North Sea producer EnQuest said it was playing to its strength of getting more out of mature basins by grabbing a stake in an oil field from BP.

BP under the terms of the deal keeps a majority stake in the Magnus oil field in the North Sea, but sheds a quarter of its stake to Enquest in an acquisition priced at $85 million. Amjad Bseisu, the CEO at EnQuest, said moving in alongside BP creates an opportunity to yield more from regional waters.

"This transaction capitalizes on EnQuest's strengths in realizing value from the management of maturing oil fields," he said in a statement.

Magnus, located in the northern British waters of the North Sea, produced on average 17,000 barrels of oil equivalent per day last year. BP recently completed an overhaul of its operations in the region with the aim of extending their life to at least 2035.

Regional waters last year attracted the attention of other players with an eye on North Sea assets. Norwegian energy company Statoil opened an office in Aberdeen with an eye on building a stronger footprint in the regional waters.

Data published by the Scottish government said the North Sea remains the largest oil producer and second largest natural gas producer in Europe.

Bob Dudley, the CEO at BP, said EnQuest has a legacy of extending the life of maturing basins in the North Sea and is therefore a natural partner at Magnus.

"We believe this will enable them to prolong the life of the assets, benefiting the region and creating additional value for both EnQuest and BP shareholders," he said.

EnQuest under the agreement has the option to buy the rest of BP's stake in Magnus by January 2019 for $300 million. The company in November delivered its first batch of oil from a North Sea field that could hold more than 10 million barrels of oil. The Scolty/Crathes complex about 100 miles north of Aberdeen, Scotland, came to production ahead of schedule and under budget.