US energy giant Chevron has sealed binding sales deals with Tokyo Electric Power Company for liquefied natural gas from its Wheatstone project off the WA coast.

The companies are also in talks about TEPCO purchasing an equity share in the titles covering the Wheatstone fields and a percentage of Chevron's share of the Wheatstone downstream processing facilities.

TEPCO, the company that operates the stricken Fukushima nuclear power plant in Japan, has agreed to buy up to 3.1 million tonnes per year of LNG from Wheatstone for up to 20 years.

Chevron Gas and Midstream president John Gass welcomed TEPCO as a foundation customer and potential investor in Wheatstone.

Chevron Australia managing director Roy Krzywosinski said the company had completed the front-end engineering and design phase for Wheatstone with a final investment decision on track for later this year.

“The TEPCO agreements and other LNG agreements we are finalising give Wheatstone great momentum,” he said.

“The Ashburton North site earmarked for the LNG processing plant is ideally located to unlock the significant gas resources in the western Carnarvon basin.”

Wheatstone, which will be one of Australia’s largest resource projects, will consist of two liquefied natural gas trains with a combined capacity of 8.9mtpa and a domestic gas plant.