An oil release from a pipeline in Shell’s Gannet F development, totalling approximately 218 tonnes1 occurred during the period from 10 to 19 August 2011. The oil dispersed naturally well away from the shore and the UK-Norway median line and there has been no evidence of any significant environmental impact to date resulting from this release.
An oil sheen on the sea surface was observed by Shell personnel on Wednesday 10 August, and my Department was notified on the same day that a leak had occurred. A DECC inspector was in regular communication with Shell from that point. On the evening of August 11, DECC was notified that the release had stopped. However, Shell provided DECC with further aerial surveillance information late on the afternoon of Friday 12 and it became clear that the release was continuing and that there was potential for significant pollution. The Secretary of States representative for maritime salvage and intervention (SoSREP) was immediately notified and he mobilised to Shell’s headquarters on Saturday 13 August. A team from DECC and Marine Scotland was assembled at Shell’s offices to attend an operations meeting that afternoon, with the SoSREP formally establishing an operations control unit at Shell’s office at 9 am on Sunday 14 August.
The role of the SoSREP is to represent the Secretaries of State for the Department of Energy and Climate Change (in relation to offshore installations) and the Department for Transport (in relation to ships) to ensure the risk to safety, property and the UK environment arising from accidents involving ships, fixed or floating platforms or sub-sea infrastructure is eliminated or effectively reduced.
In the case of an offshore oil release, the SoSREP monitors the operator’s response to a pollution incident and, if he deems necessary, has powers to give directions and to take such other actions as may be required where there is or may be a risk of significant pollution. The SoSREP is empowered to make crucial and often time-critical decisions, without delay and without recourse to higher authority, where such decision are in the overriding public interest. The SoSREP has been in close contact with DECC and the Scottish Government Ministers throughout.
On 14 August, a survey by a remotely operated vehicle confirmed that the initial leak had been stopped, but a second, smaller, leak was continuing. The survey also discovered that the pipeline bundle, within which the oil flow-line was contained, had lifted from the seabed in a number of places. Action to halt the continuing small leak had to be deferred until the pipeline could be stabilised. With the approval of the SoSREP, Shell partially stabilised the pipeline by laying concrete mattresses on it, and the second leak was then halted on 19 August.
The operations control unit remains in place and the SoSREP is continuing to work with Shell as they develop plans to remove the remaining inventory in the pipeline (estimated at 660 tonnes of oil).
Although this incident is in no way comparable with major pollution incidents such as the gulf of Mexico—in the case of Macondo it is estimated that 4,900,000 barrels of oil were released to sea, the Gannet release equates to 1,300 barrels—this is nevertheless the largest oil release on the UKCS in over a decade.
My Department and the Health and Safety Executive have commenced investigations into the cause of the incident, which are likely to take some months. A full report will be sent to the procurator fiscal to consider whether a prosecution is appropriate.
1It is difficult and takes time to get an accurate assessment of the size of a release and this is subject to ongoing revision.