Flow Modelling Across Faults
Flow Modelling Across Faults SPE YP Technical Showcase Event 28 May 2013 Wahab Ahmed
Agenda
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
2
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
3
Fault Pattern
Parallel Fault or Bookshelf Model
Graben or Rift Fault
4
North Sea Examples
(After Glennie, 1990) Thistle Field (from Williams and Milne,1991)
5
Fault Zone
6
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
7
Fault Zone Properties
Fault Permeability
-Vshale vs Permeability relationship , Explicit ,SGR & Vclay methods (Manzocchi ,Sperrevik methods)
Fault Thickness - Estimation from Fault Displacement
8
Manzocchi Algorithm
D=Fault Displacement in m SGR=Shale Gouge Ratio K=Permeability in mD
9
Sperrevik Algorithm Fault rock clay content (Vf) Maximum rock burial depth and (Zmax) Depth at time of deformation (Zf)
10
Fault Thickness
Displacement to Thickness Ratio
Two Algorithms tf= D/66 (Hull, 1988) tf=D/170 (Walsh,1998)
11
Transmissibility Calculation
Transmissibility in X direction
12
Fault Transmissibility Multiplier
L1
L2 Trans12
K1 tf K2 KTrans1-f 1
Kf
Transf-2 Transfault
K2
L1
L2
Assumptions:
Intersection Area=1
No Grid block dips
1D single phase flow
13
Field Case Study-Gulfaks
5 Injectors in the west flank
5 Producers in the eastern flank
Injectors Control=Voidage replacement
14
Effect of Fault Permeability on Fault Transmissibility multiplier Fault Permeability=10mD
Fault Permeability=1mD
Fault Permeability=100mD
15
Effect of Fault Permeability on Flow Simulation
16
Fault Transmissibility multiplier (Manzocchi Vs Sperrevick Correlation) Sperrevik method for Fault Permeability from SGR
Manzocchi Method for Fault Permeability from SGR
17
Manzocchi Vs Sperrevick Correlation effect on Flow Simulation
18
Effect of Fault Thickness on Fault Transmissibility multiplier Thickness to Displacement Ratio=170 Walsh Correlation
Thickness to Displacement Ratio=66 Hull’s Correlation
Thickness to Displacement Ratio=100
19
Effect of Fault Thickness on Flow Simulation
20
Fault Threshold Pressure Pressure=2500 psi
Pressure=2550 psi
Fault Threshold Pressure=100 psi No Flow
Constant Fault Threshold Pressure - same value across the fault Variable Fault Threshold Pressure - different values for each cell connection across fault 21
Variable Fault Threshold Pressure
Vshale
Pressure (bar)
0
0
0.5
100
1
200
22
Transmissibility Multiplier for Fault Threshold Pressure Cases Fault Permeability=1 mD
Fault Permeability=10 mD
Fault Thickness to Displacement Ratio=66 23
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
Constant vs Variable Fault Threshold Pressure -10mD Case
25
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
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
27
Questions
Agenda
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
2
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
3
Fault Pattern
Parallel Fault or Bookshelf Model
Graben or Rift Fault
4
North Sea Examples
(After Glennie, 1990) Thistle Field (from Williams and Milne,1991)
5
Fault Zone
6
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
7
Fault Zone Properties
Fault Permeability
-Vshale vs Permeability relationship , Explicit ,SGR & Vclay methods (Manzocchi ,Sperrevik methods)
Fault Thickness - Estimation from Fault Displacement
8
Manzocchi Algorithm
D=Fault Displacement in m SGR=Shale Gouge Ratio K=Permeability in mD
9
Sperrevik Algorithm Fault rock clay content (Vf) Maximum rock burial depth and (Zmax) Depth at time of deformation (Zf)
10
Fault Thickness
Displacement to Thickness Ratio
Two Algorithms tf= D/66 (Hull, 1988) tf=D/170 (Walsh,1998)
11
Transmissibility Calculation
Transmissibility in X direction
12
Fault Transmissibility Multiplier
L1
L2 Trans12
K1 tf K2 KTrans1-f 1
Kf
Transf-2 Transfault
K2
L1
L2
Assumptions:
Intersection Area=1
No Grid block dips
1D single phase flow
13
Field Case Study-Gulfaks
5 Injectors in the west flank
5 Producers in the eastern flank
Injectors Control=Voidage replacement
14
Effect of Fault Permeability on Fault Transmissibility multiplier Fault Permeability=10mD
Fault Permeability=1mD
Fault Permeability=100mD
15
Effect of Fault Permeability on Flow Simulation
16
Fault Transmissibility multiplier (Manzocchi Vs Sperrevick Correlation) Sperrevik method for Fault Permeability from SGR
Manzocchi Method for Fault Permeability from SGR
17
Manzocchi Vs Sperrevick Correlation effect on Flow Simulation
18
Effect of Fault Thickness on Fault Transmissibility multiplier Thickness to Displacement Ratio=170 Walsh Correlation
Thickness to Displacement Ratio=66 Hull’s Correlation
Thickness to Displacement Ratio=100
19
Effect of Fault Thickness on Flow Simulation
20
Fault Threshold Pressure Pressure=2500 psi
Pressure=2550 psi
Fault Threshold Pressure=100 psi No Flow
Constant Fault Threshold Pressure - same value across the fault Variable Fault Threshold Pressure - different values for each cell connection across fault 21
Variable Fault Threshold Pressure
Vshale
Pressure (bar)
0
0
0.5
100
1
200
22
Transmissibility Multiplier for Fault Threshold Pressure Cases Fault Permeability=1 mD
Fault Permeability=10 mD
Fault Thickness to Displacement Ratio=66 23
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
Constant vs Variable Fault Threshold Pressure -10mD Case
25
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
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
27
Questions
