Chinese oil producer CNOOC and state-owned Ghana National Petroleum Corp (GNPC) failed to buy US Kosmos Energy LLC's stake in Jubilee Oilfield in a joint bid, according to a foreign report giving no explanation for the setback.

CNOOC made a $5 billion joint bid with GNPC last month for Kosmos'23.5% stake in Jubilee Oilfield in the West African state, after an earlier bid by Exxon Mobil of more than $4 billion failed last year.

Jubilee Oilfield, seen as the largest offshore oilfield discovered in West Africa in the last decade, has an estimated proven reserves of 1.5 billion barrels of light crude.

GNPC holds a 13.75% stake in Jubilee. The oilfield will start output from December this year, making Ghana one of Africa's major oil producers.

China's business press carried the story above on Wednesday. China.org.cn has not checked the stories and does not vouch for their accuracy.