OSLO, Norway – The Norwegian Petroleum Safety Authority (PSA) has ordered Equinor to take action following an investigation of two gas leaks on the Statfjord B platform in the North Sea last May.
The leaks, which occurred during running up operations after a turnaround program, issued from holes in two pipelines used for blowdown/pressure relief in process area M10T.
The PSA estimates the initial rates at 0.52 and 0.57 kg/sec, with about 285 kg of export gas emitted in total. Equinor subsequently ordered a shutdown and emergency response mobilization, with the facility restarted two days later.
Although no significant damage occurred except to the already degraded blowdown lines, and no injuries resulted, this might not have been the case under different circumstances, the investigation concluded.
The direct cause of the leaks was found to be external corrosion and consequent loss of integrity, with both pipes likely corroded through before the incident occurred. Among the underlying causes, failure to conduct maintenance was seen as critical.
According to the investigators, the incident could have been avoided if Equinor had established a secure system for following up and maintaining control of the integrity of the blowdown lines.
Seven nonconformities came to light, related to management of HSE; knowledge of weaknesses in barriers and barrier elements; marking of equipment; maintenance; the maintenance program and maintenance criteria; and maintenance efficiency.
In addition, the PSA found seven improvement points. Equinor must now ensure maintenance of hydrocarbon pipes in carbon steel on Statfjord B so it can perform as required through all production phases. And the company must verify that its maintenance program for hydrocarbon pipes in carbon steel contains activities for monitoring performance and technical condition, to ensure that failure modes are identified and corrected.
Deadline for response to the non-conformities is June 1, 2023.