This company operates Rowan Stavanger, which was working for Equinor on the Gudrun field when the incident occurred.
While testing the connection between the BOP and the high-pressure riser, the BOP’s blind shear ram (BSR) was blown out when the pressure reached 109 bar. Weighing about two tonnes, the ram first hit the railings in front of the BOP and then landed on top of a container used as a workshop outside the cordoned-off area. Nobody was inside the container or the cordoned-off area around the BOP when the incident occurred.
The direct cause of the incident was that the anti-rotation bar in the lock mechanism was in the wrong position after the BOP doors were closed.
A number of underlying causes for the incident on Rowan Stavanger have been identified. These relate primarily to:
- design of the lock mechanism – human-machine interface
- expertise of and training for personnel
- procedures and governing documents
- management of change (MOC)
- roles, responsibilities and sharing of information in the organisation
- workload and inclusion of personnel on board
- contractual requirements and pressure on costs
- the operator’s discharge of its see-to-it duty.
Actual and potential consequences
The incident caused a spill of drill water and hydraulic fluid to the weather deck on the Gudrun facility, and led to operational delays. Material damage to the BOP and the facility was limited.
However, the investigation team’s assessment is that the incident could have led to the loss of both primary and secondary barriers in the well if the lower pipe ram (LPR) had blown out during managed pressure drilling (MPD). Losing the LPR on the BOP could have caused a loss of well control with a big potential for harm to people, the environment and the facility.
The investigation team has identified nonconformities in the following areas:
- installations, systems and equipment
- lack of expertise on facility-specific equipment (NXT BOP)
- inadequate procedures and compliance
- lack of management of change (MOC) process
- unclear roles and responsibilities
- inadequate information-sharing
- inadequate organisation of work
- shortcomings in discharging the operator’s see-to-it duty
The PSA’s investigation has identified serious breaches of the regulations, and the following order has now been given to Valaris (Rowan).
Pursuant to section 69 of the framework regulations on administrative decisions, see sections 6 and 21 of the management regulations on management of health, safety and the environment and on follow up respectively, Valaris is ordered to do the following.
- Systematically review the company’s processes for managing change, including the system for ensuring facility-specific expertise and making provision for clear roles and responsibilities in the organisation, in order to ensure that the facility can be operated prudently in normal operation and in the event of hazards and accidents.
- Present a binding and scheduled plan for corrective measures which shows the priorities set for these measures and has a description of possible compensatory measures to be implemented until the nonconformity is corrected.
The deadline for complying with the order is 26 April 2021. We must be informed when the order has been complied with.