China Petrochemical’s (Sinopec) subsidiary Sonangal Sinopec International has agreed to acquire a 10% stake in the US-based Marathon Oil’s offshore oil and gas field Block 31 in Angola, for $1.52bn.

In 2011, Sinopec acquired a 5% stake in the block for $983m from French oil and gas group Total.

The latest acquisition, which will increase Sinopec’s stake in Block 31 to 15%, as well as increase its production to 14,600 barrels of oil per day.

Block 31, currently operated by BP, is estimated to have proved and probable reserves of 533 million barrels.

The deal, which is subject to approval from the governments of China and Angola, is part of a $3bn asset disposal target of Marathon Oil set out in 2011 to improve its balance sheet and advance exploration and development projects.

In September 2009, Angola state-owned company Sonangol announced that it will buy Marathon Oil’s 20% stake in Angola’s Block 32, valued at $1.3bn.