28_MAY_2013 Wahab Ahmed - FlowModellingAcrossFault
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Transcript of 28_MAY_2013 Wahab Ahmed - FlowModellingAcrossFault
Flow Modelling Across Faults
SPE YP Technical Showcase Event 28 May 2013
Wahab Ahmed
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
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
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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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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)
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Transmissibility Calculation
Transmissibility in X direction
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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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Field Case Study-Gulfaks
5 Injectors in the west flank
5 Producers in the eastern flank
Injectors Control=Voidage replacement
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Effect of Fault Permeability on Fault
Transmissibility multiplier
Fault Permeability=1mD Fault Permeability=10mD
Fault Permeability=100mD
15
Effect of Fault Permeability on Flow
Simulation
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Fault Transmissibility multiplier (Manzocchi
Vs Sperrevick Correlation)
Manzocchi Method for Fault
Permeability from SGR
Sperrevik method for Fault
Permeability from SGR
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Manzocchi Vs Sperrevick Correlation effect
on Flow Simulation
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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
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Effect of Fault Thickness on Flow Simulation
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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
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Variable Fault Threshold Pressure
Vshale Pressure
(bar)
0 0
0.5 100
1 200
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Transmissibility Multiplier for Fault Threshold
Pressure Cases
Fault Permeability=1 mD Fault Permeability=10 mD
Fault Thickness to Displacement Ratio=66
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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
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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
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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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Questions