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Integrating Geology and Geophysics to Uncover Permian Stratigraphic Traps in the Caladan/Daralingie Region

Sally Gregerson

Honours - Bachelor of Science (Petroleum Geology & Geophysics)- 2014

Australian School of Petroleum

The University of Adelaide


Abstract

The purpose of this study was to determine whether the Early Permian Patchawarra Formation sedimentary fill was dominated by either glacial geomorphology or by faulting in the Caladan/Daralingie area, Cooper Basin. Variable success finding reservoir quality sandstone on structural highs has led to a re-evaluation of pre-existing basement interpretations and reactivated Early Permian growth structures. This analysis was able to give a better understanding of how these structural controls can influence the thickness of the Patchawarra Formation. This was done by interpreting three dimensional (3D) seismic data over Waukatanna, Bobs Well, and Yalcumma gas fields on the Daralingie Shelf, west of the Wooloo Trough. This was achieved by: [1] developing a classification scheme in order to differentiate between glacial features and faulting observed within the 3D seismic survey; [2] creating a structure map of the base-Permian, Cooper Basin; [3] generating an isochron of the base-Permian to top Patchawarra to understand the relative thickness of the Patchawarra Formation; and [4] combining the structural and sedimentological interpretations to assess the implications for stratigraphic traps. Structural highs in the Caladan/Daralingie area are controlled by underlying pre-Permian topography that has been modified by glaciers around the Waukatanna, Moolalla and Daralingie Shelf. Post-glacial deformation is seen to influence the topography by severe erosional structures. This has affected the thickness of the Patchawarra Formation mimicking this undulating glacial terrain. Over time the sediments of the Patchawarra Formation compacted over the rigid basement structures creating drape structures. Glacial features including U-shaped valley, cirques and steep near vertical hills led to an application of a new modern day analogue in the North of Sweden. Toward the east, pre-Permian propagated reverse faults have been interpreted around Bobs Well. From this study, a better understanding on how to differentiate pre-existing structure and growth structures in the seismic data has made it possible to find potential relationships with structural and stratigraphic traps of hydrocarbons. Thicker stratigraphic sections of the lower Patchawarra Formation onlapping onto the glacial highs should be targeted in exploration as seismic reflections thin over these glacial features, producing stratigraphic pinch out.
Australian School of Petroleum
THE UNIVERSITY OF ADELAIDE

SA 5005 AUSTRALIA

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