Norwegian energy firm Statoil has discovered between 30 million and 80 million barrels of recoverable oil near its operating Grane field in the North Sea.

The 25/8-18 S well proved a 25m oil column in the D-structure of the Heimdal Formation.

The Transocean Leader rig was used to drill the well, which is located in PL169 in the North Sea.

Statoil vice-president for exploration in the North Sea May-Liss Hauknes said: "We are pleased with having proved new oil resources in the Grane area.

"Near-field exploration is an important part of Statoil’s exploration portfolio on the Norwegian continental shelf.

"It provides high-value barrels that are important for extending the production life of existing installations."

The D-structure is situated on the Utsira High, just 7km north of the Grane field, near the Grane F oil discovery made by Statoil in 2013.

"We are pleased with having proved new oil resources in the Grane area."

Statoil said the D-structure was originally penetrated in 1992 by well 25/8-4, which encountered just one metre of oil corresponding to around six million barrels.

The 25/8-18 S is the fourteenth exploration well drilled in production licence 169. It was drilled to a vertical and measured depth of 1,863m and 1,867m below the sea surface.

The Transocean Leader rig will now undertake permanent plugging of discovery well 25/11-16 (Svalin), also in PL169.

Statoil operates PL169 with a 57% interest. Petoro and ExxonMobil Exploration & Production Norway own 30% and 13% stakes in the licence, respectively.

Image: The Transocean Leader drilling rig. Photo: courtesy of Harald Pettersen.