New maps to improve offshore basin structural interpretation

03 March 2011

The survey ship MV Duke towing a sensor off Western Australia. Copyright CGG Veritas

The survey ship MV Duke towing a
sensor off Western Australia.
Copyright CGG Veritas

Companies involved in offshore petroleum and energy exploration will be better able to interpret geological structures when evaluating prospectivity in parts of Australia's western and eastern coasts following recent work undertaken by Geoscience Australia.

As part of its Offshore Energy Security Program, Geoscience Australia has produced new gravity and magnetic maps of the Mentelle, North Perth and Southern Carnarvon Basins and Wallaby Plateau off Western Australia and the Capel and Faust Basins in Australia's eastern marine jurisdiction.

These maps, which combine data from surveys conducted over several decades, have minimised the distortions caused by data mismatches.  This occurs when the survey passage of one ship crosses the collection path of another. The mismatches arise from instrument drift, inconsistent data processing, differing reference systems and particularly from positioning errors which were prevalent in surveys conducted prior to the development of the Global Positioning System (GPS).

Geoscience Australia has reduced this mismatch problem by levelling, or adjusting line data to minimise crossover errors and provide a refined dataset suitable for gridding and further image processing.

In future, explorers will have a better understanding of the geological architecture of the regions to identify potentially resource-rich offshore sedimentary basins in which petroleum occurrences may be found in the remote eastern and the southwestern areas of Australia's marine jurisdiction.

Topic contact: Last updated: October 4, 2013