SEISMIC WAVE PROPAGATION, ATTENUATION AND DISPERSIONIN FRACTURED POROUS RESERVOIRS

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SEISMIC WAVE PROPAGATION, ATTENUATION AND
DISPERSION IN FRACTURED POROUS RESERVOIRS
Boris GurevichCurtin University CSIRO
Petroleum Perth, Western Australia
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CSIROPetroleum Resources Exploration
Mining Curtin UniversityExploration
GeophysicsPetroleum Enginnering
CSIROPetroleum Resources Curtin
University University of Western Australia


Australian Resources Research CentreARRC
WA Energy Research AllianceWA ERA
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Fluid substitution in fractured reservoirs
Fluid
Dry rock Fluid fluid-saturated rock
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Low frequency results- Anisotropic Gassmann
equations

• Cikf (Kdry,mdry,f,ZN,ZT,Kfluid)
• Anisotropy parameters e, d, g (f, ZN, ZT, Kfluid)

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Low frequency e vs fluid modulus Kf
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Frequency dispersion due to fluid flow
h1
h2
h
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VELOCITY AND ATTENUATION vs FREQUENCY for
different porosities
Model - water-saturated sandstone with quartz as
a grain material (Kg37 GPa, µg44 GPa, ?g2.65
g/cm3) Fracture weakness is 20
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Numerical verification
Random Fractures Constant Fracture Thickness
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Model of penny-shaped cracks
Rathore et al. (1995)
Synthetic porous sandstone with aligned penny
shaped cracks Measured wave velocities as a
function of incident angle with ultrasonic source
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Saturated results - low frequency
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Saturated results frequency dependent
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Physical modelling
Construct model using layers of sand separated by
thin layers of water soluble plastic Use CIPS to
cement sand grains and create layers of porous
sandstone
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Well Log Data Example
Shear wave splitting
Fracture Azimuth from North
Gammaray Log
0.10
-60
Reservoir Interval
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Porous-fractured sand 3-D AVO modelling
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Method
Two conjugate fracture sets

• Monoclinic
• symmetry, use
• general S-K model

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Equilib.
Non-int.
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Patchy saturation (CSIROCurtin)
Measurements
Vp
Modelling
X-ray CT images
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Rock Physics Team

• Staff
• Prof. Boris Gurevich
• Dr. Tobias Müller
• Dr. Radim Ciz (CSIRO Postdoctoral Fellow)
• PhD Students
• Miroslav Brajanovski
• Gracjan Lambert
• Luke Brown
• Robert Galvin
• Interactions
• CRGC multicomponent project
• CSIRO Petroleum
• UWA, ANU, UNSW, FUB,