Energy company Equinor has started production at the Trestakk subsea field on Haltenbanken in the Norwegian Sea.
Tied back to the Åsgard A floating production vessel, the field has estimated recoverable resources of 76 million barrels of oil.
The Åsgard A floating production vessel has been modified to receive production from Trestakk.
The company claimed that field production started on time, below budget, and without any serious incidents.
Equinor technology, projects and drilling executive vice-president Anders Opedal said: “Together with our partners ExxonMobil and Vår Energi we spent ample time on maturing Trestakk, and with proper assistance by our main supplier TechnipFMC we arrived at a good and profitable concept with development costs nearly halved before the investment decision was made.
“This proves that it is important and correct to spend sufficient time in the early phase of a project.”
The investment was estimated at Nkr5.5bn ($643m) when the authorities approved the project in 2017. However, Equinor said that the final costs are expected to be Nkr5bn ($585m) on field start-up.
Opedal added: “The project has managed to maintain its focus on cost efficiency after the investment decision was made, freeing up capital that we and our partners can use on other projects.”
The operator Equinor Energy has a 59.1% stake in Trestakk, ExxonMobil Exploration and Production Norway 33%, and Vår Energi 7.9%.
Trestakk field is 20km south of Åsgard field in depths of around 300m, while the reservoir is at depths of approximately 3,900m.
Trestakk field development covers a subsea template with four well slots and one satellite well. Three wells will be drilled for production and two for gas injection.
The operations life of Åsgard A was originally due to end this year. However, the Petroleum Safety Authority Norway and the Norwegian Petroleum Directorate have since approved an extension of the lifetime of the installation until 2031.
Trestakk will produce around 22,000bpd of oil, with peak production around 44,000bpd Trestakk field production is expected to last for 12 years.