The discovery was made in the “Polynya Tubåen” prospect (7220/7-5). The well was drilled by the COSL Prospector rig. The preliminary volume estimate is between 14 and 24 million barrels of recoverable oil equivalents.

– With Johan Castberg, we opened a new oil province in the Barents Sea one year ago. It is encouraging that we are now making new discoveries in the area. We plan to drill one to two exploration wells annually in this region going forward to increase the resource base and maintain plateau production for a longer period, says Grete Birgitte Haaland, area director for Exploration and Production North at Equinor.

The volume basis in Johan Castberg was originally estimated at 500–700 million barrels, and Equinor has an ambition to increase this by an additional 200–500 million barrels.

In June 2025, an oil discovery called “Drivis Tubåen” was made in the Castberg area, estimated at 13–20 million barrels in the Drivis structure.

Last week marked the start of construction for the development of Isflak, the first discovery to be tied into Johan Castberg. Aker Solutions in Sandnessjøen is building a well frame for two new wells that will be connected to existing subsea facilities.