China National Offshore Oil (CNOOC) has received the final approval from the Committee on Foreign Investment in the United States (CFIUS) to acquire Canada-based oil and gas company Nexen, for $15.1bn.

Nexen said in a statement that the deal is expected to close in the week of 25 February 2013, seven months after China’s major offshore oil and gas producer made its bid of $27.50 a share.

The company, however, did not specify whether CFIUS had imposed conditions on the approval.

The deal was supported by Canadian authorities, but required US approval as Nexen has operations in the country.

As part of the acquisition, CNOOC will gain rights to new offshore production in the North Sea, the Gulf of Mexico and off western Africa, in addition to producing assets in the Middle East and Canada, reported Reuters.

CNOOC will also gain control over Nexen’s Long Lake oil sands project in the province of Alberta, Canada, and billions of barrels of reserves in the world’s third-largest crude storehouse.

Bracewell & Guiliani senior counsel Joshua Zive was quoted by the Reuters as saying that CNOOC’s achievement in steering the CFIUS approval process "is likely to be viewed as a positive development".

"That, in the current climate, is a moment of significance," Zive added.