China's Sinopec Group has agreed to buy Marathon Oil Corp's (MRO.N) Angolan offshore oil and gas field for $1.52 billion, Asia's largest refiner producer said.

Sonangal Sinopec International Ltd, the group's subsidiary, will acquire Houston-based Marathon's 10 percent stake on the Angolan field called Block 31, it said in a statement late on Friday.

China's oil majors has been on an aggressive hunt for overseas assets to bulk up their energy reserves to meet future demand from the world's second-largest economy.

CNPC agreed in March to buy a $4.2-billion stake in a Mozambique offshore natural gas field and on Friday agreed to buy a 20 percent stake in Novatek's (NVTK.MM) $20-billion Yamal-LNG project in northwest Siberia.

The Angolan Block 31 field, operated by BP (BP.L), has estimated proved and probable reserves of 533 million barrels, Sinopec said, adding that it would hold a stake of 15 percent in the block when the transaction was completed.

The $1.52 billion due to be paid by Sinopec is part of a $3-billion asset disposal target set by Marathon in 2011 to shore up its balance sheet to fund further exploration and development projects. The deal is subject to approval by the Chinese and Angolan governments.