The hydrocarbon leak on the Statoil-operated Gudrun field occurred at 06:40 on Wednesday 18 February. Production was then shut down and the facility depressurised.
The size of the leak is currently not known.
No personal injuries resulting from the incident have been reported. There were 26 persons on board the Gudrun facility when the incident occurred, and 97 persons on board the West Epsilon mobile drilling facility close by.
The PSA has decided to initiate an investigation of the incident.
The objects of the investigation include clarifying the chain of events and identifying proximate and underlying causes.
The investigation will result in a report that will be published on ptil.no.