The UK’s regulatory body for safety, the Health & Safety Executive (HSE) has handed oil and gas super major, Shell, with an improvement notice, following an offshore gas leak earlier this year.
The leak occurred within the vicinity of the offshore Curlew Floating Production Storage Offloading (FPSO) vessel, an asset owned by Maersk Oil. Shell owns and operates the wells and subsea infrastructure that ties back to the Curlew FPSO.
The Curlew FPSO, is located in the offshore gas field of the same name, in the UK Central North Sea (CNS), close to the Shell owned and operated Gannet Field.
The HSE’s investigation found, that towards late 2014, Shell had made the decision to utilise the Pacific Dolphin, a Station Keeping Assist Vessel, to ensure the Curlew FPSO would stay on location during rough weather.
According to the HSE report, the decision was taken due to the concerns over the integrity of the FPSO’s own mooring lines.
During the 19th January, the line between the Pacific Dolphin and the Curlew FPSO became snagged around the Curlew fields subsea infrastructure.
In particular, the line is believed to have been snagged around a subsea isolation valve on the FPSO’s gas export pipeline.
As the line’s tension was increased, by the Pacific Dolphin crew in a bid to free it, the gas export line ruptured, allowing gas to be released to the surface.
No figure has been put on the amount of gas released, however the HSE has said that the incident had exposed “employees and others to a risk of fire and/or explosion”.
Due to bad weather on the day, Shell was unable to evacuate 50 offshore workers, as planned in such an incident.
In summing up, the HSE found that Shell had not fully ensured the Management of Change process was suitable, and assessment of risk sufficient thus putting the safety of their employees and other persons not in their employment at risk.