Shell has admitted that its strategy for inspecting and maintaining oil pipelines has failed and must be improved, as it continues to battle an oil leak in the North Sea.
“Our inspection and maintenance programme for pipelines has let us down, and we need to strengthen it,” a Shell spokesman said. “We will be making every effort to improve and strengthen our inspection programme.”
Shell is now facing a new problem in that the flowline is experiencing buoyancy, after it was depressurised in an attempt to decrease the leak rate. Shell will today try to secure the flowline using rock mattresses.
Divers and remotely operated vehicles (ROVs) have been deployed to remove panels and gratings so that the ability to close the valve safely can be assessed. Shell is also looking at containment options as a longer term solution.
Shell technical director Glen Cayley said: “We are working towards a swift solution. However, I cannot stress enough the need to undertake detailed risk assessments and ensure any work considered is undertaken safely.”
It is not known how much oil has leaked into the North Sea, but Greenpeace has made an estimate of 100t, and the BBS reported estimates of “more than 200t”. 660t of oil are thought to still be inside the leaking flowline.
The flowline that has leaked is around 20 years old, and should typically have a lifespan of 25 to 30 years — but a Shell spokesman said the “operating conditions that we experience in the field” could “materially impact the operational lifetime of the equipment”.
Shell will commence a planned shutdown of its Gannet platform for 30 days from today, and will use the opportunity to inspect other pipelines. The company said it has been constantly monitoring the leaking flowline since the incident was reported last Wednesday.