The oil spill on the Statoil-operated Norne field in the Norwegian Sea on 23 November was larger than first assumed.
Statoil's calculations now show that about 2,140 barrels (340 cubic metres) of oil were discharged. The first estimate by Statoil, based on observations by its own helicopter and by the Norwegian National Coastal Administration's surveillance plane, was 280 barrels (45 cubic metres).
"The previous estimate was calculated according to the dimensions of the slick," says Jostein Gaasemyr, operations vice president for Norne. "The new estimate is based on data from the incident logs on board the Norne ship."
"We take a very serious view of this incident."
The discharge was associated with the shutdown of the facilities on board, in connection with modification work in the process control system. Preliminary findings indicate that the discharge occurred as a result of a fault in the facilities. This led to oil entering the system which treats produced water. From there, the oil reached the sea.
Due to unfavourable weather conditions it was not possible to collect the oil.
The area was monitored by helicopter daily until 4 December. No oil has been seen on the surface since 24 November. Nor do satellite pictures show any indications of an oil spill. As a precautionary principle, monitoring will continue.
Statoil, in collaboration with the Sintef research foundation, is evaluating whether the discharge will have any impact on the environment.
An inquiry team is currently working to find out all the factors relevant to the incident.
The matter has been reported to the Petroleum Safety Authority Norway and the Norwegian Pollution Control Authority (SFT).