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CiPEG
Fault property Fault property modellingmodelling: recent : recent
advances and future directions advances and future directions
Quentin Fisher
Centre for Integrated Petroleum Engineering and Geoscience
School of Earth and Environment
University of Leeds
E-mail: [email protected]
www.see.leeds.ac.uk/cipeg
CiPEG
Fault transmissibility multipliersFault transmissibility multipliers
−++
−=
j
fj
f
f
i
fiij
k
tL
k
t
k
tLTrans
2
2
TM =
+
=
j
j
i
i
ij
k
L
k
LTrans
2
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Fault permeability databasesFault permeability databases
0.00001
0.0001
0.001
0.01
0.1
1
1 0
100
1000
10000
0 1 0 2 0 3 0 4 0 5 0 6 0 7 0
Clay content of host sediment (%)
Pe
rme
ab
ilit
y (
mD
)
Increasing burial depth
Rotliegend
Brent 2500 m
Brent 3500 m
>1000 measurements
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Mapping clay distributions along faultsMapping clay distributions along faults
Shale gouge ratio
used to estimate the
clay content of the
fault gouge along
each part of the fault
%100)(×
∆×=∑
t
zVSGR cl
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Is the fault rock property database helpful?Is the fault rock property database helpful?
Do the analysis of the properties of small faults
found in core really help predict the properties of
seismic-scale faults?
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Seismic analysis
StructuralLogging
Microstructuralanalysis
PetrophysicalProperty analysis
Flow Modelling
Fault plane map
Forward and inverse Forward and inverse modellingmodelling
Measurement Prediction Calibration
Dynamic data
Static data
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EvidenceEvidence--based practisebased practise
• New types of information are being constantly generated, which should, when we know and understand them, create frequent, major
changes in the advice that we give and the research that we conduct
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Simulation model using singleSimulation model using single--phase fault phase fault
permeabilitiespermeabilities
van der Molen et al., 2003)
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Gas relative permeability Gas relative permeability –– Hopeman Hopeman
faultfault
0.00
100.00
200.00
300.00
400.00
500.00
600.00
0.00 0.20 0.40 0.60 0.80 1.00
Water saturation
Cap
illa
ry p
ressu
re (
psi)
Al-Hinai et al, 2008
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History match achieved with twoHistory match achieved with two--
phase propertiesphase properties
Eclipse model
created in which a
local grid refinement
was used so we
could give fault its
own capillary
pressure and relative
permeability curves
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Transmissibilitymultiplier Water relative
permeability
Oil relative permeability0.0
1
0.5
BADLEY GEOSCIENCE LIMITED
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Stress dependence of relative Stress dependence of relative
permeabilitypermeability
Stress dependence of relative permeability during
loading
0.01
0.1
1
10
0 500 1000 1500 2000 2500
Effective stress (psi)
Krg
Sw = 44.4%
Sw = 40.5%
Sw = 66%
Dry Mam Tor samples
0
0.0005
0.001
0.0015
0.002
0.0025
0.003
0.0035
0 500 1000 1500 2000
Effective stress (psi)
Pe
rme
ab
ilit
y (
mD
)
K1
D1
A11
0
2
4
6
8
10
12
14
16
900 1100 1300 1500
Difference in effective stress (mD)
Perm
eab
ilit
y r
ati
o
Partially saturated
Dry
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Coupled fluid flow Coupled fluid flow -- geomechanicsgeomechanics
Synthetic seismic Coupled geomechanical
– production simulation
models
MP
I inte
rface
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Pore pressure
Effective Stress
MORE
ELFEN
Flow through Sealing faultCoupled fluid flow Coupled fluid flow -- geomechanicsgeomechanics
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B1 Pressure Main
4000
4200
4400
4600
4800
5000
5200
5400
5600
5800
6000
1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002
Time [year]
Pre
ss
ure
[p
si]
Alpha B1 Simulated
Bravo B1 Simulated
Charlie B1 Simulated
Alpha B1 Data
Bravo B1 Data
Charlie B1 Data
History match without fault propertiesHistory match without fault properties
From Jolley et al., Petroleum From Jolley et al., Petroleum GeoscienceGeoscience, 2007, 2007
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B1 Pressure Main
4000
4200
4400
4600
4800
5000
5200
5400
5600
5800
6000
1976 1978 1980 1982 1984 1986 1988 1990 1992 1994 1996 1998 2000 2002
Time [year]
Pre
ss
ure
[p
si]
Alpha B1 Simulated
Bravo B1 Simulated
Charlie B1 Simulated
Alpha B1 Data
Bravo B1 Data
Charlie B1 Data
History match with singleHistory match with single--phase fault phase fault
propertiesproperties
From Jolley et al., Petroleum From Jolley et al., Petroleum GeoscienceGeoscience, 2007, 2007
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Fault heterogeneityFault heterogeneity
Small windows with Small windows with
deformation products of deformation products of
clean sands will occur clean sands will occur
along most faults and along most faults and
control flow control flow –– particularly particularly
over geological timeover geological time--
scalesscales
Chances of barrier increases as permeability of
such windows decreases and threshold pressure
increases
BADLEY GEOSCIENCE LIMITED
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• Surprisingly similar, even though large faults are expected to
be more heterogeneous. Why?
• Childs et al (2007) have produced stochastic models of
disrupted shale smears (“PSSF”). With throws >> bed
thickness, the effective permeability of the fault zone is
equivalent to a simple log-linear relationship between SGR
and permeability.
Comparison of in-situ & lab calibrations
BADLEY GEOSCIENCE LIMITED
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SGR SGR –– different correlations for different different correlations for different
analyses?analyses?
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Discussion/ConclusionsDiscussion/Conclusions
• Signifcant advances being made on understanding fault rock properties
– Relative permeabilities
– Stress sensitivities
• Significant advances made in software for incorporating fault rock properties in simulation models (both relative
permeability and stress dependence)
– Far more work needed on calibrating databases (i.e.
putting properties into simulation models)
– Thorough fault seal analysis for production is still quite
rare
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Discussion/ConclusionsDiscussion/Conclusions
• Two-phase properties seem far more important when cataclastic fault rocks are present
– Are PFFRs really as important as previous studies have suggested?
– Probablistic clay smear method explains why SGR
often provides good results for production-fault seal analysis?
– What does this mean for fault rock seal over geological time?
• Multidisciplinary approach to fault seal appears to be making a step change in our understanding of
how faults affect flow in petroleum reservoirs
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Last wordsLast words
“I know that most men (sic), including those at ease with problems of the greatest complexity, can seldom accept even the simplest and most obvious truth if it
be such as would oblige them to admit the falsity of conclusions which they have delighted in explaining
to colleagues, which they have woven, thread by thread, into the fabric of their lives.” Leo Tolstoy