Faults and Fractures in the Surat Basin: A Seismic Perspective

NW

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