Norway-based Equinor and its partners have started production from the offshore Aasta Hansteen gasfield, 300km west of Sandnessjøen.
Equinor has also started supplying gas to the market through the 482km long Polarled pipeline, which will transport it to Nyhamna terminal for further export to the UK.
Three subsea templates are used to produce the gas.
Equinor has invested around Nkr37.5bn ($336m) to develop the Aasta Hansteen field in the Norwegian Sea.
Aasta Hansteen field development concept comprises a floating platform with a vertical spar platform, which is 339m tall and weighs 70,000t.
Equinor Technology, Projects and Drilling executive vice-president Anders Opedal said: “Located in 1,300m of water, this is the deepest field development on the Norwegian continental shelf (NCS), the largest spar platform in the world, and a first on the NCS.
“The field now coming on stream is unique.”
In addition, Aasta Hansteen, along with the upcoming Snefrid North field, is expected to produce 55.6 billion standard cubic metres of gas and 600,000m³ of condensate.
Snefrid North is currently under development and scheduled to come on-stream next year.
Equinor Norway development and production executive vice-president Arne Sigve Nylund said: “The production from the Aasta Hansteen field will help secure long-term Norwegian gas export.
“With the infrastructure installed it will also be more attractive to explore around the platform and along the pipeline. This enables us to secure activity for many decades, in line with our ambitions for the NCS.”
The substructure and topside structure of Aasta Hansteen were manufactured in South Korea, while certain topside equipment packages and the subsea equipment used in the field were produced in Norway.
Equinor will operate the filed from Harstad and deliver base services from Sandnessjøen, Norway. Helicopter trips to the field will be provided from Brønnøysund.