Norway’s Equinor his made a major new discovery close to its Johan Castberg field under development in the country’s Barents Sea waters.

Preliminary calculations indicate the Snofonn Nord find holds between 37 million and 50 million barrels of recoverable oil — valuable additional volumes for Johan Castberg, which is expected to have a very short plateau production term of two to three years without additional tied-in discoveries.

Equinor has already discovered additional volumes close to Castberg and the Snofonn Nord find was made a year after the smaller Isflak discovery in the same area.

The company’s senior vice president for exploration and production north, Kristin Westvik, said: “Snofonn Nord is an exciting discovery in the vicinity of the Johan Castberg development and can add valuable volumes to the installation in the future.”

The well was drilled by the semi-submersible rig Transocean Enabler, which will move 800 metres west to drill a new exploration well.

Johan Castberg holds estimated recoverable reserves of 450 million to 650 million barrels of oil equivalent.

The field is to be developed via a floating production, storage and offloading vessel designed to produce 190 000 barrels per day, with output due to begin in 2024.

The Johan Castberg FPSO arrived in Norway last month, with the turret and process modules to be installed at Aker Solutions’ Stord facility.

Johan Castberg lies about 100 kilometres north of the Snohvit field and 240 kilometres off the Norwegian mainland.

Equinor holds a 50% operating stake in the Johan Castberg licence, with Vaar Energi holding 30% and Petoro 20%.