The Petroleum Safety Authority Norway (PSA) has completed its investigation of gas leaks on the Statfjord B facility on 23 May 2022. The investigation has identified serious breaches of the regulations, and Equinor has now been given an order.
Comprising two leaks on Statfjord B, where Equinor is the operator, the incident occurred in connection with running up after a turnaround. The leaks came from holes in two pipelines used for blowdown/pressure relief in process area M10T.
These leaks are estimated to have had initial rates of 0.52 and 0.57 kilograms per second respectively, with a total emission of about 285 kilograms of export gas.
Actual and potential consequences
The incident’s actual consequence was gas leaks with consequent shutdown, emergency response mobilisation and a delay of just under two days in restarting the facility.
No significant material damage was suffered except to the already degraded blowdown lines. No personnel were injured.
Under different circumstances, the gas leaks could have had greater consequences and lives might have been lost.
Direct and underlying causes
The direct cause of the leaks was external corrosion and consequent loss of integrity. Both pipes were probably corroded through before the incident occurred
Underlying causes are complex, with failure to carry out maintenance as a crucial factor. The investigation indicates a number of reasons why the necessary maintenance was not executed.
The investigation shows that this incident could have been avoided if Equinor had established a robust system for following up and maintaining control of the integrity of the blowdown lines.
Nonconformities
The investigation has identified seven nonconformities, related to
- management of HSE
- knowledge of weaknesses in barriers and barrier elements
- marking of equipment
- maintenance
- maintenance programme
- maintenance criteria
- maintenance efficiency.
In addition, seven improvement points have been identified, related to
- assessing the HSE consequences of manning changes on Statfjord B
- assessing the HSE consequences of manning changes in the onshore organisation for Statfjord B
- ensuring competence (training backlogs)
- activating deluge
- plans for running up the facility after a turnaround
- evacuation measures
- ensuring appropriate behaviour.
