Norwegian oil giant Statoil is to sell off its stakes in the Schiehallion and Rosebank North Sea fields as part of a deal worth at least $2.65billion.

The company, which is also reducing its stake in the Gullfaks and Gudrun Norwegian North Sea fields, could make a further $500million from the sale depending on 2013 prices.

Austrian player OMV will take over Statoil’s 30% stake in the Rosebank field, and 5.88% share of the Schiehallion operation, as the Norwegian firm exits the two areas entirely.

Statoil will remain operator of Gullfaks and Gudrun, but sees its stake in both fields cut to 51% from 70% and 75% respectively, with OMV agreeing a cooperation deal for exploration across the UK, Norway and the Faroe Islands.

“Statoil is pleased to strengthen the partnership with OMV on the Norwegian Continental shelf,” said Statoil chief executive Helge Lund.

“OMV is already a valued partner in Edvard Grieg and Aasta Hansteen, and this agreement enables our companies to develop the cooperation further.”

The deal will give Statoil more revenue to develop the massive Johan Sverdrup field in the Norwegian North Sea, which analyists predict could hold up to 3.3billion barrels of oil, along with further interests in Norway and Brazil.

The company said disposing of its Shiehallion and Rosebank stakes would allow it to focus on the core parts of its UK portfolio, including the large Mariner development.

“Through this transaction, Statoil captures value created through asset development and unlocks capital for investment in high return projects in core areas,” said Lund.

“This includes our recent discoveries on the Norwegian continental shelf.

“We continue to deliver on our strategy to create value through active portfolio management and to further increase our financial flexibility.”

OMV said the deal, which would give them access to around 320million barrels of oil equivalent, was funded from recent selloffs and savings in the company’s downstream business.

The deal gives OMV a 50% stake in the giant Rosebank field, operated by Chevron, for which a final investment decision is due next year. Production, estimated at around 50,000boed, is set to begin on the field by 2018.

The purchases will boost OMV’s daily production by around 40,000 barrels as they close in on a target increase of 58,000 boed by 2016.

OMV’s stake in Schiehallion, the UK’s second largest oil field, now increased to 11.76% ahead of production resuming after a major redevelopment in 2016.

“The transaction will provide a huge boost to OMV’s strategy and will be a key factor in achieving our 2016 targets,” said OMV chief executive Gerhard Roiss.

“It confirms OMV’s clear focus towards increasing the significance of its E&P activities. We are acquiring significant positions in developments lying at the heart of our North Sea growth region.

“Furthermore, the agreement to partner with Statoil on exploiting a number of exploration activities in the North Sea and West of Shetland area as well as the agreement to jointly work on enhanced oil recovery research adds both to our know how as well as the size of our exploitable asset base in the long term.”

Last month Statoil completed a $1.4billion asset swap with German oil group Wintershall for a host of Norwegian North Sea assets.