1 / 34

Overburden Pressure Affects Fracture Aperture and Permeability in a Stress-Sensitive Reservoir

Overburden Pressure Affects Fracture Aperture and Permeability in a Stress-Sensitive Reservoir. Vivek Muralidharan. Fracture. Permeability. Matrix. Permeability. Porosity. Problems. Fracture behavior is complex. Overburden Pressure affects fracture parameters. What has been done.

columbia-adriel
Télécharger la présentation

Overburden Pressure Affects Fracture Aperture and Permeability in a Stress-Sensitive Reservoir

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Overburden Pressure Affects Fracture Aperture and Permeability in a Stress-Sensitive Reservoir Vivek Muralidharan

  2. Fracture Permeability Matrix Permeability Porosity

  3. Problems • Fracture behavior is complex. • Overburden Pressure affects fracture parameters.

  4. What has been done • Observed the change in permeability with overburden pressure(Fatt and Davis, 1952; Jones,1975 and Cook et al, 2001). • Measured fracture aperture physically (Jones et al, 1968; Gentier,1986; Arun et al,1997). • Studied the effect of overburden pressure using unfractured cores(Holt,1990; Keaney et al,1998).

  5. What has not been done • Determination of fracture aperture during fluid flow. • Determination of matrix and fracture flow contributions.

  6. Approach • Perform laboratory experiments with different overburden pressure. • Develop an equation to determine the fracture aperture and flow contributions. • Perform simulation modeling based on experimental results.

  7. Approach • Perform laboratory experiments with different overburden pressure. • Develop an equation to determine the fracture aperture and flow contributions. • Perform simulation modeling based on experimental results.

  8. Laboratory Experiments • How do we analyze the experimental results ? • What information can be deduced from experimental results? • Fracture Aperture • Fracture permeability • Matrix and fracture flow contributions • How these properties change with overburden stress

  9. Experimental Apparatus

  10. Permeability changes at variable overburden pressure kav km

  11. Approach • Perform laboratory experiments with different overburden pressure. • Develop an equation to determine the fracture aperture and flow contributions. • Perform simulation modeling based on experimental results.

  12. w l A L Experimental Data Analysis Fracture Permeability : Parallel plate assumption: Combining above equations to determine w: Contribution of flow from matrix and fracture systems:

  13. 0.006 0.006 5 cc/min 5 cc/min 5 cc/min 5 cc/min 5 cc/min 0.005 0.005 0.004 0.004 500 psia 1000 psia 1500 psia 20 cc/min 20 cc/min 20 cc/min 20 cc/min 20 cc/min 0.003 0.003 Fracture Aperture (cm) w w w w w w w w w w w w w w w 0.002 0.002 0.001 0.001 0 0 0 0 200 200 400 400 600 600 800 800 1000 1000 1200 1200 1400 1400 1600 1600 Overburden Pressure ( Psia ) ) ) 5 cc/min 5 cc/min 5 cc/min 10 cc/min 10 cc/min 10 cc/min 15 cc/min 15 cc/min 15 cc/min 20 cc/min 20 cc/min 20 cc/min 5 cc/min 5 cc/min 10 cc/min 10 cc/min 15 cc/min 15 cc/min 20 cc/min 20 cc/min Fracture Aperture

  14. Fracture Permeability OR

  15. W1 W2 W2 < W1 Fracture Permeability OR

  16. 16.00 16.00 16.00 14.00 14.00 14.00 20 cc/min 12.00 12.00 12.00 5 cc/min 5 cc/min 10.00 10.00 10.00 Fracture Flow Rate (cc/min) K = = 200 = md md md 8.00 8.00 8.00 K = = 200 md md m m m m m K K = 10,000 = = = 10,000 = - - - - - 50,000 50,000 md md md md md f f f f f 6.00 6.00 6.00 4.00 4.00 4.00 2.00 2.00 2.00 0.00 0.00 0.00 0 0 0 200 200 200 400 400 400 600 600 600 800 800 800 1000 1000 1000 1200 1200 1200 1400 1400 1400 1600 1600 1600 Overburden Pressure ( Psia ) 5 cc/min 5 cc/min 10 cc/min 10 cc/min 15 cc/min 15 cc/min 20 cc/min 20 cc/min Fracture Flow Rate

  17. 16.00 16.00 16.00 14.00 14.00 14.00 20 cc/min 12.00 12.00 12.00 5 cc/min 5 cc/min 10.00 10.00 10.00 Fracture Flow Rate (cc/min) K = = 200 = md md md 8.00 8.00 8.00 K = = 200 md md m m m m m K K = 10,000 = = = 10,000 = - - - - - 50,000 50,000 md md md md md f f f f f 6.00 6.00 6.00 4.00 4.00 4.00 2.00 2.00 2.00 0.00 0.00 0.00 0 0 0 200 200 200 400 400 400 600 600 600 800 800 800 1000 1000 1000 1200 1200 1200 1400 1400 1400 1600 1600 1600 Overburden Pressure ( Psia ) 5 cc/min 5 cc/min 10 cc/min 10 cc/min 15 cc/min 15 cc/min 20 cc/min 20 cc/min Fracture Flow Rate

  18. 25.00 20.00 20 cc/min 15.00 5 cc/min Matrix Flow Rate (cc/min) 10.00 5.00 0.00 0 0 200 400 600 800 1000 1200 1400 1600 Overburden Pressure ( Psia ) ) 5 cc/min 5 cc/min 5 cc/min 10 cc/min 10 cc/min 10 cc/min 15 cc/min 15 cc/min 15 cc/min 20 cc/min 20 cc/min 20 cc/min 5 cc/min 5 cc/min 10 cc/min 10 cc/min 15 cc/min 15 cc/min 20 cc/min 20 cc/min Matrix Flow Rate

  19. Approach • Perform laboratory experiments with different overburden pressure. • Develop an equation to determine the fracture aperture and flow contributions. • Perform simulation modeling based on experimental results.

  20. Modeling Laboratory Experiment • Is single fracture aperture sufficient for modeling the flow through the fracture? • Model for future reservoirs

  21. Simulation Parameters • Single phase black oil simulation • Laboratory dimensions (4.9875” x 2.51”) • 31x1x31 layers • Matrix porosity = 16.764% • Matrix permeability = 296 md • Fracture properties is introduced in 16th layer • Fracture porosity = 0.56% • Mean fracture aperture = 56.4 micro meter

  22. Example of flow through single fracture aperture

  23. Inlet Pressure Injection Rate Fracture Flow Matrix Flow Outlet Pressure Simulation Result for 500 psi and 5cc/min Flow

  24. Observed Simulated Fracture Matrix Match between Laboratory data and Simulation Results for 500 psi and 5cc/min flow

  25. Observed Simulated Match between Laboratory data and Simulation Results for 5 cc/min

  26. ActualFractureFace

  27. Lesson Learned ! • Single fracture aperture cannot be used in modeling the experimental data. • The fracture aperture must be distributed.

  28. Log-normal Distribution of Fracture Aperture

  29. Variogram Modeling to Generate Fracture Aperture Distribution

  30. Core Surface Generated after Krigging

  31. Example of flow through different fracture spatial heterogenity

  32. Conclusions • Effect of stresses are most pronounced in fractured reservoirs. • The fracture aperture equation has been developed and thus, the matrix and fracture flow contributions can be estimated. • The spatial heterogeneity in the fracture aperture must be included in the modeling of fracture system.

  33. Acknowledgement • Dr. D. S. Schechter, Texas A&M University • Dr. Erwin Putra, Texas A&M University • Department of Energy (D.O.E) for sponsoring the project.

More Related