BP acquired the interests in the fields - Magnolia, Merganser, Nansen and Zia - from Devon Energy earlier in 2010 as part of a wider acquisition of assets in the Gulf of Mexico, Brazil and Azerbaijan.
Andy Hopwood, BP executive vice president, Strategy and Integration, said: "When BP acquired Devon's Gulf of Mexico assets it was clear that these four fields did not fit well with the rest of our business in the region. We therefore decided they would be of more value to another company than to BP."
Marubeni will pay BP $650 million in cash for the interests, subject to customary post-closing adjustments. Dependent upon regulatory approval, the parties anticipate completing the deal in early 2011.
The assets included in the agreement comprise:
* a 25 per cent interest in the ConocoPhillips-operated Magnolia oil and gas field in the Garden Banks area of the Central Gulf;
* a 50 per cent interest in the Anadarko Petroleum-operated Merganser gas field in the Atwater Valley area of the Central Gulf;
* a 50 per cent interest in the Anadarko Petroleum-operated Nansen oil and gas field in the Western Gulf; and,
* a 65 per cent operating interest in the Zia oil and gas field in the Mississippi Canyon area of the Central Gulf.
BP's net production from these fields is approximately 15,000 barrels of oil equivalent a day (boed).
BP acquired a range of deepwater Gulf of Mexico assets from Devon Energy as part of a deal announced in March 2010. The agreement announced today does not affect BP's other interests in the Gulf of Mexico where it is both the largest producer of oil and gas - with current net production totalling approximately 400,000 boed - and the largest holder of leases.