BP is set to increase its investment in the North Sea amid the slump in oil and gas prices after agreeing a deal to double its stake in the giant Culzean field east of Aberdeen.

The company has agreed to buy a 16 per cent interest in the field from JX Nippon of Japan in a deal which will leave it with a 32 per cent holding in Culzean. This is one of the biggest North Sea fields found in the last 20 years.

The deal will result in BP’s share of the £3bn cost of developing Culzean rising by around £500m to £1bn.

The company has made the move after announcing plans in January to shed 600 jobs in the North Sea.

The head of the North Sea business, Mark Thomas, said then BP had to make the operation more competitive amid toughening market conditions.

Against that backdrop the deal with JX Nippon may raise eyebrows.

Oil and gas prices have risen from the lows they hit in January amid hopes that major producing countries would curb output.

However, experts have said prices will remain under pressure for some time.

The decision to increase investment in Culzean shows BP’s faith in a strategy that involves focusing investment on large new fields which it expects to be in production for years. These include Quad 204 and Clair Ridge West of Shetland.

Culzean is expected to come onstream in 2019 and to remain in production into the 2030s. BP noted the field is expected to produce enough gas to meet five per cent of total UK demand at peak production in 2020/21.

Such huge fields will be able to capitalise on the eventual upturn in the market that industry leaders expect to occur amid growing demand for energy and cuts in spending on projects globally.

New fields feature modern production technology which allows oil and gas firms to secure better profit margins than they do on the output from older fields.

Firms that operate fields have been putting pressure on the services businesses that help them to develop and run operations to squeeze costs out of the supply chain.

BP said cuts in the prices of services will mean its overall spending on North Sea projects increases by less than £500m following the Culzean deal.

The company will invest around $2bn (£1.4bn) in the North Sea this year.

It is thought the acquisition of the stake in Culzean will involve BP making a relatively modest payment to JX Nippon, which may be glad to reduce its share of the cost of developing the field.

The head of BP’s North Sea business Mark Thomas said: “BP has been focusing and refreshing its North Sea portfolio by bringing new fields into production, redeveloping and renewing existing producing facilities and divesting some of its more mature or less strategic assets.”

He added: “This is a challenging time for the industry and we must continue to work together to ensure that when developments like Culzean, or other projects such as BP’s Quad 204 and Clair Ridge, come online they can be run as efficiently as possible.”

Culzean was discovered in 2008, and was billed as the biggest North Sea gas find in a decade.

The field is estimated to contain up to 300 million barrels oil equivalent of gas condensate.

It is being developed by Denmark’s Maersk Oil, which made no comment about the deal.

JX Nippon acquired a big portfolio of North Sea interests from Italy’s Eni in 2012 when the company said it wanted to develop a big production business in the UK.

The company did not comment on the deal with BP.

BP has around 3,000 people working for it in the North Sea, including staff and contractors. The company will cut 600 posts over the next two years under the plans announced in January.

A further 400 people are working on fixed term contracts which will end when Quad 204 and Clair Ridge come onstream.