OSLO, May 25 (Reuters) - Norwegian oil firm Statoil said on Tuesday the problematic well that shut the North Sea Gullfaks C platform had still 'unstable' pressure and that it was still unknown when the platform would resume operations.
'The pressure is still unstable, but controlled,' Statoil spokesman Gisle Johanson said. 'We have no information on how long before normalisation of production.'
Statoil said on Friday it had evacuated and shut the Gullfaks C platform in the North Sea after changes in well pressure led to a fault on one of two valves designed to prevent a blowout.
A leading Norwegian green group, Bellona, has said the situation was 'very critical' and highlighted continued risks of offshore oil and gas exploration in the wake of BP's well blowout and environmental disaster in the Gulf of Mexico.
Gullfaks has seen its production curtailed by some 60 to 70,000 barrels of oil equivalent per day, Statoil said, down from a production of 78,000 barrels of oil per day and 420 million standard cubic metres of gas per year.
Statoil said that satellite fields Tordis and Gimle were also shut. Tordis produces 46,000 barrels of oil per day and 50 million standard cubic metres of gas per year. Gimle produces 10,000 barreld of oil per day.
Gullfaks C is one of three platforms at the site, which handle oil and gas from the Gimle, Tordis, Vigdis, Visund, Gullfaks and Gullfaks Soer fields.
Some 90 people were evacuated from the platform, with about 126 essential personnel still onboard.
'We will have reduced manning until the situation is normalised,' Johanson said.
The sea depth at the site is 130 to 220 metres, with the reservoirs 1,700 to 2,000 metres below the sea level.
Statoil owns 70 percent in Gullfaks, with Norwegian-state owned firm Petoro the minor partner with 30 percent.
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