An oil sheen has been reported in the North Sea 160km North East of St Fergus approximately 3.7 km from the pipeline connecting the Galley subsea field to the Tartan Alpha Installation, which are both operated by Talisman Energy (UK) Limited. It was first observed at 13.50 on Tuesday 28 August and size of the sheen was estimated to be between 32 tonnes and 132 tonnes of oil. Aerial observations today (29 August) at 14.35 hours estimated between 5 tonnes and 34 tonnes of oil.
On 24 August Talisman reported a minor leak from the Galley subsea field to Tartan Alpha Installation pipeline. This is a 26 km pipeline in a water depth of 147metres which transports produced fluids from the Galley field for processing on the Tartan Alpha installation.
Talisman has stated that the hydrocarbon content of the fluid isolated in the pipeline was approximately 14-15%. At the time the leak was identified the pipeline was depressurised and isolated. DECC were notified of this release and Talisman monitored the leak point using a remotely operated vehicle. The leak rate of emulsified fluid containing oil, gas and water was estimated at 4 kilograms per hour. The total fluid released from the Galley pipeline has been reported to DECC as approximately 14 tonnes of which 2 tonnes is oil.
On 28 August Talisman were preparing to commence flushing of the Galley subsea pipeline to the Tartan Alpha platform, when the oil sheen was spotted by a surveillance aircraft.
The source of the sheen has not been identified and samples of the oil have been taken for analysis. At this time there is no evidence to indicate an ongoing release of oil. Nearby installations contacted by DECC confirmed that no potential sources of the sheen (topside or subsea) had been identified. Talisman are reporting that the source of the oil is not related to the Galley subsea pipeline.
The Maritime and Coastguard Agency and Marine Scotland have both been notified and DECC will continue to monitor and investigate the situation. The incident will be subject to a full investigation by DECC.