Johan Castberg hub expands: Equinor invests in 46 MMbbl Isflak development
Equinor, Vår Energi and Petoro will invest just over NOK 4 billion to develop the Isflak discovery— the first find to be tied back to the Johan Castberg field in Norway’s Barents Sea. The decision comes eight months after Johan Castberg came onstream and continues the operator’s strategy to build the field into a long-term production hub for the region.
The new subsea development, estimated to hold 46 MMbbl of recoverable oil, is expected to start up as early as Q4 2028. Equinor said the fast-track schedule is possible because the Isflak reservoir sits within the same license (PL 532) and is similar to existing Johan Castberg discoveries, enabling reuse of standardized equipment and well designs.
“Johan Castberg has been developed as a future hub in the area. Isflak is the first of several discoveries now being matured for additional volumes,” said Trond Bokn, Equinor’s SVP for project development. “This will have ripple effects for Norwegian suppliers.”
Johan Castberg, which began production in March, is currently delivering around 220,000 bpd. Estimated recoverable volumes for the hub stand between 450–650 MMbbl, but Equinor sees significant upside—potentially 250–550 MMbbl from new wells and satellite tiebacks. Six new improved oil recovery wells are already planned, and the partnership is evaluating how quickly this year’s Drivis Tubåen discovery could be brought online.
Equinor said the project reflects an evolving Norwegian continental shelf, where most future developments will be smaller finds rapidly tied back to existing infrastructure to reduce costs, emissions and extend field life.
The Isflak concept includes two wells in a new subsea template tied back via pipelines and umbilicals to existing Johan Castberg facilities. All infrastructure will remain within the current license area. Equinor has applied to the Ministry of Energy for confirmation of impact assessment obligations and an exemption from submitting a full plan for development and operation.
Pictured at top: The Johan Castberg production vessel was towed to the field in August 2024. Production started in June the following year. Photo: Olaf Nagelhus / Equinor
