"The well is stable like yesterday, there is no pressure in the well, but it still has to be secured," said Oivind Reinertsen, Statoil senior vice president of the Tampen area in the North Sea, where Snorre and Vigdis are located.

In the British sector, the Brae oil and gas complex remained closed as work continued to repair a gas leak found at the weekend, operator Marathon said.

The closure reduced UK North Sea oil production by about 76,000 barrels a day (bpd) of which 36,000 bpd came from Brae and the rest from four other fields which use the Brae intrastructure. Gas output was cut by about 850 million cubic feet a day (mmcfd).

The two shutdowns have helped pushed up international oil and natural gas prices. North Sea Brent futures rose more than a dollar on Monday and were up another 15 cents at $45.90 a barrel on Tuesday.

STARTING WORK

Norway's Statoil said that work will start on Tuesday to inject cement into the well to secure the formation. "In a few days, that work should be completed. After that, we will work out a plan to restart production," the spokesman said.

Most crew members were evacuated from Snorre A to nearby platforms on Sunday night when operator Statoil detected a gas leak from a well. The leak was halted on Monday.

Most gas at Snorre A, a steel-hulled production, drilling and quarters unit which is anchored to the seabed by tethers, is reinjected into the well. Oil is piped to Statoil's Statfjord A platform where crude is loaded onto shuttle tankers.

Norway is the world's number three oil exporter after Saudi Arabia and Russia, producing about three million bpd.

The Brae complex produces about 500 mmcfd but the shutdown has also halted gas exports to the UK from Norway's Heimdal gas processing plant which uses the Brae facilities. Heimdal produces around 350 mmcfd but this can rise to 455 mmcfd.