Petroleum Industry in Western Australia - Geology

Geology

Five of the seven major sedimentary basins in Western Australia have known hydrocarbon accumulations,with 2007–08 production coming from the Carnarvon, Perth, Bonaparte and Canning basins. Sixty-one fields were on production during 2007–08 fiscal year. Petroleum in Western Australia is mostly sourced from the Carnarvon Basin, which stretches for 1,000 km of the west and northwest coast, from Geraldton to north of Port Hedland. In area, the onshore part of the Carnarvon Basin covers about 115,000 km² and the offshore part covers approximately 535,000 km² with water depths up to 3,500 m.

Less than 5% of the state's gas comes from fields near Dongara, part of the Perth basin, which extends about 1300 km along the southwestern margin of the continent. This is a large (172,300 km²) basin that formed during the separation of Australia and Greater India in the Permian to Early Cretaceous period. It includes a significant onshore component and extends offshore to the edge of continental crust in water depths of up to 4500 m. The Officer basin, straddling the WA-SA border in the south-east section of the state, is a poorly explored basin, with limited seismic coverage, although more than 20 exploration wells have been drilled. A small amount of oil is produced in the Canning basin, in which 250 wells have been drilled and 78,000 line-km of 2D seismic surveys has been shot. A local company, Arc Energy, currently the largest Perth basin producer, is actively exploring and drilling in the Canning basin.