Maersk Oil North Sea UK is acquiring a 25% interest in a block containing the Bagpuss oil prospect from Canada's North Sea Energy in return for funding an exploration well and a share of other costs.
The companies expect drilling will start next year.
Coming six months after Maersk won Government approval for the £150 million Balloch oil development in the UK North Sea, the farm-in deal reflects the company's strong interest in the area. The firm is owned by AP Moller-Maersk.
The managing director of Maersk Oil & Gas UK, Martin Rune Pedersen, said: "Maersk Oil firmly believes in the productive future of the North Sea and the opportunities that it offers. As a business, we are committed to growing our operations in the UK North Sea and are actively investing in increasing our footprint both on and offshore in Aberdeen."
In February, Mr Pedersen said the Balloch development 140 miles north east of Aberdeen was one of a number of UK projects Maersk is fully committed to bringing onstream in the coming years.
AP Moller-Maersk, has built a big position in the UK, helped by the £1.65bn acquisition of the bulk of Kerr-McGee's North Sea interests in 2005. The company expanded the portfolio in March when it acquired a 30% stake in the Isabella prospect in a farm-in deal with Valiant Petroleum, now owned by Ithaca Energy.
Maersk Oil UK will carry 100% of North Sea Energy's costs to drill the initial Bagpuss exploration well, plus 50% of the Canadian firm's costs on an appraisal well should one be drilled. Its contribution to the cost of both wells will be capped at an undisclosed level.
Maersk Oil will acquire a 25% working interest in blocks 13/24c and 13/25. North Sea Energy will retain a 15% working interest.
Toronto-based North Sea Energy says it is focused on the UK. It has interests in nine North Sea blocks.