Production from one of its two wells was suspended due to problems with the swivel on the FPSO connecting the flowlines of the ship with the internal mooring buoy.
Tap said in a statement that current operations involve designing and fabricating pipe-work modifications to re-establish production from the #2 well.
In the meantime production from the Woollybutt field is continuing at rates of around 28,000 bopd from the #1 well down from its peak of 40,000bopd.
Production was initially expected to be down for 2-4 days while the cause of problem is fully evaluated. It is now anticipated that the latest modifications will be take around 4-6 weeks.
Located 50km southwest of Barrow Island and 42km northeast of the Griffin oil field, the 'Four Vanguard' is operating the Woollybutt-2AST3 and Woollybutt-1ST1 wells, with an estimated proven and probable recoverable reserves around 25 million barrels.
Participants in WA-234-P include Tap Oil 15%, Eni Australia (operator) 65% and MOBIL Australia Resources 20%.