The Northwest Shelf of Australia is herein considered to be the part of the continental margin of Western Australia extending south westward to approximately lat. 22 °S and northeastward to approximately long. 131 °E (Figure 1). It was formed by a series of major tectonic episodes that began in the late Paleozoic and continued into the Cretaceous, and that resulted in the complete breakup of eastern Gondwana and the formation of the Indian Ocean.
Woodside Offshore Petroleum and its related predecessors have been Operator for the Northwest Shelf Joint Venture Group during more than 20 years of exploration in the region. Initially, the Group held exploration permits covering parts of all four basins of the Northwest Shelf, though these have now been substantially reduced. Most of the Joint Venture’s work has been centered on the Dampier area of the offshore northern Carnarvon basin, for which reason this chapter concentrates on the Barrow-Dampier subbasin. Discussion of the Beagle subbasin is included with that on the Barrow-Dampier subbasin because those two adjoining subbasins are similar in style. This is followed by a brief review of the Browse basin, in which the Joint Venture has also been active.
Only four wells have been drilled by the Joint Venture in the offshore Canning basin, the last one in 1971, and few wells have been drilled there by other operators. Warris (1973) summarized the geology and exploration history of the offshore Canning basin, and since then virtually no new work has been done in