Equinor plans to tie its latest Barents Sea discovery into the Johan Castberg floating production facility.
On 18 March, Equinor announced it had found estimated recoverable resources of 14 million to 24 million BOE at its Polynya Tubåen prospect, which it plans to tie back to the floating production, storage, and offloading (FPSO) vessel serving the Johan Castberg field.
“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,” Grete Birgitte Haaland, Equinor’s area director for exploration and production north, said in a news release.
The volume basis in Johan Castberg was originally estimated at 500–700 million bbl. Equinor aims to increase this by an additional 200–500 million bbl. In June 2025, Equinor found an estimated 13 million to 20 million bbl of oil with the Drivis Tubåen prospect.
The COSL Prospector drilled well 7220/7-5 in the Polynya Tubåen prospect in 361-m water depth about 16 km southwest of the Johan Castberg discovery well, 7220/8-1, according to the Norwegian Offshore Directorate (NOD). Well 7220/7-5 is the 17th exploration well in production license 532, which was awarded in 2009 during the 20th Norwegian Continental Shelf licensing round. The first discovery in the field followed in 2011.
The Polynya Tubåen well was drilled to test for petroleum in Lower Jurassic reservoir rocks of the Tubåen formation.
According to the NOD, the well encountered a 26-m gas column and a 26-m oil column within 39 m of reservoir-quality rock, which ranged from good to very good. The total thickness of the Tubåen formation is 125 m. The gas/oil contact was encountered at 972 m below sea level, and the oil/water contact at 998 m below sea level. The well reached a vertical depth of 1,119 m below sea level and was terminated in the Upper Triassic Fruholmen formation.
The well was not formation-tested, but extensive volumes of data and samples were collected.
Equinor also said work started last week on the Isflak tieback to the Johan Castberg FPSO, which has been in production since March 2025 and reached peak production in June 2025. For Iskflak, Aker Solutions in Sandnessjøen has begun building a well frame for two new wells that will be connected to existing subsea facilities.
Equinor operates the Johan Castberg field with a 46.3% interest on behalf of partners Vår Energi, with 30%, and Petoro, with 23.7%.