1. CO 2 Enhanced Oil Recovery Presented by (Team N): Lihui Ye Madison Tenneson Shatha Alnaji Wei Zhang PETE 4735 Spring, 2015 1

2. Outline Geological modeling Simulation Flood pattern Economics Rules and regulations Spring, 2015 PETE 4735 2

3. Data Collection Geologic Maps Salt Creek Field Tensleep area from UW Geology Department Little Buffalo Basin from WOGCC Wells Information Location (longitude and latitude) Production History Rock and fluid Properties Average porosity, permeability, oil gravity for several main formations Geological Modeling Spring, 2015 PETE 4735 3

4. Choose Target area Initial screening based on CO 2 scope Salt Creek Field has the best IRR, NPV and project life Compare different parts of Salt Creek Field Salt Creek Field was divided into several parts Compare the geological condition, production history and EOR potential Tensleep area in Northwest Salt Creek is the first choice Small basin located in Tensleep Little Buffalo Basin section 34 Geological Modeling Spring, 2015 PETE 4735 4

5. Little Buffalo Basin section 34 2 faults in this section One of the faults is too small, no effect on target formation This section contains 12 wells 2 injectors, 3 gas wells and 7 oil wells All the wells are vertical wells Target formation is Embar-Tensleep formation Total depth of the wells are all around 5000-6000 ft Datum of the geologic map is Phosphoria formation LayerFormation 1Dinwoody 2Phosphoria 3Embar 4Tensleep Geological Modeling Spring, 2015 PETE 4735 5

6. Spring, 2015 PETE 4735 Geological Modeling 6

7. Make Horizons Make horizons Adjust the contact relation Make layers Upscale Initial model has 1.42 million blocks Upscale to 30 in *30 in 33408 of grid blocks Export model Export to RESCUE file Available for CMG Import model into CMG Geological Modeling Spring, 2015 PETE 4735 7

8. Reservoir Simulation To provide essential input for CO 2 Scope software First production in 1944 Most wells drilled in 1970 WOGCC production history started in 1972 Spring, 2015 PETE 4735 8

9. Modeling Setup Horizontal permeability = 75 md Vertical permeability = 0 to separate each layer 3 layers for Embar-Tensleep formation Porosity = 16% 12 wells: each perforated at all layers of Embar- Tensleep Spring, 2015 PETE 4735 9

10. Cumulative Production Spring, 2015 PETE 4735 10

11. Production Rate Spring, 2015 PETE 4735 11

12. Water Cut At March 1995, the water cut surpassed 95%. We decided to start CO 2 injection at this point. Spring, 2015 PETE 4735 12

13. Injection pattern Direct line drive Staggered line drive Two, three, four, five, seven, and nine spot patterns. Normal Inverted 13 Spring, 2015 PETE 4735

14. Injection pattern Little Buffalo Basin issues Two reversed faults The CO 2 injection pattern Five spot pattern 14 Spring, 2015 PETE 4735

15. Economics 15

16. Mineral Lease Shares Federal Tribal State Private 100 % Federal Share Spring, 2015 PETE 4735 16

17. Royalties, Taxes, and EOR Credits Federal Lease Royalty Rate12.50 % Private Override5.25 % Tribal Royalty Rate18.75 % State Lease Royalty Rate16.67 % Private Lease Royalty Rate18.75 % Property Tax Rate6.77% State Severance Tax Rate6.00 % State Tribal Severance Tax Rate8.50 % Spring, 2015 PETE 4735 17

18. Wells Required and Related CAPEX Injection Well Equipping Costs = c 0 + c 1 D Where: c 0 = $95,000 (fixed) c 1 = $16 per foot D is well depth, in feet Production Well Equipping Costs = c 0 + c 1 D Where: c 0 = $23,000 (fixed) c 1 = $25 per foot D is well depth, in feet D = 5035ft Average Drilling Cost Spring, 2015 PETE 4735 18

19. Oil Pricing WYOGOV NYMEX ‐ WTI $49.96 Regional Discount ~ $13.25 Spring, 2015 PETE 4735 19

20. Electricity Infrastructure, Recycling Facility, Pipeline Electricity based on set Wyoming price Compression cost set higher as default 1 additional meter station 50 miles of pipeline from Big Horn Basin Area Spring, 2015 PETE 4735 20

21. NPV Spring, 2015 PETE 4735 21

22. Spring, 2015 PETE 4735 Laws and Regulations Carbon sequestration Wyoming Rules and Regulations: Long term CO 2 storage CO 2 transport and storage space Clarifying the purpose of CO 2 injection Federal rules and regulation 22

23. Spring, 2015 PETE 4735 Conclusion Geological modeling Simulation Flood pattern Economics Rules and regulation 23

24. Thank you for listening Questions? 24 Spring, 2015 PETE 4735

25. Geological Modeling Choose Target area Initial screening based on CO 2 scope Salt Creek Field has the best IRR, NPV and project life Compare different parts of Salt Creek Field Salt Creek Field was divided into several parts Compare the geological condition, production history and EOR potential Tensleep area in Northwest Salt Creek is the first choise Small basin located in Tensleep Little Buffalo Basin section 34 Spring, 2015 PETE 4735 25

26. Geological Modeling Little Buffalo Basin section 34 It is a small section located in Southwest of Tensleep Township is 48 N, Range is 100 W 2 faults in this section One of the faults is too small, no effect on target formation This section contains 12 wells 2 injectors, 3 gas wells and 7 oil wells Target formation is Embar-Tensleep formation Total depth of the wells are all around 5000-6000 ft Spring, 2015 PETE 4735 26

27. Digitization of Geologic map Calculate the longitude and latitude of four corners Set as the reference coordinates Convert longitude and latitude to geodetic coordinates To be more accurate and reduce error Converted by software Make polygons Contour lines Faults Formation Boundary Geological Modeling Spring, 2015 PETE 4735 27

28. Geological Modeling Data File Format Conversion Rearrange the data files in to proper format wellheader file and well tops file Imported the data files into software Wells and well tops can be viewed in 3D Match the location of the wells The error of wells and geologic map is very small Make manual adjustment Spring, 2015 PETE 4735 28

29. Generate formation surface Phosphoria generated first Since Phosphoria is the datum of the map Well tops and polygons of the faults are the limitation Fix the concave-convex points on the surface Upper and lower formation were generated Based on the surface of Phosphoria and well tops Totally 4 of the formations were created Geological Modeling LayerFormation 1Dinwoody 2Phosphoria 3Embar 4Tensleep Spring, 2015 PETE 4735 29

30. Define Fault Model Fault surface get converted to points Fault points get converted to fault model Created new 3D grid Grid size of 1 in 2 2D boundary polygons and fault model as limitation Pillar gridding Obtain the skeleton and the edges of the model Make Horizons Well tops as limitation Geological Modeling Spring, 2015 PETE 4735 30

31. Manually Adjusted The automatically generated contact relation between faults and four horizons were not as good as expected By adjusting the points of the fault Redo pillar gridding part and try several times Make layers 3 layers were made for each formation Easier to determine the perforation depth Geological Modeling Spring, 2015 PETE 4735 31

32. Upscale 1422000 of grid blocks for 1*1 grid size model Upscale to 30 in * 30in grid size 33408 of grid blocks after upscaling Export to RESCUE file RESCUE format is available for CMG Import the geological model into CMG Geological Modeling Spring, 2015 PETE 4735 32

33. Experimental Reservoir Depth8500 ft Initial Pressure4500 psi Porosity0.2 Avg horizontal permeability100 mD Vertical permeability0 Length1320 ft Width1320 ft Height50 ft Temperature200 F Oil weight35 API Oil saturation0.8 ¼ of a inverted 5 spot pattern Producer and Injector (1000 rb/day) both start on day 1 Simulation runs continuously for 25 years Maximum time step = 2 month, smallest time step determined automatically by simulator Implicit black oil simulator Works shown here will be applied to the actual reservoir model Spring, 2015 PETE 4735 33

34. Variation of horizontal permeability Used Dykstra-Parson coefficient to assign horizontal permeability to each layer Known average k = 100 mD Know standard deviation from D-P coefficient Used Excel create random numbers based on average and standard deviation, then adjusted by hand (excel does not have exact solution) LayerPermeability (mD) 1100 130956025 210011012112029155 3100801156017050 41008790809320 510010485166107200 6100951008271150 710010880110195180 8100 8010781120 9100101801108980 101001111207011020 Average Permeability 10099.6 100. 1 100 100. 5 100 Dykstra- Parson Coefficient 0.00 0 0.10 0 0.19 7 0.30 3 0.49 5 0.69 6 http://petrowiki.org/images/d/df/Vol5_page_1067_eq_001.png Spring, 2015 PETE 4735 34

35. Relative Permeability Swkrwkrow 0.200.8 0.231250.0011720.703125 0.26250.0046880.6125 0.293750.0105470.528125 0.3250.018750.45 0.356250.0292970.378125 0.38750.0421880.3125 0.418750.0574220.253125 0.450.0750.2 0.481250.0949220.153125 0.51250.1171880.1125 0.543750.1417970.078125 0.5750.168750.05 0.606250.1980470.028125 0.63750.2296870.0125 0.668750.2636720.003125 0.70.30 35

36. Discretization There is a very small difference (0.5%) in recovery factor at the end of 25 years that can be noticed after zooming in. Spring, 2015 PETE 4735 36

37. Effects of horizontal permeability Spring, 2015 PETE 4735 37

38. Effects of vertical permeability Spring, 2015 PETE 4735 38

39. Why not history matching? Certainly good to have, but time wise? Production history during initial years for most wells do not exist Perforation data not available, so perforated throughout the Embar-Tensleep formation Only a section of the basin, boundary condition not clear Spring, 2015 PETE 4735 39