Wind force of 43-60 knots and 17-18 metre waves have been reported in the area where the incident took place. The wind is now declining.
The evacuated crew members were transported by helicopter to Heidrun. No-one has been hurt, and the rig is now reported to be stable. Six of the original 86-member crew are Norwegian, of which four are among the 63 crew members who are still on board.
Ocean Vanguard is drilling on well 6406/3-1 and had not reached the reservoir when the accident took place. There is therefore no immediate danger of discharges of oil or emissions of gas. There had been a check of the disconnected drillstring before the riser was torn off.
The PSA takes a serious view of the incident, and has started work to investigate and assess the circumstances in connection with the accident.
A formal investigation group will be established in the PSA during the course of the day.
Ocean Vanguard is owned by the American rig company Diamond Offshore.
Contact person in the PSA: