Faults and Fractures in the Surat Basin: A Seismic Perspective - … · a School of Earth Sciences,...
Transcript of Faults and Fractures in the Surat Basin: A Seismic Perspective - … · a School of Earth Sciences,...
Faults and Fractures in the Surat Basin: A Seismic Perspective
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PRELIMINARY RESULTS
NW SENW SE
Bowen Deformation:• Bowen age deformation underpins and partially controls major Surat age deformation• Major structures are primarily vertical and bounded by high angle reverse faults• Fault morphology for larger structures is complex due to apparent shear componentSurat Deformation (Cenozoic):• Pre-Surat complex structures are reactivated as folds with small faults in Cenozoic def.• Faults rarely are re-activated directly to continue along same plane• Keystone structures prevalent where remnant Permian coals subcrop• Transpressive shear results in distinctive “keystone” deformation in Walloon
T. Permian J20.0 - “EverLow” (Westgrove Ironstone) J50.2 – “Lower Springbok”
C.I. – 20 ms C.I. – 10 ms C.I. – 10 ms
- “Keystone Block”- Base Surat Fault
Undulla NoseKogan Nose
Wambo
INTRODUCTION
The faults and fractures project has a focus on understanding the mechanisms behind the large variation in permeability in the Walloon Coal Measures. The contribution of underlying structure and the succession of deformation to fracture development is not well understood. This portion of the project was intended to better understand the deformation affecting the Surat succession and the dependence on pre-existing structural fabric. Primary Walloon faulting is related to transpressional style deformation. Permian subcrop is associated with an increased density of faulting.
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ACKNOWLEDGEMENT
Jeff Copley ab , Saswata Mukherjee ab & Joan Esterleab
a School of Earth Sciences, The University of Queensland, b Centre of Coal seam Gas, The University of Queensland Project: Understanding Faults and Fractures in the Surat Basin
The authors would like to thank UQ’s Centrefor Coal Seam Gas and its industry members(APLNG, Arrow Energy, QGC and Santos) forproviding research funding and support. Aspecial thank you to Schlumberger forproviding the software packages and support.
Uplifted block
Uplifted blocks
Moonie complex
~650 ms
~1100m
400 800 1200(TWT ms)
1600
500
1000
1500
2000
2500
Dep
th (
m)
~500m
~650ms
(data collection credit – Andrew Aouad, Origin)
Talinga 1 TDRDatum shift
13 Wells(@244m)
Base Permian
Base Permian
Extensional w complex shear
~20m
J52.0
J50.2
J20 - Westgrove
J10.0 – Base Surat
Permian
Permian
Permian
Ductile Folding
Net Bsmt Uplift~700ms/~1.2km
Transferred Shear
Coal
Permian
Coal
Ductile Folding
Net Bsmt Uplift~600ms/~1km
Gentle Folding
minor faulting
Moonie Structure
Broad fold, no faulting
Permian
Gentle Folding
minor faulting
Transferred Shear
Condamine
Walloon
Base Surat
Permian
Dalwogan-Condabri 3D(Origin)
Coherency time slice
A
B
A B
Walloon
Permian
Checkshot Summary
Complex Fault
Morphology
T. Permian
Base Surat
J20.0 - Westgrove
J50.2 ~ Intra-Springbok
~5200m
Extensional Keystone
above basin bounding uplift
over 20 km strike
5-10 m displacement
Complex Bowen Fault Morphology
Dalwogan-Condabri 3DCoherency Volume Time-Slice
Net Bsmt Uplift~200ms/~300m
Fold Width~5000m
Erosion at Faultzone
SE
Transfer
- “Keystone Block”- Base Surat Fault- L. Permian Subcrop
25 km25 km25 km
~4000m
Base Walloon
~5-10m