BEIJING, Nov. 5, 2009 (Xinhua News Agency) -- CNOOC Ltd. (NYSE:CEO) (CEO.NYSE; 0883.HK) has acquired a stake in four Gulf of Mexico oilfields from Norwegian state oil firm Stateoil, revealed the third quarter financial report of Stateoil.

In its third quarter report, Stateoil said that it has sold some equity in its four oilfields - Tucker, Logan, Cobra, and Krakatoa - in the Gulf of Mexico to CNOOC Ltd. The latter now holds a 20 percent share in exploring Tucker and 10 percent shares in each of the other three blocks.

It is for the first time that a Chinese oil firm holds equity in American oil assets. The last time CNOOC attempted to acquire US UNOCAL Corporation in 2005, it confronted opposition in America, which has long dampened the enthusiasm of Chinese oil firms to invest in American oil and gas assets.

The Gulf of Mexico holds great potential for oil and gas production and its current output accounts for one-fourth of the US total.

It is forecasted that the annual production of the Gulf of Mexico would reach 1.6 million barrels before 2011 and may climb to 1.9 million barrels before 2013.