SLIDE 1
Flow Modelling Across Faults
SPE YP Technical Showcase Event
28 May 2013 Wahab Ahmed
SLIDE 2 Faults-Introduction Fault Pattern Fault Zone Properties
– Fault Permeability, Fault Thickness
Fault Transmissibility Multiplier Calculation Fault Threshold Pressure
– Constant Fault Threshold Pressure , Variable Fault Threshold Pressure
Wrap-up
– Conclusions , References
Agenda
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SLIDE 3 Fault
Fault
Fault is a fracture, fissure or joint along which there have been relative displacement
Normal Faults
Normal fault is one in which the hanging wall falls down relative to the foot wall due to tensional stress
Reverse Faults
Reverse fault is one in which the hanging wall moves up relative to the foot wall due to compression
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SLIDE 4 Fault Pattern
Parallel Fault or Bookshelf Model Graben or Rift Fault
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SLIDE 5
North Sea Examples
(After Glennie, 1990) Thistle Field (from Williams and Milne,1991)
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SLIDE 6
Fault Zone
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SLIDE 7 Factors affecting Fault zone seal
Fault zone architecture
Burial and Fault History and Juxtaposition of lithologies
Local facies
Pressure difference across fault
Reservoir fluid type and saturation
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SLIDE 8 Fault Zone Properties
Fault Permeability
- Vshale vs Permeability relationship , Explicit ,SGR &
Vclay methods (Manzocchi ,Sperrevik methods)
Fault Thickness
- Estimation from Fault Displacement
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SLIDE 9
Manzocchi Algorithm
D=Fault Displacement in m SGR=Shale Gouge Ratio K=Permeability in mD
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SLIDE 10
Sperrevik Algorithm
Fault rock clay content (Vf) Maximum rock burial depth and (Zmax) Depth at time of deformation (Zf)
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SLIDE 11
Fault Thickness
Displacement to Thickness Ratio
Two Algorithms tf= D/66 (Hull, 1988) tf=D/170 (Walsh,1998)
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SLIDE 12
Transmissibility Calculation
Transmissibility in X direction
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SLIDE 13 Fault Transmissibility Multiplier
K1 K2 K2 K1 Kf L1 L2 L2 L1 tf
Trans12 Trans1-f Transf-2 Transfault
Assumptions:
Intersection Area=1
No Grid block dips
1D single phase flow
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SLIDE 14 Field Case Study-Gulfaks
5 Injectors in the west flank 5 Producers in the eastern flank Injectors Control=Voidage replacement
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SLIDE 15
Effect of Fault Permeability on Fault Transmissibility multiplier
Fault Permeability=1mD Fault Permeability=10mD Fault Permeability=100mD 15
SLIDE 16
Effect of Fault Permeability on Flow Simulation
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SLIDE 17
Fault Transmissibility multiplier (Manzocchi Vs Sperrevick Correlation)
Manzocchi Method for Fault Permeability from SGR Sperrevik method for Fault Permeability from SGR 17
SLIDE 18 Manzocchi Vs Sperrevick Correlation effect
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SLIDE 19
Effect of Fault Thickness on Fault Transmissibility multiplier
Thickness to Displacement Ratio=100 Thickness to Displacement Ratio=66 Hull’s Correlation Thickness to Displacement Ratio=170 Walsh Correlation 19
SLIDE 20
Effect of Fault Thickness on Flow Simulation
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SLIDE 21 Fault Threshold Pressure
Constant Fault Threshold Pressure
- same value across the fault
Variable Fault Threshold Pressure
- different values for each cell connection across fault
Pressure=2500 psi Pressure=2550 psi
Fault Threshold Pressure=100 psi No Flow 21
SLIDE 22 Variable Fault Threshold Pressure
Vshale Pressure (bar) 0.5 100 1 200
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SLIDE 23
Transmissibility Multiplier for Fault Threshold Pressure Cases
Fault Permeability=1 mD Fault Permeability=10 mD Fault Thickness to Displacement Ratio=66 23
SLIDE 24 Constant vs Variable Fault Threshold Pressure -1mD Case
Early breakthrough for Variable Fault Threshold Pressure Case & gentle increase in water cut
Difference in water cut is significant for lower values of Fault Permeability 24
SLIDE 25
Constant vs Variable Fault Threshold Pressure -10mD Case
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SLIDE 26 Conclusion
Fault zone Thickness and Permeability are important for
flow modelling
Fault Permeability affects are more significant between 1mD
and 10 mD
– Manzocchi algorithm gives low values of Fault Transmissibility multiplier as compare to Sperrevik
Fault Displacement is used to predict fault thickness
– Fault Transmissibility will be higher for higher value of Fault Displacement to Thickness ratio
Fault Threshold pressure prevents the flow across fault interface
– Early water breakthrough and gentle increase will be observed for variable fault threshold pressure case as compare to constant fault threshold pressure 26
SLIDE 27 References
- 1. Manzocchi, T. et al. (1999). “Fault transmissibility multipliers for flow simulation models”, Petroleum Geoscience, Vol. 5,
- pp. 53-63
- 2. Sperrevik, S. et al. (2002). “Empirical estimation of fault rock properties”, In: Hydrocarbon Seal Quantification (edited
by Koestler, A.G and Hunsdale, R), NPF Special Publication 11, pp 109 -125.
- 3. Fisher, Q.J. et al. (Jan. 2006). ”Microstructural and Petrophysical Properties of Fault Rocks from the Snorre Field”,
Rock Deformation Research Group, report 9454
- 4. Jonas Cordazzo , Clovis Raimundo Maliska , Antonio Fabio Carvalho da Silva Interblock Transmissibility Calculation
Analysis for Petroleum Reservoir Simulation Department of Mechanical Engineering, Federal University of Santa Catarina . Brazil , pp 5 -7
- 5. Reservoir Structure Course material of IPE Heriot Watt University by Dr J Couple
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SLIDE 28
Questions
