The performance will be closely watched as the project, originally planned to produce first gas in 2014, entered its eighth year of construction two weeks ago.

The Gorgon domestic gas plant has been shut down since producing for 10 days in early August.

After the shutdown, a Chevron spokesperson told Energy News the company was undertaking system testing as a normal part of final commissioning.

Two weeks later the medium term capacity outlook for Gorgon on the WA Gas Bulletin Board run by the Australian Energy Market Operator was updated to state that Gorgon had no capacity due to "maintenance and modification of Barrow Island Domgas facility" and that this was expected to last until November 1.

If Chevron can restart production by November 1, the plant will have been down for almost 12 weeks after its brief 1.5 weeks of production in early August.

In response to questions about the modifications, a Chevron spokesperson said that after completing the initial trials of the plant "we are undertaking maintenance activities to ensure the system can reliably deliver domestic gas".

"Once the final export tests are successfully completed domestic gas supply to Western Australia will commence," the spokesperson added.

Chevron did not respond to questions on why modifications to the plant are required, what these modifications were and whether Gorgon will be able to commence supply in November.

Industry sources have confirmed that during the early August trials the gas delivered from Barrow Island to the Dampier to Bunbury Natural Gas Pipeline did have heavier fractions of gas entering the pipeline than is allowed by the DBNGP specification.

Domestic gas produced outside specification during commissioning can often be accepted by the pipeline operator by blending it with other gas that is within specification.

According to one industry source Chevron is not engaging with DBP, the operator of the DBNGP, to arrange for blending.

Busy on Barrow until Christmas

Work to complete the domgas plant modifications and commence domgas exports is only one of three milestones the Gorgon project is aiming to complete in 2016.

Last week The Australian cited Chevron CEO John Watson as saying Gorgon's first LNG train was now operating at over 85% capacity. Chevron claims in its September investor presentation that it will be at full capacity in the fourth quarter.

Watson was also reported as saying the second LNG train will start up this month.

This is consistent with what Chevron executive vice president upstream Jay Johnson told analysts in late July.

"We're incorporating all the experience gained from Train 1's construction, completion, and initial operations into Train 2 and Train 3," Johnson said.

"Construction on Train 2 and Train 3 is progressing very well. We expect first LNG from Train 2 early in the fourth quarter and from Train 3 in the second quarter of 2017."

If by years' end LNG train 1 is at full capacity, train 2 has started up and domgas is being exported, Gorgon will finally be starting to fulfil its promise more than seven years since sanction.