The binding sales and purchase agreement covers 27% of the project's targeted nameplate capacity of 15.6MMtpa over that timeframe with Chevron saying more than 75% of its equity LNG from Gorgon is committed to Asian customers.

Chevron gas and midstream president Pierre Breber said the contract was an important step in the commercialisation of its Australian gas holdings and represented further diversification of the company's sales portfolio.

"We are pleased with the opportunity to supply LNG to South Korea and look forward to building lasting relationships with our customers in the region as the Gorgon and Wheatstone projects move into operations," Chevron Australia managing director Roy Krzywosinski said.

"South Korea joins our existing strong LNG customer base and demonstrates the Chevron-led Gorgon and Wheatstone projects are well-placed to meet the growing demand for natural gas in the Asia-Pacific region."

The three-train Gorgon LNG project on Barrow Island is targeting first LNG production in mid-2015 with the joint venture comprising of Chevron (47.3%) ExxonMobil (25%), Royal Dutch Shell (25%), Osaka Gas, Tokyo Gas and Chubu Electric Power, which each have a holding of less than 2%.

On the Pilbara coast 12km west of Onslow, Wheatstone (Chevron 64.14%) is targeting 8.9MMtpa of capacity with first exports in 2016. Woodside agreed to buy a 13% stake of the project under a $3.4 billion, multi-asset deal it struck with Apache Corporation in December.

This project already has approval to expand to 25MMtpa.