BEIJING (

TheStreet

) --

Cnooc

(CEO) - Get Report

, the big Chinese state-owned oil company, is in talks to buy large stakes in some of the world's richest oil blocks in Nigeria, a report says.

Cnooc is trying to buy 6 billion barrels of oil, which is equivalent to one in every six barrels of the proven reserves in Nigeria, the

Financial Times

reports.

Cnooc's attempt to secure the blocks could put it in competition

Royal Dutch Shell

(RDS.A)

,

Chevron

(CVX) - Get Report

,

Total

(TOT) - Get Report

and

Exxon Mobil

(XOM) - Get Report

, which partly or wholly control and operate 23 blocks under discussion. Sixteen licenses are up for renewal, the newspaper reports.

The value of the Chinese offer wasn't disclosed in a letter from the office of Nigeria's president to a Cnooc representative that was obtained by the

Financial Times

. Some details suggest a figure of about $30 billion, while some oil sector executives said the total on the table was $50 billion, the

Financial Times

adds.

A spokesman for Umaru Yar'Adua, Nigeria's president, told the newspaper that negotiations were ongoing not only with Cnooc but "also with all other stakeholders in the industry. The federal government has not taken any final position on the issue."

-- Reported by Joseph Woelfel in New York

.

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