The Petroleum Safety Authority of Norway (PSA) has completed its investigation of the fire which broke out in the utility shaft on the platform Statfjord A on October 16, 2016, highlighting several areas for improvement for operator Statoil.
The fire began 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. It 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 result was an ignited hydrocarbon leak with a varying but limited leak rate. No people were injured during the incident, and the size of the fire was confined by the leak rate.
The PSA concluded that the incident did not have a major accident potential.
The investigation identified 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 operator company Statoil to explain how the nonconformities will be dealt with, and for an assessment of the identified improvement points.
The report is available here.