UNITED STATES
                       SECURITIES AND EXCHANGE COMMISSION

                             WASHINGTON, D.C. 20549


                                 CURRENT REPORT

                     PURSUANT TO SECTION 13 OR 15(D) OF THE
                         SECURITIES EXCHANGE ACT OF 1934

         Date of Report (date of earliest event reported): May 12, 2005


                                   NEXEN INC.
             (Exact name of registrant as specified in its charter)


                                     CANADA
- --------------------------------------------------------------------------------
                 (State or other jurisdiction of incorporation)


                  1-6702                                 98-6000202
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         (Commission File Number)             (IRS Employer Identification No.)


                              801 - 7TH AVENUE S.W.
                        CALGARY, ALBERTA, CANADA T2P 3P7
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                    (Address of principal executive offices)


       Registrant's telephone number, including area code: (403) 699-4000
- --------------------------------------------------------------------------------
                                 NOT APPLICABLE

          (Former name or former address, if changed since last report)

     Check the appropriate box below if the Form 8-K filing is intended to
simultaneously satisfy the filing obligation of the registrant under any of the
following provisions (SEE General Instruction A.2. below):

     [_] Written communications pursuant to Rule 425 under the Securities Act
(17 CFR 230.425)

     [_] Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17
CFR 240.14a-12)

     [_] Pre-commencement communications pursuant to Rule 14d-2(b) under the
Exchange Act (17 CFR 240.14d-2(b))

     [_] Pre-commencement communications pursuant to Rule 13e-4(c) under the
Exchange Act (17 CFR 240.13e-4(c))




ITEM 9.01.   FINANCIAL STATEMENTS AND EXHIBITS.

(b)          Pro Forma Financial Information.

             Nexen Inc. (the "Company") hereby furnishes pro forma financial
information for the year ended December 31, 2004, giving effect to the
acquisition of EnCana (U.K.) Limited.

(c)          Exhibits:

             EXHIBIT     DESCRIPTION
             -------     -----------
             4.8         The Company's pro forma consolidated
                         statement of income (unaudited) for the year
                         ended December 31, 2004, giving effect to the
                         acquisition of EnCana (U.K.) Limited



FORWARD-LOOKING STATEMENTS

             Certain statements in this report constitute "forward-looking
statements" within the meaning of the United States Private Securities
Litigation Reform Act of 1995, Section 21E of the United States Securities
Exchange Act of 1934, as amended, and Section 27A of the United States
Securities Act of 1933, as amended. Such statements are generally identifiable
by the terminology used such as "intend", "plan", "expect", "estimate",
"budget", "outlook" or other similar words.

             The forward-looking statements are subject to known and unknown
risks and uncertainties and other factors which may cause actual results, levels
of activity and achievements to differ materially from those expressed or
implied by such statements. Such factors include, among others: market prices
for oil and gas and chemicals products; the ability to explore, develop, produce
and transport crude oil and natural gas to markets; the results of exploration
and development drilling and related activities; foreign-currency exchange
rates; economic conditions in the countries and regions where Nexen carries on
business; actions by governmental authorities including increases in taxes,
changes in environmental and other laws and regulations; renegotiations of
contracts; and political uncertainty, including actions by insurgent or other
armed groups or other conflict. The impact of any one factor on a particular
forward-looking statement is not determinable with certainty as such factors are
interdependent upon other factors, and management's course of action would
depend on its assessment of the future considering all information then
available. Any statements as to possible commerciality, development plans,
capacity expansions, drilling of new wells, ultimate recoverability of reserves,
future production rates, cash flows and changes in any of the foregoing are
forward-looking statements.

             Although we believe that the expectations conveyed by the
forward-looking statements are reasonable based on information available to us
on the date such forward-looking statements were made, no assurances can be
given as to future results, levels of activity and achievements. Readers should
also refer to our Annual Report on Form 10-K for a discussion of the risk
factors.





                                    SIGNATURE

         Pursuant to the requirements of the Securities Exchange Act of 1934,
the registrant has duly caused this report on Form 8-K to be signed on its
behalf by the undersigned, thereunto duly authorized.

Dated:  May 12, 2005

                                          NEXEN INC.


                                          By: /s/ Sylvia L. Groves
                                              ---------------------------------
                                          Name:   Sylvia L. Groves
                                          Title:  Assistant Secretary




EXHIBIT INDEX


EXHIBIT      DESCRIPTION
- -------      -----------
4.8          The Company's pro forma consolidated statement of income
             (unaudited) for the year ended December 31, 2004, giving
             effect to the acquisition of EnCana (U.K.) Limited