China National Offshore Oil Corporation Ltd (CNOOC Ltd) and Ghana National Petroleum Corp together outbid Exxon Mobil for oil assets in the west African nation of Ghana, reports said Wednesday.

The $5 billion offer topped the over $4 billion offer from Exxon Mobil for Kosmos Energy LLC assets - which include a 23.49 percent stake in the Jubilee oil field. Located some 12 km from the Ghanaian coastline, Jubilee oil field holds an estimated 1.8 billion barrels of crude. The deal has attracted global oil giants including Total, BP, Sinopec, Chevron and Sweden Petroleum Group.

Calls to CNOOC Ltd went unanswered Wednesday.

Dallas, Texas-based Kosmos' owns a 23.5 percent stake in Ghana's Jubilee field, and state-owned Ghana National Petroleum holds 13.8 percent.

"The recent series of overseas transactions for oil and gas reflects China's eagerness to obtain new energy (sources) to meet the country's surging economic demand," said Lin Boqiang, director, China Center for Energy Economics Research at Xiamen University.

Just two weeks ago, China National Offshore Oil Corp, parent of CNOOC Ltd, announced it would spend $1.08 billion in cash to acquire 33.3 percent of shale oil and gas projects in Texas.