Shell says its North Sea wells should not suffer Elgin-type gas leaks
11 September 2013
Royal Dutch Shell has said it is confident its North Sea wells will not fall victim to gas leaks similar to that at Total's Elgin field last March. Total warned Shell in early September that its Shearwater field may be at risk as a corrosive drilling fluid that is thought to have been involved in the Elgin leak is commonly used in similar wells such as Shearwater.
The fluids implicated in the North Sea's worst gas leak in 20 years at Elgin included calcium bromide, whcih are commonly used in such wells.
The Elgin platform leaked gas for more than seven weeks and cost Total around £1.6 million a day in relief operations and lost income.
Experts fear another leak, as operators turn to deeper, hotter and higher pressure fields to boost production. The North Sea is host to the highest number of high-pressure, high-temperature (HPHT) reservoirs of any mature oil and gas producing basin.
Like Elgin, Shell's Shearwater field is fed by a HPHT reservoir where temperatures can reach 140C.
However, a spokeswoman for Shell said the company did not use bromide-based fluids at the Shearwater oil and gas platform.
She added: "Shell is redeveloping the Fulmar reservoir from the Shearwater platform in line with UK regulatory requirements. We participate actively in industry knowledge-sharing fora and are confident in the safety of our well designs and operations."
Shell began a redevelopment programme for Shearwater in 2011. The redevelopment involves the abandonment of the original production wells and a drilling programme for the redevelopment of the Fulmar reservoir. It is expected to take several years to complete. Redevelopment was initiated, as part of normal field development, to access the remaining resources in the ground and maximise recovery.
Due to the incident in the Elgin field, Total reportedly plans to close at least ten other wells in the complex, as well as the one that leaked, which is expected to cost more than $2.34bn to replace.
Total UK chairman, Patrice de Vivies, told Reuters that when sharing information on the causes of the leak, he had cooperated with Royal Dutch Shell.
"With Shell we have shared even more as they have a neighbouring field, Shearwater, meaning they potentially have, perhaps, not identical, but similar problems," de Vivies added.
Elgin, which restarted in 2013, and Shearwater account for more than a tenth of British gas production. The field resumed output in March, but Total's investigation into the causes of the leak remain incomplete.
"We hope that the laboratory will be in a position by the end of the year to reproduce the phenomenon," de Vivies concluded.
Total chief executive, Christophe de Margerie, said: "The final conclusion hasn't yet been released because it is not yet over, and there are talks to understand everything that happened and everything that could happen in the future."
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