Tullow Ghana Limited and its partners have completed the first phase of the Turret Remediation Project on the Jubilee FPSO.
In a statement, Tullow announced that on behalf of the Jubilee Joint Venture Partners, the Interim Spread Mooring of the Jubilee FPSO, Kwame Nkrumah has been completed.
“This milestone involving the installation of an interim anchoring system on the stern of the FPSO to hold the vessel in place, completes the first phase in the Turret Remediation Project which will eventually provide the FPSO with a long term mooring solution,” Tullow said in the statement.
The turret on the FPSO connects the flexible pipeline fluid transfer system which helps in pumping the unprocessed oil to the FPSO for processing the export of the associated gas to the shore.
The bearing system is based on special rollers which can accommodate large coupling tolerances and relative deformations of load transmitting structures, while ensuring a passive (low friction) rotation and easy maintenance during the FPSO’s operating life.
The FPSO Kwame Nkrumah was hitherto moored using the turret bearing system which allowed the production platform to rotate throughout its lifespan, depending on the weather conditions.
The turret got damaged in February 2016 and after technical investigations it was detected that the extent of damage was critical and was no longer able to rotate as originally designed.
The operators realised that there was a problem with the rotation of the turret which affected the production schedule, leading to a drop in output and export of gas to shore.
They therefore employed a technique known as the Spread Mooring System as the best option, as compared to another option of hauling the FPSO back to the shipyard in Singapore or the nearest port that had the facility to receive the giant ship for maintenance.
According to the technical team that reviewed the options, the use of the spread mooring system was the excellent choice towards establishing the best long-term solution to the problem.
Tullow in its statement on Thursday explained that, in addition to the existing anchor lines on the FPSO’s turret, the FPSO is now firmly secured in position by six anchor lines, three on each side of the stern of the vessel allowing the three tug boats which have been keeping the FPSO in place over the last 11 months to return to shore.
It explained that phase of the project has been achieved with production maintained at optimal levels with the exception of short, planned reductions for technical reasons.
Oil and gas offtakes have also continued in the new normal state of operations, it added.
It said the JV partners are now analysing options for the next phase of the project which will involve modifications to the turret systems for long-term operations.
Detailed planning for these works continues with the JV Partners and the Government of Ghana, with final decisions and approvals being sought in the first half of 2017 and work expected to be carried out in the second half of 2017, it.
Commenting, the Managing Director of Tullow Ghana Ltd, Mr Charles Darku said: “It is a highly complex and significant achievement for an FPSO to be held to one heading by tugs within a few degrees for 12 months and for production to have been maintained throughout.”
“We would like to recognise the strong collaboration with our Joint Venture Partners, the Government of Ghana and our key contractors in achieving this important milestone,” he added.