ABERDEEN, UK – Shell says there have been no further oil leaks from the Gannet field flowline in the UK North Sea, nor from the relief valve which divers closed last Friday.
The company is conducting continuous monitoring to make sure no releases have occurred.
A reconnaissance flight on Tuesday evening identified no sheen on the sea surface, although small sheens have appeared periodically as a result of dredging to establish the source of the original leak. However, these have quickly dissipated.
So far 72 concrete mats have been placed on the flowline, and all buoyant sections of the pipe are now secured to the seabed. More mats will be laid over the next few days.
Shell has also started to evaluate options for evacuating the remaining mix of gas, oil, and water in the pipe, a process expected to take weeks. Once the review is completed, plans will be submitted to the UK Secretary of State’s Representative Hugh Shaw for approval.
Shaw, appointed by the government to oversee the operation, said: “The risk of further oil release has considerably reduced following a successful operation to return raised sections of the pipeline to the seabed with concrete mattresses. The latest survey shows a few sections are lying just above the sea floor but operations continue to add additional mats to reduce the risk further.
“A slight sheen was reported in the area yesterday morning and I believe it is inevitable that further sheens will be seen as we move to the dredging and inspection phase of the operation and oil is released from sediment on the sea floor.
“Dredging and inspection operations to try and ascertain the precise source of the original leak commenced earlier today. Weather permitting, these operations may take three to four days to complete.”