Norway’s Petroleum Safety Authority (PSA) has identified regulation breaches following its investigation into a fire that broke out on Statoil’s Statfjord A platform in October 2016.
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Statfjord A. Image from Statoil. |
The fire occurred on 16 October, and began in the utility shaft during the transfer of oil from the platform’s storage cells to a shuttle tanker.
According to the PSA, the actual consequence was an ignited hydrocarbon leak with a varying, but limited leak rate. The PSA has concluded that the fire, which was confined by the leak rate, would not have escalated even with a long-lasting leak, given that the fire water system functioned.
Although there were no injuries reported, and the incident did not have a major accident potential, the PSA’s investigation did identify three nonconformities and four improvement points.
The nonconformities related to investigations and improvement measures after earlier incidents, maintenance of shutdown valves, and blocking of safety systems.
Improvement points relate to alarm texts, conflict of roles in the emergency response organization, expertise and training, and general alarm and establishing of the emergency response organization.
The PSA has asked Statoil to explain how the nonconformities will be dealt with, and for an assessment of the identified improvement points.
The fire
In December, Statoil completed its internal investigation on the fire, which occurred at 8:20 a.m. local time, was out by 11 a.m. About 20 of the 67 staff on board were moved to the nearby Statfjord B facility by helicopter during the incident and production on Statfjord A shut-in.
According to the PSA’s investigation, which was launched on 17 October, thefire began in the utility shaft on the Statfjord A facility during transfer of oil from the platform’s storage cells to a shuttle tanker.
One of the loading pumps continued to operate because a shaft in the circuit breaker intended to shut off power to its motor suffered a fatigue fracture.
However, displays in the control room indicated that the pump had stopped. As a result, crude oil was pumped for 51 minutes against a closed valve and its temperature rose from 33°C to 344°C.
The high temperature combined with powerful vibration in the pump meant that crude oil eventually leaked through the pump seals and ignited. In addition, fire broke out in crude oil which had leaked into an insulation box connected to the seal oil system.
The fire was confined by the quantity of oil, which leaked out. The fire was initially detected by a flame detector on the loading pump deck, and eventually extinguished through activation of the deluge system in the room.
The Norwegian part of the Statfjord field is in Blocks 33/9 and 33/12 in license 037. It is one of the oldest producing fields on the Norwegian Continental Shelf, and the largest oil discovery in the North Sea. It is expected to continue producing until at least 2025.
The field has been developed with the Statfjord A, B and C production platforms. Statfjord A is a production platform that has a concrete substructure and storage cells. It began production on 24 November 1979. Statfjord B followed on 5 November 1982, and Statfjord C on 26 June 1985.
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