Various types of computer simulation models are presented for evaluating Shale Gas development.

1. Shale Gas
Computer Simulation Models
Prepared by
Source Rock Engineering
26 May, 2010
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2. Computer Simulation
• Most comprehensive tool for evaluating the different
factors that influence gas reserves and production rates
• Applied for several decades by the petroleum industry
to evaluate a wide range of very large to very small
development projects
• Forecast accuracy depends on the quality and quantity
of data that define the gas resource.
• Calculations honor the physical laws of nature and so
the calculated results can not be unrealistic, unless
unrealistic assumptions are input in the model.
• Simulation results are now accepted for reserve
certification
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3. Applications
• Size of initial or remaining gas resource
• Correlating historical well performance to geologic or
timing factors.
• Prioritizing or evaluating future well locations and
different completion methods
• Forecasting production for revenue forecasts and for
surface facility designs
• Identifying optimum well spacing
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4. Simulation Software: Roxar MORE™
• Originally GCOMP from Amoco Research
• Now being maintained in Oxford, England
• Runs in Windows environment
• Relatively inexpensive but robust
• Capable of exporting files to other simulation software
packages
• Roughly 6 years of Source Rock Engineering
experience running this software for unconventional
gas
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5. Simulation – Model Types
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6. Common Model Types and Applications
• Single Well
• Evaluate different Completion or Drill Designs
• Forecast gas rates and recoveries
• Use the single-well forecast, along with the estimated drilling
schedule, to develop a multiple-well production forecast.
• Multiple Well
• Evaluate a portion of a Lease Area or Field
• Test different well spacings and development schedules
• Calculate which well locations offer the best development potential
• Develop a multiple-well production forecast that accounts for
differences in shale properties and potential interference between
wells
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7. Single Well Models
Flow Potential of Horizontal Laterals
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8. Single Well Models
Forecast Production for Drainage Area
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9. Single-Well Models
Test Different Well Types
Vertical Short Long
Well SIS SIS
110
Gas Rate Comparison for Different Well Types
Single-Well Analysis
Gas Rate Comparison
100
90 Vertical Well Horizonta Well (400') Horizontal Well (3000')
80
70
GAS (Mcfd )
60
50
40
30
20
10
0
01/06 01/07 01/08 01/09
01/09 01/10
01/10 01/11
01/11 01/12
01/12 01/13
01/13 01/14
01/14 01/15
01/15 01/16
01/16
DATE
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10. Multiple Well Model
Rank Development Potential
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11. Simulation – Model Stages
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12. Common Model Stages
The following apply to either single or multiple well models.
• Model Design
• Define the model objectives, boundaries and type
• Quality check the available measured data
• Identify how any missing input data will be estimated, such as
assuming the shale is similar to shale in another developed basin
• Parametric
• Identify the impact of changing individual input assumptions
• Determine what remaining data would be most valuable to collect
• Identify a reasonable range of outcomes
• Resource
• Calculate the original gas volume
• Reserve
• Estimate the volume of gas to be recovered or left to be recovered
• Integrate rate forecasts with capital and expense estimates to
calculate the financial return for different development scenarios
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13. Model Stages: Design
Model Boundaries
Lease Area and Resource Area
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14. Model Stages: Design
Define Level of Detail
Resource Model
55 Layers
430,500 cells
125m x 125m
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15. Model Stages: Parametric Study
SIM GAS CONTENT HORIZONTAL PERM TUFT Kz REL PERM COMPLETION WELL COUNT
ID Individually Test Influence of Fourteen Parameters
Vari. Undersat. Const. Undersat. 10 md 30 md 4 md 10%K 100%K 0.1%K Dry Wet BF 301 BF Coals 12 Wells 6 Wells
BF000 X X X X X X
BF001 X X X X X X
BF002 X X X X X X
BF003 X X X X X X
BF004 X X X X X X
BF005 X X X X X X
BF006 X X X X X X
BF007 X X X X X X
BF008 X X X X X X
VARYING TUFT Kz - DAILY GAS AND WATER RATES
1000
Gas and Water Rates
GAS RATE (ksm3/day); WATER RATE (sm3/day)
100
39
38
33
14
10
Gas and Water Rates
1
2005 2006 2007 2008 2009 2010
Base GAS Rate Base WATER Rate TuftKz = 10md TuftKz = 10md TuftKz = 0.01md TuftKz = 0.01md
Date
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16. Model Stages: Gas Resource
Volume Variability from Physical Changes
100
80
60
40
20
0
-20
-40
-60
-80
-100
-120
-140
-160
-180
-200
-220
-240
-260
-280
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17. Model Stages: Reserve Model
Account for Geologic Flow Features
Models to display and
evaluate known flow
barriers, baffles and
enhanced flow features.
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18. Model Stages: Reserves
Evaluate Different Well Patterns and Spacing
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19. Model Stages: Reserves
Financial Evaluation
Positive Operating Cash Flow Matrix
Completion Completion Completion
Type 1 Type 2 Type 3
Schedule A No No No
Schedule B Yes Yes No
Schedule C No Yes Yes
Gas Rate – (ksm3/day)
Water Rate sm3/day
• 0
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20. Simulation – History Matching
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21. Model Refinements: History Matching
• History matching is the process of changing the
model input properties to match the performance
of existing test or development wells
• Calibrating the model to actual production data
greatly improves the reliability of the model
• Procedures are available for defining how and
when key data should be collected as part of
initial production or pressure testing of a well
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