1. Group PresentationOctober 2002 Fluid Flow Through The Fracture under Different Stress-state Condition Vivek Muralidharan Dicman Alfred Dr. Erwin Putra Dr. David Schechter

2. Group PresentationOctober 2002 CORE HOLDER PERMEAMETER HYDRAULIC JACK Matrix 4.98 Cm A=4.96 Cm 2 Fracture Graduated Cylinder Accumulator 1Accumulator 2 PUMP 1 Graduated Cylinder BLACK RED Schematic of Experiment Apparatus

3. Group PresentationOctober 2002 Overburden experiments for unfractured core Overburden experiments for fractured core Experimental Results

4. Group PresentationOctober 2002 Permeability changes at variable overburden pressure kmkm k av

5. Group PresentationOctober 2002 Motivation How do we analyze the experimental results ? What information can be deduced from experimental results? Fracture permeability Fracture Aperture Matrix and fracture flow contributions How these properties change with overburden stress How do we model this experiment ?

6. Group PresentationOctober 2002 Experimental Data Analysis w A l Parallel plate assumption: Average Permeability : Combine above equations to determine w: Contribution flow from matrix and fracture systems:

7. Group PresentationOctober 2002 or Fracture Permeability      : Hysteresis

8. Group PresentationOctober 2002 Fracture Aperture 500 psia1000 psia1500 psia w w w

9. Group PresentationOctober 2002 Matrix Flow Rate Dual PorosityDual PermeabilitySingle Porosity

10. Group PresentationOctober 2002 Fracture Flow Rate K m = 200 md K f = 10,000-50,000 md Dual PorosityDual PermeabilitySingle Porosity

11. Group PresentationOctober 2002 Modeling Laboratory Experiment

12. Group PresentationOctober 2002 Simulation Parameters  Single phase black oil simulation  Laboratory dimensions (4.9875” x 2.51”)  31x1x31 layers  Matrix porosity = 0.16764  Matrix permeability = 296 md  Fracture properties is introduced in 16 th layer  Fracture porosity = 0.00563972  Mean fracture aperture = 56.4 micro meter  Fracture aperture is varied using log normal distribution and geostatistical approach  Fracture permeability is generated from fracture aperture distribution using modified parallel plate model

13. Group PresentationOctober 2002 Example of flow through single fracture aperture

14. Group PresentationOctober 2002 Simulation Results

15. Group PresentationOctober 2002 Match between Laboratory data and Simulation Results

16. Group PresentationOctober 2002 Match between Laboratory data and Simulation Results (Continued)

17. Group PresentationOctober 2002 The fracture aperture (fracture permeability) must be distributed Lesson Learned !

18. Group PresentationOctober 2002 Actual Fracture Face

19. Group PresentationOctober 2002 Log-normal Distribution of Fracture Aperture

20. Group PresentationOctober 2002 Generated Core Surface from Log Normal Distribution

21. Group PresentationOctober 2002 Variogram Modeling to Generate Fracture Aperture Distribution

22. Group PresentationOctober 2002 Core Surface Generated after Krigging

23. Group PresentationOctober 2002 Example of flow through different fracture apertures

24. Group PresentationOctober 2002 1.Change in overburden pressure significantly affects the reservoir properties. 2.The change in matrix permeability under variable overburden pressures is not significant in contrast with that effect on fracture aperture and fracture permeability. 3.The simulation results suggest that a parallel model is insufficient to predict fluid flow in the fracture system. Consequently, the spatial heterogeneity in the fracture aperture must be included in the modeling of fluid flow through fracture system. Conclusions

25. Group PresentationOctober 2002 5.The results also infer that the effect of stresses may be most pronounced in fractured reservoirs where large pressure changes can cause significant changes in fracture aperture and related changes in fractured permeability. 6.At high overburden pressure the influence of existing fracture permeability on fluid flow contributor in permeable rocks (> 200 md) is not too significant. Conclusions (Cont’d)