The three-digit net pay find occurred in the Triassic Mungaroo Sands in 968m of water.
The discovery well is located in WA-392-P (Chevron 50%, Shell 25% and ExxonMobil 25%) - about 95km northwest of the under construction Gorgon LNG plant on Barrow Island.
"This discovery is a continuation of our exploration success and further positions our company as a key supplier for future liquefied natural gas demand in the Asia-Pacific region," Chevron Asia Pacific Exploration and Production president Melody Meyer said.
Chevron Australia managing director Roy Krzywosinski was also pleased.
"This discovery in the Greater Gorgon Area is an important addition to our portfolio and highlights the industry-leading results of our exploration program in Australia," he said.
The successful well also completed the second year work commitment for the permit.
Chevron engineers have investigated Gorgon project expansion opportunities for years, although the oil price downturn has impacted further investment prospects industrywide.
The existing $US54 billion ($A67.6 billion) Gorgon project is targeting 15.6 million tonnes per annum of LNG capacity with first cargoes expected before year-end.
The Gorgon joint venture comprises Chevron (47.3%) ExxonMobil (25%), Royal Dutch Shell (25%) and Osaka Gas, Tokyo Gas and Chubu Electric Power, which each have a holding of less than 2%.
