Although the agency said that the incident “did not have a major accident potential” factors such as the small nature of the leak that led to the fire and the platform’s response systems, the PSA identified several nonconformities and improvement points.
A fire began in the utility shaft on the Statfjord A facility on Oct. 16, 2016, while oil was being transferred to a shuttle tanker. The agency explained that 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 (91°F to 651°F).
The high temperature combined with powerful vibration in the pump meant that oil eventually leaked through the pump seals and ignited. In addition, fire broke out in the 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 PSA said. 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. It concluded that the fire would not have escalated even with a long-lasting leak due to the functional deluge fire extinguishing system.
None of the 67 people onboard was injured during the incident.
As a result of the investigation, three nonconformities and four improvement points were identified. 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 said.
The safety watchdog has asked operatorStatoil to explain how the nonconformities will be dealt with, and for an assessment of the identified improvement points.
In addition, PSA has authorized Statoil to use the semisubmersibleSonga Enabler to drill a fourth production well at the Snøhvit gas field in the Barents Sea. The well template is in 318 m (1,043 ft) of water; drilling is scheduled to begin later this month and will last 65 days.
In July 2016, Statoil received consent to use the CAT-D semisubmersible to drill three wells on the field. The PSA said that the fourth well is to be drilled in the same well template as two of the first wells.
In October 2016, Statoil announced it would suspend the contract after the rig completed its current well on Snøhvit. At that time, it said the rig should resume drilling early this April with a well on the Blåmann prospect, but that the company was working to revise the existing drilling schedule with a view toward the earliest possible date for resumption of work.
Located northwest of Hammerfest, Snøhvit has been developed using a subsea production facility. The gas is transported onshore through a 143-km (89 mi) pipeline to Melkøya. Production began in 2007.