More than 200 exploration wells had been drilled in the Barrow sub-basin by the end of 2001, including West Tryal Rocks in 1972, and Spar in 1976 - both discovered by West Australian Petroleum (WAPET) which had been a pioneering company in the development of the Western Australian petroleum industry. WAPET was the operator on behalf of various joint ventures comprising Chevron, Texaco, Shell and Ampolex (the exploration division of Ampol). Chevron and Texaco merged in 2001, Mobil took over Ampolex, and later merged with Exxon to form ExxonMobil. In 2000, Chevron became the operator of all WAPET's petroleum assets.
