New frontiers in old areas: petroleum potential of Precambrian of Australia

More than 1 million km/sup 2/ of Australia is underlain by Proterozoic sedimentary basins, but few exploration wells have been drilled in these basins. Most wells drilled have tested the late Proterozoic sequences of central Australia. In the Amadeus basin, gas and some oil shows have been intersected in the Ooraminna and Dingo wells. The late Proterozoic sequence in the Officer basin also contains oil or gas shows. Only one exploration well (Broadmere 1) has been drilled in the McArthur basin of northern Australia, the results of which were disappointing. However, a series of shallow holes drilled by the Bureau of Mineral Resources (BMR) intersected thick sections of organic-rich sediments, some of which are within the oil-generating zone. Live oil was encountered in the BMR Urapunga 4 well in the Velkerri Formation, a unit dated at 1.4 to 1.7 Ga. This oil, which may be the oldest found in the world, not only upgrades the petroleum prospectivity of the McArthur basin, but also of the Victoria River basin to the west and adjacent middle Proterozoic subbasins. Results from the McArthur basin and from exploration in the Amadeus and Officer basins suggest that upper and middle Proterozoic basins should not bemore » overlooked when considering Australia's petroleum potential.« less