The field has been developed with multiple production platforms, Statfjord A, B, and C, all of which have concrete gravity base structures that incorporate storage cells.
The oil spill was discovered during the loading of oil from the Statfjord A platform to the tanker Hilda Knutsen via the OLS B loading buoy, which is located between Statfjord A and Statfjord B.
Statoil said that tanker loading has stopped and supply to the pipe and loading system from Statfjord A has been closed, although the platform’s production is operating normally.
The leak is located in a flange in the loading hose. Statoil said that it was too early to say how much oil has leaked.
The stand-by vessel with oil spill response equipment and the anchor handling vessel, equipped with a ROV, are at the location. An SAR helicopter is also assisting with monitoring the spill.
The relevant authorities have been notified, the national oil company said.
This is not the first time a spill has been reported at the field. The Petroleum Safety Authority Norway investigated a hydrocarbon leak in the platform in September 2014. In December 2013, Statoil responded to a leak originating from platform A.
The Statfjord oil and gas field is located in both the Norwegian and UK sectors of the North Sea. Statfjord A began production in 1979, with Statfjord B following in 1982, and Statfjord C in 1985. The reserves, which consist of Jurassic-era hydrocarbon-bearing sandstones, are located at depths of 2,500-3,000 m (8,202-9,842 ft).