Shell's FLNG facility moored offshore Western Australian has become notorious for the poor conditions faced by workers onboard.
Members of the union group The Offshore Alliance have made an official complaint to the offshore regulator, NOPSEMA, urging it to investigate alleged breaches of fatigue management standards.
The complaint, seen by Energy News, said the breaches occurred during planned operations and were not the result of employees carrying out emergency work.
It said service technicians have been sleep deprived during each condensate offtake, occurring around once a month, performed by Shell prior to July 2021.
Workers wake up between 3:00-4:30am, depending on their workscopes, finishing around 12 hours later and are unable to go back to their cabins to rest as they are usually occupied.
They instead sit in the lounge facilities, and return to work at 9pm and finish at 3am the following day before returning to work just two hours later.
Offshore Alliance said it had complained to Shell HR manager Simon White on June 25 - with White saying Shell was not going to investigate the Union's complaint.
"The breaches are systemic and the union believes that senior managers on Prelude have been aware of these breaches," the group wrote.
"It reflects the appalling OHS culture within a number of Prelude management. There are a large number of Shell managers who were aware of the OHS breaches over a long period of time and chose to say nothing and take no action to address the issue.
"It is only luck that there was not a serious accident or fatality during this period."
The Union said it understands there are log books/time sheets on the Prelude which would corroborate the worker's shift routines.
The complaint is just the latest in a litany of OHS concerns leveled at Shell over conditions onboard the facility, revealed by Energy News earlier this year.
Allegations have ranged from falling ice striking workers to the forging of rope-access documents.
The reports to NOPSEMA also reveal a raft of faulty equipment and poor construction quality onboard the facility.
A NOPSEMA spokesperson confirmed to Energy News it had received the latest complaint and is investigating.
Shell could not be reached for comment.
Prelude has finally almost reached its nameplate annualised rate of production of 3.5 million tonnes a year, however it was met with very little fanfare from either industry or Shell.
While the FLNG concept was meant to be a game-changer when it was proposed by Shell a decade ago, it is now trying to figure out how to wean itself off oil and gas, as a court-order ruled it must double its emissions reductions targets to 45% by 2030.
Shell has said it will appeal the decision but would also "rise to the challenge" to meet the new target.