Oil and gas production is expected to resume from the Visund platform in the North Sea in mid-June. Tests and repair work following the gas leak on 19 January will then be completed.
Statoil is now working to verify the technical condition of the process plant on Visund. This calls for thorough inspection and control of the facility. Production will not start up again until the Visund management team is confident that it can be resumed safely.
The knock-out drum, one of the gas coolers and the flare tip were subjected to considerable force during the gas leak. This equipment will therefore be checked and analysed particularly thoroughly, and all further use will take place with a good safety margin.
Further analysis and control of the condition of the flare tip is necessary, along with some minor modifications. The flare's piping system is being repaired, and the flare and seawater systems are being comprehensively tested for pressure and leaks.
A metal plate positioned at the flare tank's outlet to the knock-out drum collapsed, causing the damage and the gas leak. Its function was to change the gas flow in the tank in order to collect liquids before the gas was piped to the flare.
This component was deformed by aerodynamic forces as the gas flowed through, creating a build-up of pressure in the knock-out drum. A portion of the plate came loose and was carried in the gas flow into the flare piping. It created a hole about 50 centimetres in diameter in the pipe, where gas streamed out in an uncontrolled manner.
The total daily loss of output from Visund is roughly 35,000 barrels of oil and about five million cubic metres of export gas. Statoil's share is 32.9 per cent.
The field has been producing oil and gas since 1999, and Statoil took over as operator from Hydro on 1 January 2003.