The timing of the giant floating facility's return to operations is likely to coincide with peak consumption in major markets, including China and Europe, as winter in the northern hemisphere drives demand, although high inventories have limited buying so far this year.
In a sign that the work, which started in August, is near completion, the LNG tanker Symphonic Breeze has been booked to arrive at the floating facility on Dec. 6, shipping data shows.
Shell declined to comment directly on the status of the maintenance. The British company said last month that it expected the plant to ramp up production in December.
"Prelude is a complex facility in a remote offshore location. This is its first major turnaround and we continue to work through the process methodically taking as much time as required to ensure safe execution of all activities," Shell said in a statement.
"During the turnaround, additional scopes of work were identified and a decision made to extend maintenance to complete these scopes ahead of restart."
Two sources familiar with the facility's operations, speaking on condition of anonymity, said the maintenance was nearly complete, with one saying Prelude was expected to restart next week.
Prelude, whose deck is longer than four soccer fields, was the world's first floating LNG facility to use novel technology and cost over $12 billion, according to estimates.
The facility, some 475 kms (300 miles) off the west coast of Australia, has suffered several outages since it started production in June 2019, including a fire that led to a full power loss in December 2021.
Reuters reported in September that Shell considered shutting Prelude for a year to fix issues, but instead opted for a shorter maintenance period.
