1. Vivek Muralidharan Simulation and imaging experiments of fluid flow through a fracture surface: a new perspective

2. Log Analysis Fracture Characterization Aperture distribution Fracture Model Fractured Reservoirs Poor recovery Laboratory Experiments Simulation X-ray CT scanner

3. Presentation Outline Historical PerspectiveHistorical Perspective Objectives and ApproachObjectives and Approach ApplicationsApplications Conclusions

4. Fracture Model Historical perspective w Constant fracture aperture

5. Historical perspective Cubic Law Aperture Size

6. Parallel Plate Assumption w Single Fracture Aperture

7. Fracture Aperture Fracture roughness Better History Match Realistic simulation model

8. Fracture Aperture Distribution Fracture aperture distribution Pyrak-Nolte et al., (1987) Tsang et al., 1987 Gale, 1987 Keller, (1996) Lognormal distribution for natural fractures

9. Log-Normal Mean Log-Normal Deviation Variable ( Aperture ) Apertures distributed log-normally Lognormal Function

10. Generation of apertures

11. Smooth fracture surface Aperture Distribution

12. Slightly rough fracture surface

13. Highly rough surface fracture Aperture Distribution Larger Aperture Size

14. Problems Aperture distribution is proved for fractures without experiencing any stress. Aperture distribution has not yet been investigated under different stress condition. Single fracture aperture does not represent the actual flow through fracture

15. Presentation Outline Historical PerspectiveHistorical Perspective Objectives and ApproachObjectives and Approach ApplicationsApplications Conclusions

16. Objectives X-ray CT scanner Stress Aperture distribution? Aperture distribution has not yet been investigated under different stress condition. Problem:

17. Objectives X-ray CT scanner Gravity drainage experiment Single fracture aperture does not represent the actual flow through fracture Problem:

18. Aperture distribution under stress using X-ray CT scanner

19. Experiments in X- ray CT scannerApproach Scan Scans at multiple locations Calibration Aperture Distribution

20. X-ray CT Scanner CT scanner analyzes density differences between objects Matrix and fracture identification Density of rock Density of fluid in fracture

21. 1000 1200 1400 1600 020406080 Pixel number CT number X-ray CT Scans Matrix Fracture CT numbers are different from actual aperture size Calibration Technique to correlate CT to obtain fracture aperture size No direct measurement of fracture aperture

22. Scanned the core between feeler gauges Calibration Procedure Smooth surface Feeler gauge of known size

23. Calibration Procedure Fracture Matrix

24. Min rock CT Calibration Procedure Integrated CT area

25. Calibration Curve Feeler gauge size

26. Calibration curve Integrated CT area Scans of fractured core of unknown apertures Fracture aperture

27. Calibration Curve Determination of fracture aperture

28. Aperture Distribution

29. Scans taken along the length of the core

30. Animation Apertures along the length of the core No stress 500 psi 1000 psi 1500 psi

31. Apertures 90 sections 70 locations Around 6000 sections Four different stress conditions 24000 apertures Apertures are calculated from calibration curve

32. Aperture Distribution without stress Lognormal distribution Mean = 370.527 σ = 211.772

33. Aperture Distribution with stress Mean = 370.527, σ = 211.772 Mean = 197.997, σ = 172.573

34. Aperture Distribution with stress Mean = 370.527, σ = 211.772 Mean = 197.997, σ = 172.573 Mean = 157.418, σ = 162.395

35. Aperture Distribution with stress Mean = 370.527, σ = 211.772 Mean = 197.997, σ = 172.573 Mean = 157.418, σ = 162.395 Mean = 138.656, σ = 150.33

36. Aperture Distribution with stress Aperture distribution follows Lognormal distribution at all conditions

37. Highly rough surface fracture Larger Aperture Size Fracture apertures have to be distributed Lognormal Distribution

38. Presentation Outline Historical PerspectiveHistorical Perspective Objectives and ApproachObjectives and Approach ApplicationsApplications Conclusions

39. Experimental Procedure Unfractured Core pp Pressure Drop K m  q inj /  p Matrix Permeability q inj Injection rate 5 cc/min 500,1000, 1500

40. matrix fracture l Experimental Procedure Fractured Core  p avg Average Pressure Drop K avg  q inj /  p avg Average Permeability q inj Injection rate 5 cc/min

41. Analytical Equations

42. Fracture Permeability Area of fracture Matrix Permeability Area of matrix Average Permeability Total area of core

43. Analytical Equations Combining above equations to determine w w A d matrix fracture Fracture Permeability Cubic Law

44. Fracture Aperture

45. Fracture Permeability

46. Fracture Flowrate 500 Psi 1000 Psi 1500 Psi

47. Flow through fracture and matrix Flow through fracture

48. Flow through fracture and matrix Flow through fracture Flow through matrix

49. Modeling Laboratory Experiment Simulation model using aperture distribution

50. Simulation Model Model Description 10x10x15 grids Fracture in 8 th block in K dirn i j k

51. Injector Water Injection Producer - matrix Matrix Production rate Producer - fracture Fracture Production rate Water prod

52. Aperture distribution in fracture region Aperture distribution maps Lognormal Mean eff aperture variance 500 psi 1000 psi 1500 psi

53. Example flow on the distributed fracture surface

54. Flow Through Matrix and Fracture Flow through fracture Flow through matrix

55. Pressure drop

56. Objectives X-ray CT scanner Gravity drainage experiment

57. Approach Gravity Drainage Experiment

58. X-Ray Detector X-Ray Source Brine X-ray CT scan

59. Fluid flow pattern 0 min 12 min

60. Parallel Plate Experiment Simulation

61. Flow on a smooth fracture surface

62. Lognormal distribution Fluid flow using aperture distribution

64. Saturation Experiment Simulation

65. Presentation Outline Historical PerspectiveHistorical Perspective Objectives and ApproachObjectives and Approach ApplicationApplication Conclusions

66. Fluid flow experiments under stress Recap

67. Gravity drainage experiment

68. Conclusions Fracture Aperture Lognormal distribution Parallel plate assumption valid Distributed apertures Realistic flow behavior Better History Match

69. Acknowledgement Dr. D. S. Schechter, Texas A&M University Dr. Erwin Putra, Texas A&M University Mr. Dicman Alfred, Schlumberger Department of Energy (D.O.E) for sponsoring the project.

70. Thank You