This date is a month behind the initial six-week timeframe afforded to fix the two thrusters, which blew in mid-September. At this time, Origin anticipated the vessel would be repaired by early November.

“The revised schedule of repairs and completion of sea trials will see the Safe Concordia arrive on location in the Bass Basin in mid December,” Origin said.

The vessel's owners, Consafe Offshore, said the rig was temporarily in Port Phillip Bay, south of Melbourne, for the replacement of faulty parts following a "partial breakdown of the transformers to the thruster power generation system."

The company said the costs were covered by the shipyard warranty.

The target date for first production from the Yolla A Platform is now December 31. Commissioning and performance and endurance testing of the production facilties, as well as non-critical rectification and maintenance work, Origin said.

“The vessel will remain on location during the commissioning period to ensure that commissioning activities are conducted expeditiously,” manager of investor relations Angus Guthrie said.

“The vessel is available for several months and this period may be extended if required under a number of options held by the joint venture.”

While Consafe Offshore repairs its vessel, work will continue on the BassGas project.

Guthrie said work at the onshore plant rectification work would be completed and commissioning would begin on some portions of the plant using processed natural gas from the Victorian grid.

Meanwhile, rectification work would also continue on the offshore platform using crews helicoptered in on a daily basis.

“These actions will ensure that the time required to complete works to allow the integrated commissioning of the onshore and offshore facilities once the Safe Concordia arrives is kept to a minimum,” Guthrie said.

BassGas is a partnership between Origin Energy as operator (42.5%), AWE (30%), CalEnergy (15%) and Mitsui subsidiary Wandoo Petroleum (12.5%)