By OGJ editors
HOUSTON, Jan. 18 -- Statoil ASA said human error caused the natural gas leak that forced it to shut in production from the Snorre A platform and a satellite in the Norwegian North Sea Nov. 28, 2004.
The incident halted production of about 130,000 b/d of oil from the Snorre A platform and 75,000 b/d from its Vigdis satellite, which uses the Snorre A facilities for processing (OGJ Online, Dec. 2, 2004).
Statoil said its internal investigation following the loss of control over the well has been completed. The subsea template is still under investigation.
According to the inquiry report, the underlying causes of the incident were "inadequate planning and appreciation of the risk and a failure to observe governing documentation. The potential in the incident lay in the gas volumes, which leaked out and which could have been ignited," the company reported in a media release.
The direct cause, Statoil said, was "a suction effect which arose when an extra length of casing was pulled out and drew gas from the reservoir into the well. Passing via an external casing section which had suffered wear damage, the gas then escaped into the formation and out to the seabed."
Statoil on Jan. 11 notified Petroleum Safety Authority Norway (PSA) that it was able to resume partial production from the platform. The timing, the company said, would depend on PSA's consideration of Statoil's documentation and on weather because a remotely operated vehicle would monitor the start-up (OGJ Online, Jan. 11, 2005).