This incident occurred in connection with a diver-assisted subsea operation on the Alvheim field in the North Sea, operated by Marathon Oil Norge AS.
The underwater work was being conducted by diving contractor Technip Offshore Norge AS, using DSV Skandi Arctic.
A team of three divers were to be conveyed to the seabed work site in about 110 metres of water. The main umbilical was torn off during deployment of the diving bell on Skandi Arctic, leading to an escape of gas and loss of bell pressure.
The divers succeeded after 11 minutes in closing all valves to leak points inside the bell, and pressure was restored with the aid of the bell’s own gas reserve.
Pressure in the bell dropped the equivalent of 18 metres from an original level corresponding to 110 metres.
The incident did not lead to any known health consequences, but material damage was caused to the bell and the deployment system.
In the worst case, a failure to stop the leak from within the bell could have had fatal consequences for the three people inside it.
The PSA resolved to conduct its own investigation of the incident, in part to clarify the course of events and identify the direct and underlying causes.
One nonconformity from Norway’s petroleum regulations has been identified by the investigation.
This relates to Technip’s overall management of the business in connection with the operation of Skandi Arctic.