Sinopec Group, Asia's largest refiner, announced it has agreed to buy 10 percent of Marathon Oil Corp's Angolan offshore oil and gas field for $1.52 billion.

Sonangal Sinopec International Ltd, a group subsidiary, will acquire 10 percent of the shares in Houston-based Marathon’s field, Block 31, the State-owned oil company said.

Marathon Oil Co is an American independent oil company and owns 10 percent stake of Block 31 and 10 percent stake of the Block 32. Block 31 is operated by British oil giant BP Plc and has estimated proved and probable reserves of 533 million barrels, according to Sinopec.

Sinopec will own up to 15 percent of Block 31 under the deal.

The company said the deal will provide additional production of about 14,600 barrels a day and further help the group gain more overseas exploration experience.