$400 million going into subsea tie-back to huge Barents Sea oil project

December 11, 2025, by Melisa Cavcic

Three Norwegian oil and gas players – Equinor, Vår Energi, and Petoro – have set their caps on augmenting the production from a giant oil field that came online eight months ago in the Barents Sea by adding what will become the first subsea tie-back to the project, said to be the newest oil production hub on the Norwegian Continental Shelf (NCS).

While disclosing plans to invest just over NOK 4 billion (around $400 million) in the first discovery, known as Isflak, to be tied back to the Johan Castberg field in the Barents Sea, Equinor explained that the decision was made eight months after the field came on stream. The recoverable oil in the new subsea development is estimated at 46 million barrels, and start-up is planned as early as the fourth quarter of 2028.

Trond Bokn, Equinor’s Senior Vice President for Project Development, commented: “A rapid development is possible because we can copy standardised solutions from Johan Castberg. The reservoir is in the same licence and is similar to the discoveries we have developed previously, which means that we can copy equipment and well solutions.

“Johan Castberg has been developed as a future hub in the area. Isflak from 2021 is the first of several discoveries that are now being matured as additional volumes. This will have ripple effects for Norwegian suppliers.”

As the NCS changes, many of the developments in the future are perceived to be smaller discoveries that can quickly be tied back to existing infrastructure and larger fields. As a result, costs and environmental footprints are expected to be reduced, value creation and jobs extended, and Norway’s role as a reliable and long-term energy supplier maintained.

The development solution for the Isflak discovery comprises two wells in a new subsea template, tied back to existing subsea facilities via pipelines and umbilicals. All new infrastructure is located within the current Johan Castberg license.

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Equinor has applied to the Ministry of Energy for confirmation that it has fulfilled its impact assessment obligation and is exempt from the requirement for a plan for development and operation (PDO). Global combustion emissions have been assessed in line with the new practice.

According to Equinor, Johan Castberg is the newest oil production hub on the NCS, which was put on stream in March 2025 and is now producing 220,000 barrels per day. New projects and new recoverable wells are anticipated to extend plateau production from the field, which currently has estimated recoverable volumes of between 450 and 650 million barrels.

Grete Birgitte Haaland, Senior Vice President for Exploration & Production North, remarked: “We see opportunities to add 250-550 million new recoverable barrels that can be developed and produced over Johan Castberg. The partnership is already planning six new wells for improved oil recovery, and we will explore more in the area.”

Earlier this year, a discovery was made in a new segment of the Johan Castberg licence, Drivis Tubåen, as an exploratory extension from a production well. The partnership will now, in consultation with the authorities, assess how it can be quickly put into production mode.

Haaland added: “Equinor’s ambition is to maintain the production level on the NCS from 2020 until 2035, although production from the current fields will decline. A significant part will come from new wells and projects.

“We are planning about 75 subsea developments in the next few years, and this project is a good example of how this can be done efficiently working closely with licence partners and authorities.”

The Johan Castberg field entails the Skrugard, Havis, and Drivis discoveries made in the period from 2011 to 2014. The field is situated 240 kilometers from Hammerfest and 100 kilometers north of the Snøhvit field in the Barents Sea. The partners in the license are Equinor (operator, 46.3%), Vår Energi (30%), and Petoro (23.7%).

The development solution includes a floating production, storage, and offloading (FPSO) tied back to an extensive subsea field with 30 wells divided on ten subsea templates and two satellite structures. The Isflak discovery, which is now being developed in the same license, PL 532, was made in 2021, during the Johan Castberg development process.

Torger Rød, Vår Energi’s COO, highlighted: “The projects underline the Barents Sea’s potential and marks an important step in Vår Energi’s plan to sustain production of 350 to 400 thousand barrels of oil equivalent per day (kboepd) towards 2030 and beyond.

“The development leverages existing infrastructure to secure Johan Castberg plateau production for years to come, strengthening our position in the region and reaffirming our long-term commitment to value creation.”

Given the multiple discoveries and prospects that can be developed to maximize production over time, the plan is to drill one to two exploration targets each year, with four identified prospects already lined up for 2026 and 2027.

The Johan Castberg area is described as holding a substantial resource potential, and the license is targeting to unlock more than one billion barrels over the asset’s lifetime, with opportunities to sustain plateau production towards 2030.