Source Rock Engineering Simulation Slides
- 1. Shale Gas Computer Simulation Models Prepared by Source Rock Engineering 26 May, 2010 www.sourcerockeng.com
- 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 .. 2
- 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 www.sourcerockeng.com 3
- 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 .. www.sourcerockeng.com 4
- 5. Simulation – Model Types .. www.sourcerockeng.com 5
- 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 www.sourcerockeng.com 6
- 7. Single Well Models Flow Potential of Horizontal Laterals www.sourcerockeng.com 7
- 8. Single Well Models Forecast Production for Drainage Area www.sourcerockeng.com 8
- 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 www.sourcerockeng.com 9
- 10. Multiple Well Model Rank Development Potential www.sourcerockeng.com 10
- 11. Simulation – Model Stages .. 11
- 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 12
- 13. Model Stages: Design Model Boundaries Lease Area and Resource Area www.sourcerockeng.com 13
- 14. Model Stages: Design Define Level of Detail Resource Model 55 Layers 430,500 cells 125m x 125m www.sourcerockeng.com 14
- 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 www.sourcerockeng.com 15
- 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 www.sourcerockeng.com 16
- 17. Model Stages: Reserve Model Account for Geologic Flow Features Models to display and evaluate known flow barriers, baffles and enhanced flow features. www.sourcerockeng.com 17
- 18. Model Stages: Reserves Evaluate Different Well Patterns and Spacing www.sourcerockeng.com 18
- 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 www.sourcerockeng.com
- 20. Simulation – History Matching .. 20
- 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 21