CALGARY, Feb. 25, 2013 /PRNewswire/ – Nexen Inc. (“Nexen” or the “Company”,
TSX, NYSE: NXY) announced today that CNOOC Limited has completed its
acquisition of the Company. Pursuant to the plan of arrangement (the
“Arrangement”) holders of Nexen common shares will receive cash
proceeds of US $27.50, without interest, and holders of Nexen preferred
shares will receive cash proceeds of CAD $26.00, plus accrued and
unpaid dividends up to, but excluding, the closing date of the
Arrangement, without interest.

Kevin Reinhart will continue as CEO of Nexen and will maintain
responsibility for all of Nexen’s operations. The Company’s Calgary
headquarters will continue to be responsible for managing all of
Nexen’s existing assets as well as CNOOC Limited’s North and Central
American assets.

Nexen’s common and preferred shares are expected to be delisted from the
Toronto Stock Exchange (the “TSX”) in a few trading days. Nexen’s
common shares are expected to cease being traded on the NYSE prior to
the market opening on February 26, 2013, and will subsequently be
delisted.

Nexen Establishes New Board of Directors

Following the completion of the transaction, Nexen established a new
Board of Directors comprised of representatives of CNOOC Limited and
Nexen, as well as independent directors. Mr. Li Fanrong has been
appointed Chair of the Board of Nexen. Mr. Li Fanrong is the CEO of
CNOOC Limited, and has more than 28 years of experience in the oil and
gas industry including in the North Sea. The other directors serving on
the Nexen Board are Mr. Fang Zhi, Vice President CNOOC Limited, Mr.
Kevin Reinhart, Mr. Barry Jackson, Mr. Thomas O’Neill and Mr. William
Berry.

About Nexen

Nexen Inc. is a wholly-owned subsidiary of CNOOC Limited. Nexen is
focused on three growth strategies: oil sands and shale gas in western
Canada and conventional exploration and development primarily in the
North Sea, offshore West Africa and deepwater Gulf of Mexico.

Forward-Looking Statements

Certain statements in this Release constitute “forward-looking
statements” (within the meaning of the United States Private Securities
Litigation Reform Act of 1995, as amended) or “forward-looking
information” (within the meaning of applicable Canadian securities
legislation). Such statements or information (together “forward-looking
statements”) are generally identifiable by the forward-looking
terminology used such as “will”, “intends”, “expect”, “should” or other
similar words. More particularly and without limitation, this Release
contains forward-looking statements and information concerning the
delisting of the common shares and the preferred shares from the TSX
and the NYSE, as applicable.

In respect of the forward-looking statements and information concerning
the delisting of the common shares and the preferred shares from the
TSX and NYSE, as applicable, Nexen has provided such in reliance on
certain assumptions that it believes are reasonable at this time,
including assumptions as to the time necessary, and the ability of
Nexen to complete the delisting of the common shares and the preferred
shares from the TSX and the NYSE, as applicable. The date of delisting
may be delayed or changed for a number of reasons. Accordingly, readers
should not place undue reliance on the forward-looking statements and
information contained in this Release concerning these times.

Nexen undertakes no obligation to update publicly or revise any
forward-looking statements or information, whether as a result of new
information, future events or otherwise, unless so required by
applicable securities laws.

SOURCE Nexen Inc.