Ms Jane Cunneen

Degree: PhD

Telephone: +61 (08) 6488 7847
Fax: +61 (08) 6488 7848
E-Mail:jcunneen@tsrc.uwa.edu.au

Research Affiliations

• Tectonics Special Research Centre

Fig1 - Seismic line from the Laminaria area, showing Pliocene
and Pleistocene synsedimentary growth against faults.

Keywords

• Neogene, Timor Sea, reactivation, fault population analysis, strain.

Supervisor

• Dr Myra Keep (UWA)

Project Funding

• SPIRT grant involving UWA, Woodside Energy Ltd. and Shell Development Australia

Scholarships

• Australian Postgraduate Award (Industry); Faculty of Science top-up scholarship.

Project Description

• ” Neogene deformation styles and fault reactivation in the Timor Sea, Northwest Australia. “ This project is part of a SPIRT project at UWA, sponsored by Woodside Energy Ltd. and Shell Development Australia. 
   

Tertiary collision between Australia and the Banda Arc resulted in pervasive deformation of Australia’s North West Shelf and accretion of the Timor Prism to its leading edge.  The oblique nature of the collision has resulted in a range of structural styles in the Timor Sea region, some of which affect hydrocarbon trap integrity.  The aims of this study are to produce a complete Neogene structural and tectonic history of the Timor Sea region, including time and depth structure maps of Neogene horizons and detailed study of Neogene fault populations, to be used as a predictive tool for exploration. 

All seismic and well data was supplied by Woodside Energy Ltd.  Mapping was conducted using Landmark Graphics’ Openworks, Seisworks and Stratworks software on Unix workstations. Well data for over 500 wells was examined, and horizon picks were made using 110 wells with logs for the Tertiary section.  A 2D seismic grid was acquired with over 4000 open-file seismic lines, and tied using the well picks.  Five Tertiary horizons and two Mesozoic horizons were interpreted across the entire area, and faults were interpreted and correlated across lines where possible.  Spatial analysis of the resulting fault maps used Arc Info and ERMapper software.

A 3D seismic dataset over the Laminaria area in the Timor Sea allowed more detailed examination of Tertiary faulting and sedimentation.  Ten Tertiary horizons were interpreted across the dataset and tied with picks from up to seven wells.  The Neogene fault population was analysed using both interpreted faults and mapped fault segments from semblence data.  Analysis of fault parameters such as length, displacement, dip direction, orientation and spacing was used to constrain a model for Neogene fault evolution and growth and predict the likelihood of trap breach in the area. 

The final tectonic model reconciles the apparent contradiction of pervasive extensional normal faulting across a region involved in oblique plate collision.  The initial stages of collision in the Miocene resulted in flexural amplification of the basement topography and widespread shallow normal faulting in the sedimentary cover.  The continuing collision and emplacement of the Timor prism onto the leading edge of the northern Australian margin resulted in deformation becoming increasingly localised to the Timor Trough region throughout the Pliocene and Pleistocene.  This changing deformation regime has important implications for trap breach, especially where migration and charge has occurred in the past 3Ma.  

Click here for a list of publications.