Sinopec Group, the country's top oil refiner, announced that it has signed a deal with U.S. oil giant Marathon Oil Corp. to buy its oil and gas field in Angola for $1.52 billion.

According to the deal, Sinopec Group will purchase Marathon's 10-percent stake on the Angolan Block 31 field through its subsidiary Sonangal Sinopec International Ltd.

The Angolan Block 31 field, operated by British Petroleum (BP), has estimated proven and probable oil reserves of 533 million barrels, Sinopec said.

Together with the 5-percent stake in Block 31 Sinopec purchased from French oil giant Total in 2011, Sinopec's stake in the block will reach 15 percent upon the completion of the Marathon deal.

The deal is subject to approval by the Chinese and Angolan governments.