Dec-11
15-17 Feb 2012
Bali Indonesia
60
17 Dec. 2011: ESP tripped by O/C
18-Dec-11
25-Dec-11
1-Jan-12
8-Jan-12
15-Jan-12
22-Jan-12
29-Jan-12
0
5-Feb-12
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
WC (%)
Oil Production (BOPD) - Gas Production (Mcfd)
9 Jan. 2012: ESP back online
CITIC Seram Energy Limited
Avoid the fracture directly connected to aquifer zone
Well with early water break-through
OS-9
OS-18
• New well with TD shallower--60
ft--than nearby well
• Both penetrate the high
intensity fracture zone with total
loss encountered at bottom of
the well
TVDSS
5251’ SS
• New well suffers early water
breakthrough with water-cut
reaching 95%
5300’ SS
TD=7232’ MD / 5366’ SS
TD=7476’ MD / 5424’ SS
The distance between Os-9 and Os-18 : 300m
15-17 Feb 2012
Bali Indonesia
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
Workflow – Seismic Attribute
Ant-Track result-- Avoid the fracture directly connected to aquifer zone
Oseil-18
GR
TGas
C1
C2
C3
iC4
nC4
iC5
nC5
ROP
7032’ MD / 5300’ SS
7066’MD/5314’SS
(OH Packer)
Equivalent Depth with Os-9 (Top Manusela)-5319’ SS
7107’MD/5330’SS
(end of Tail pipe)
7152’MD/5345’SS
(Max. Top of
Cement)
Big fracture/fault zone??
Less Permeable
Excellent
Permeable
TD=7232’ MD / 5365’ SS
Oseil 18 - Daily Average
Well Test - Before & After Cement Plug
2250
500
Pi
450
2116
Oil 2000
400
Cement Plugging (Mar26-Apr16,2011)
Before cmt plug : 1035 BFPD, 95% WC, PI 48
Pi (PSI) / WC x 10 (%)
1750
After cmt plug : 305 BFPD, 18% WC, PI 4
1500
1250
WC
1000
750
350
300
250
200
150
500
100
250
50
BOPD
0
7-Oct 6-Nov 6-Dec
0
5-Jan
4-Feb 6-Mar 5-Apr 5-May 4-Jun
4-Jul
3-Aug 2-Sep
BOPD
2416 2500
Gas
Potential Source
of Channeling
Water
CITIC Seram Energy Limited
Conclusion
• Integration of well & seismic data provides better comprehensive understanding
• The result of seismic fracture intensity is aligned with the well
• Total loss circulation during drilling correlates with the intensity of fractures
• Seismic attributes should constantly be utilized to identify anomalies
• Need more effort to incorporate mud loss and drilling parameter into the update
model
15-17 Feb 2012
Bali Indonesia
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
CITIC Seram Energy Limited
Questions
15-17 Feb 2012
Bali Indonesia
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir
CITIC Seram Energy Limited
Thank You
15-17 Feb 2012
Bali Indonesia
AAPG-EAGE Joint GTW on
Fractured Carbonate Reservoir