The first LNG carrier, the 160,000 cubic metre Asia Excellence, berthed at Barrow Island off Western Australia's Pilbara coast earlier this month as Gorgon's final commissioning phase ramps up.

Chevron Australian managing director Roy Krzywosinski said the commissioning cargo was critical for the final testing of critical systems and to efficiently cool down the plant prior to the start of LNG production.

"As the largest single-resource development in Australia's history, this is a significant milestone for Gorgon and is a testament to outstanding team work by our workforce, contractors and partners," he added.

Gorgon, also Chevron's biggest LNG project globally, will be a long-term supplier of natural gas to the US super-major's Asia Pacific customers and domestically thanks to Western Australia's contentious 15% gas reservation rule for every molecule of gas that hits WA's shores.

That rule may be WA's only saving grace in what Wood Mackenzie recently revealed to Energy News to be an expected 150 million standard cubic feet per day gas shortage come 2021 when the current supply contracts are due to be renegotiated.

Chevron is developing the Gorgon and Jansz-Io gas fields within the Greater Gorgon area, between 130 and 220km off WA's northwest coast.

It includes the construction of a 15.6 million tonne per annum LNG plant on Barrow Island and a domestic gas plant with the capacity to supply 300 terajoules of gas per day to WA.

Gorgon LNG will be off-loaded via a 2.1km loading jetty for transport to international customers. The domestic gas will be piped to customers on the WA mainland.

Chevron had hoped to ship Gorgon's first cargo last year after missing its original target of 2014 when the project was first approved in 2009.

Now it expects the maiden cargo to leave the newly built facility on Barrow Island before March 31.