As filed with the Securities and Exchange Commission on
                                                           September 24, 2004.
==============================================================================
                                                 Registration No: 333-________


                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549

                                   FORM S-8
            REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933


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


            CANADA                                        98-6000202
(State or other jurisdiction of                (IRS Employer Identification No.)
incorporation or organization)

                             ____________________

                             801 - 7th Avenue S.W.
                       Calgary, Alberta, Canada T2P 3P7

              (Address, including zip code, and telephone number,
       including area code, of registrant's principal executive offices)


                              Tandem Option Plan
                           (Full title of the plan)

                          Nexen Petroleum U.S.A. Inc.
                               12790 Merit Drive
                                    Suite 800
                              Dallas, Texas 75251
                    (Name and address of agent for service)


                                (972) 450-4600
         (Telephone number, including area code, of agent for service)

                             ____________________

<TABLE>
<CAPTION>
                                  COPIES TO:
<S>                                                               <C>
               John B. McWilliams                                               Edwin S. Maynard
Senior Vice President, General Counsel and Secretary                               Andrew J. Foley
                   Nexen Inc.                                     Paul, Weiss, Rifkind, Wharton & Garrison LLP
            801 - 7th Avenue S.W.                                        1285 Avenue of the Americas
     Calgary, Alberta, Canada T2P 3P7                                  New York, New York 10019-6064

<CAPTION>
                        CALCULATION OF REGISTRATION FEE
===============================================================================================================================
                                                              Proposed Maximum     Proposed Maximum
              Title of                    Amount to be         Offering Price     Aggregate Offering          Amount of
    Securities to be Registered         Registered (1)(2)       Per Share (3)            Price            Registration Fee
-------------------------------------------------------------------------------------------------------------------------------
<S>                                     <C>                   <C>                 <C>                     <C>
Common Shares, no par value             2,750,000 shares           $38.90            $106,975,000              $13,554
-------------------------------------------------------------------------------------------------------------------------------
</TABLE>

1)    This Registration Statement also applies to rights under the Registrant's
      Shareholder Rights Plan Agreement, which are attached to and tradable only
      with the common shares registered hereby. No registration fees are
      required for such rights as they will be issued for no additional
      consideration.

(2)   This Registration Statement shall, in accordance with Rule 416 under the
      Securities Act of 1933, as amended, be deemed to cover such additional
      shares as may be issued to prevent dilution resulting from stock splits,
      stock dividends or similar transactions.

(3)   Calculated in accordance with Rule 457(c) and (h)(1) under the Securities
      Act, as amended, and equal to the average of the high and low prices
      reported on the New York Stock Exchange on September 20, 2004, a date
      within five business days of the filing of this Registration Statement.

<PAGE>


                               EXPLANATORY NOTE

                  We are filing this registration statement for the purpose of
registering, in accordance with General Instruction E of Form S-8, an
additional 2,750,000 Common Shares, no par value, to be issued under the
Registrant's Tandem Option Plan, formerly known as the Amended and Restated
Stock Option Plan. We incorporate by reference into this registration
statement on Form S-8 our previously filed registration statement on Form S-8,
as amended (File No. 333-13574, filed on May 31, 2001 and amended on September
12, 2003) in its entirety, including the exhibits to it.



                                    PART II

              INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 6.  Indemnification of Directors and Officers

                  Section 124 of the Canada Business Corporations Act provides
as follows:

124.     (1)      Indemnification. A corporation may indemnify a director or
                  officer of the corporation, a former director or officer of
                  the corporation or another individual who acts or acted at the
                  corporation's request as a director or officer, or an
                  individual acting in a similar capacity, of another entity,
                  against all costs, charges and expenses, including an amount
                  paid to settle an action or satisfy a judgment, reasonably
                  incurred by the individual in respect of any civil, criminal,
                  administrative, investigative or other proceeding in which the
                  individual is involved because of that association with the
                  corporation or other entity.

         (2)      Advance of Costs. A corporation may advance moneys to a
                  director, officer or other individual for the costs, charges
                  and expenses of a proceeding referred to in subsection (1).
                  The individual shall repay the moneys if the individual does
                  not fulfil the conditions of subsection (3).

         (3)      Limitation. A corporation may not indemnify an individual
                  under subsection (1) unless the individual

                  (a)      acted honestly and in good faith with a view to the
                           best interests of the corporation, or, as the case
                           may be, to the best interests of the other entity
                           for which the individual acted as director or
                           officer or in a similar capacity at the
                           corporation's request; and

                  (b)      in the case of a criminal or administrative action
                           or proceeding that is enforced by a monetary
                           penalty, the individual had reasonable grounds for
                           believing that the individual's conduct was lawful.

         (4)      Indemnification in derivative actions. A corporation may with
                  the approval of a court, indemnify an individual referred to
                  in subsection (1), or advance moneys under subsection (2), in
                  respect of an action by or on behalf of the corporation or
                  other entity to procure a judgment in its favour, to which the
                  individual is made a party because of the individual's
                  association with the corporation or other entity as described
                  in subsection (1) against all costs, charges and expenses
                  reasonably incurred by the individual in

<PAGE>


                  connection with such action, if the individual fulfills the
                  conditions set out in subsection (3).

         (5)      Right to indemnity. Despite subsection (1), an individual
                  referred to in that subsection is entitled to indemnity from
                  the corporation in respect of all costs, charges and
                  expenses reasonably incurred by the individual in connection
                  with the defence of any civil, criminal, administrative,
                  investigative or other proceeding to which the individual is
                  subject because of the individual's association with the
                  corporation or other entity as described in subsection (1),
                  if the individual seeking indemnity

                  (a)      was not judged by the court or other competent
                           authority to have committed any fault or omitted to
                           do anything that the individual ought to have done;
                           and

                  (b)      fulfills the conditions set out in subsection (3).

         (6)      Insurance. A corporation may purchase and maintain insurance
                  for the benefit of an individual referred to in subsection
                  (1) against any liability incurred by the individual

                  (a)      in the individual's capacity as a director or
                           officer of the corporation; or

                  (b)      in the individual's capacity as a director or
                           officer, or similar capacity, of another entity, if
                           the individual acts or acted in that capacity at
                           the corporation's request.

         (7)      Application to court. A corporation, an individual or an
                  entity referred to in subsection (1) may apply to a court
                  for an order approving an indemnity under this section and
                  the court may so order and make any further order that it
                  sees fit.

         (8)      Notice to Director. An applicant under subsection (7) shall
                  give the Director notice of the application and the Director
                  is entitled to appear and be heard in person or by counsel.

         (9)      Other notice. On an application under subsection (7) the
                  court may order notice to be given to any interested person
                  and the person is entitled to appear and be heard in person
                  or by counsel.

                  Section 7 of the By-laws of the Registrant contains the
following provisions with respect to indemnification of the Registrant's
directors and officers and with respect to certain insurance maintained by the
Registrant with respect to its indemnification obligations:

7.01     LIMITATION OF LIABILITY.

         Every director and officer of the Corporation shall act honestly and
         in good faith with a view to the best interests of the Corporation
         and shall exercise the care, diligence and skill that a reasonably
         prudent person would exercise in comparable circumstances, including
         reliance in good faith on:

                  (a)      financial statements of the Corporation represented
                           to the director by an officer of the Corporation or
                           in a written report of the auditor of the
                           Corporation fairly to reflect the financial
                           condition of the Corporation; or
                  (b)      a report of a person whose profession lends
                           credibility to a statement made by the professional
                           person.

<PAGE>


         Subject to the above provisions, no director or officer is liable for
         the acts, receipts, neglects or defaults of any other director,
         officer or employee, or for joining in any receipt or other act for
         conformity, or for any loss, damage or expense happening to the
         Corporation through the insufficiency or deficiency of title to any
         property acquired for or on behalf of the Corporation, or for the
         insufficiency or deficiency of any security in or upon which any of
         the moneys of the Corporation are invested, or for any loss or damage
         arising from the bankruptcy, insolvency or tortious acts of any
         person with whom any of the moneys, securities or effects of the
         Corporation are deposited, or for any loss occasioned by any error of
         judgement or oversight on the part of the director or officer, or for
         any other loss, damage or misfortune which happens in the execution
         of the duties of the office of the director or officer; provided that
         nothing in this section relieves any director or officer from the
         duty to act in accordance with the Act or from liability for any
         breach thereof.

7.02     INDEMNITY.

         Subject to the provisions of the Act, the Corporation shall indemnify
         a director or officer, a former director or officer, or another
         individual who acts or acted at the Corporation's request as a
         director or officer, or an individual acting in a similar capacity of
         another entity, against all costs, charges and expenses, including an
         amount paid to settle an action or satisfy a judgement, reasonably
         incurred by the individual in respect of any civil, criminal,
         administrative or investigative action or other proceeding in which
         the individual is involved because of that association with the
         Corporation or other entity if, exercising the care, diligence and
         skill that a reasonably prudent person would exercise in comparable
         circumstances:

                                    (a) the individual acted honestly and in
                  good faith with a view to the best interests of the
                  Corporation or, as the case may be, to the best interests of
                  the other entity for which the individual acted as director
                  or officer or in a similar capacity at the Corporation's
                  request; and

                                    (b) in the case of a criminal or
                  administrative action or proceeding that is enforced by a
                  monetary penalty, the individual had reasonable grounds for
                  believing that the individual's conduct was lawful.

         The Corporation shall also indemnify any of the other persons set out
         above in any other circumstances which the Act or law permits or
         requires. Nothing in this by-law limits the right of any person
         entitled to indemnity to claim indemnity apart from the provisions of
         this by-law to the extent permitted by the Act or law.

7.03     ADVANCE OF COSTS.

         The Corporation may advance money to any director, officer or other
         individual for the costs, charges and expenses of a proceeding
         referred to in Section 7.02. The individual, however, shall repay the
         moneys to the Corporation if the individual does not fulfil the
         conditions set out in subsection 7.02(a) and, as applicable,
         subsection 7.02(b).

7.04     INSURANCE.

         Subject to the Act, the Corporation may purchase and maintain
         insurance for the benefit of any person referred to in section 7.02
         against any liability incurred by such person in their capacity as a
         director or officer of the Corporation or of another body corporate
         where the individual acts or acted in that capacity at the
         Corporation's request.

<PAGE>


Item 8.  Exhibits

EXHIBIT           DESCRIPTION
-------           -----------

4.1               By-Law No. 2 of the Registrant enacted December 9, 2003, being
                  a by-law relating generally to the transaction of the business
                  and affairs of the Registrant (filed as Exhibit 3.9 to Form
                  10-K, filed February 20, 2004 by the Registrant and
                  incorporated by reference herein)

4.2               Amended and Restated Shareholder Rights Plan Agreement dated
                  May 2, 2002 between the Corporation and CIBC Mellon Trust
                  Company, as Rights Agent, which includes the Form of Rights
                  Certificate as Exhibit A (filed as Exhibit 3 to Form 8-A/A
                  dated August 20, 2002, filed by the Registrant and
                  incorporated by reference herein)

4.3*              Tandem Option Plan

5.1*              Opinion of Blake, Cassels & Graydon LLP, Canadian counsel to
                  Nexen Inc.

23.1*             Consent of Blake, Cassels & Graydon LLP, Canadian counsel to
                  Nexen Inc.

23.2*             Consent of Deloitte & Touche LLP

24.1              Powers of Attorney (included on the signature pages to this
                  registration statement)

*    Filed herewith

<PAGE>


                                  SIGNATURES

                  Pursuant to the requirements of the Securities Act of 1933,
the registrant certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Calgary, Province of Alberta, on September 24,
2004.


                                             NEXEN INC.


                                             By: /s/ John B. McWilliams
                                                 ----------------------------
                                                 John B. McWilliams, Q.C.
                                                 Senior Vice President,
                                                 General Counsel and Secreatary



                               POWER OF ATTORNEY


                  The officers and directors of Nexen Inc. whose signatures
appear below hereby constitute and appoint John B. McWilliams and Charles W.
Fischer, and each of them (with full power to each of them to act alone),
their true and lawful attorneys-in-fact, with full powers of substitution and
resubstitution, to sign and execute on behalf of the undersigned any and all
amendments, including any post-effective amendments, to this Registration
Statement, and to file the same, with exhibits thereto, and other documents in
connection therewith, with the Securities and Exchange Commission, and each of
the undersigned does hereby ratify and confirm all that said attorneys-in-fact
shall do or cause to be done by virtue thereof.

                  Pursuant to the requirements of the Securities Act of 1933,
this Registration Statement has been signed by the following persons in the
capacities indicated effective September 24, 2004:

           SIGNATURE                                 TITLE
           ---------                                 -----

   /s/ Charles W. Fischer        President, Chief Executive Officer and Director
-----------------------------    (Principal Executive Officer)
       Charles W. Fischer


   /s/ Dennis G. Flanagan        Director
-----------------------------
       Dennis G. Flanagan


                                 Director
-----------------------------
       David A. Hentschel

<PAGE>


                                 Director
-----------------------------
       S. Barry Jackson


   /s/ Kevin J. Jenkins          Director
-----------------------------
       Kevin J. Jenkins


                                 Director
-----------------------------
       Eric P. Newell


   /s/ Thomas C. O'Neill         Director
-----------------------------
       Thomas C. O'Neill


   /s/ Francis M. Saville        Director
-----------------------------
       Francis M. Saville


   /s/ Richard M. Thomson        Director
-----------------------------
       Richard M. Thomson


   /s/ John M. Willson           Director
-----------------------------
       John M. Willson


   /s/ Victor J. Zaleschuk       Director
-----------------------------
       Victor J. Zaleschuk


   /s/ Marvin F. Romanow         Executive Vice President and
-----------------------------    Chief Financial Officer
       Marvin F. Romanow         (Principal Financial Officer)


   /s/ Michael J. Harris         Controller
-----------------------------    (Controller and Principal Accounting Officer)
       Michael J. Harris



<PAGE>


                           AUTHORIZED REPRESENTATIVE

                  Pursuant to the requirements to Section 6(a) of the Securities
Act, the undersigned has signed this Registration Statement solely in the
capacity of the duly authorized representative of the Registrant in the United
States on September 24, 2004.


                                        Nexen Petroleum U.S.A. Inc.


                                        By: /s/ Douglas B. Otten
                                            -------------------------------
                                            Douglas B. Otten
                                            President and Chairman of the Board



<PAGE>


                                 EXHIBIT INDEX

EXHIBIT           DESCRIPTION
-------           -----------

4.1               By-Law No. 2 of the Registrant enacted December 9, 2003, being
                  a by-law relating generally to the transaction of the business
                  and affairs of the Registrant (filed as Exhibit 3.9 to Form
                  10-K, filed February 20, 2004 by the Registrant and
                  incorporated by reference herein)

4.2               Amended and Restated Shareholder Rights Plan Agreement dated
                  May 2, 2002 between the Corporation and CIBC Mellon Trust
                  Company, as Rights Agent, which includes the Form of Rights
                  Certificate as Exhibit A (filed as Exhibit 3 to Form 8-A/A
                  dated August 20, 2002, filed by the Registrant and
                  incorporated by reference herein)

4.3*              Tandem Option Plan

5.1*              Opinion of Blake, Cassels & Graydon LLP, Canadian counsel to
                  Nexen Inc.

23.1*             Consent of Blake, Cassels & Graydon LLP, Canadian counsel to
                  Nexen Inc.

23.2*             Consent of Deloitte & Touche LLP

24.1              Powers of Attorney (included on the signature pages to this
                  registration statement)

*    Filed herewith
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As filed with the Securities and Exchange Commission on
                                                           September 24, 2004.
==============================================================================
                                                 Registration No: 333-________

                      SECURITIES AND EXCHANGE COMMISSION
                            Washington, D.C. 20549

                                   FORM S-8
            REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933

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

            CANADA                                        98-6000202
(State or other jurisdiction of                (IRS Employer Identification No.)
incorporation or organization)

                             ____________________

                             801 - 7th Avenue S.W.
                       Calgary, Alberta, Canada T2P 3P7

              (Address, including zip code, and telephone number,
       including area code, of registrant's principal executive offices)

                              Tandem Option Plan
                           (Full title of the plan)

                          Nexen Petroleum U.S.A. Inc.
                               12790 Merit Drive
                                    Suite 800
                              Dallas, Texas 75251
                    (Name and address of agent for service)

                                (972) 450-4600
         (Telephone number, including area code, of agent for service)

                             ____________________
COPIES TO:
John B. McWilliams                                               Edwin S. Maynard
Senior Vice President, General Counsel and Secretary                               Andrew J. Foley
                   Nexen Inc.                                     Paul, Weiss, Rifkind, Wharton & Garrison LLP
            801 - 7th Avenue S.W.                                        1285 Avenue of the Americas
     Calgary, Alberta, Canada T2P 3P7                                  New York, New York 10019-6064
CALCULATION OF REGISTRATION FEE
===============================================================================================================================
                                                              Proposed Maximum     Proposed Maximum
              Title of                    Amount to be         Offering Price     Aggregate Offering          Amount of
    Securities to be Registered         Registered (1)(2)       Per Share (3)            Price            Registration Fee
-------------------------------------------------------------------------------------------------------------------------------
Common Shares, no par value             2,750,000 shares           $38.90            $106,975,000              $13,554
-------------------------------------------------------------------------------------------------------------------------------
1)    This Registration Statement also applies to rights under the Registrant's
      Shareholder Rights Plan Agreement, which are attached to and tradable only
      with the common shares registered hereby. No registration fees are
      required for such rights as they will be issued for no additional
      consideration.

(2)   This Registration Statement shall, in accordance with Rule 416 under the
      Securities Act of 1933, as amended, be deemed to cover such additional
      shares as may be issued to prevent dilution resulting from stock splits,
      stock dividends or similar transactions.

(3)   Calculated in accordance with Rule 457(c) and (h)(1) under the Securities
      Act, as amended, and equal to the average of the high and low prices
      reported on the New York Stock Exchange on September 20, 2004, a date
      within five business days of the filing of this Registration Statement.
EXPLANATORY NOTE

                  We are filing this registration statement for the purpose of
registering, in accordance with General Instruction E of Form S-8, an
additional 2,750,000 Common Shares, no par value, to be issued under the
Registrant's Tandem Option Plan, formerly known as the Amended and Restated
Stock Option Plan. We incorporate by reference into this registration
statement on Form S-8 our previously filed registration statement on Form S-8,
as amended (File No. 333-13574, filed on May 31, 2001 and amended on September
12, 2003) in its entirety, including the exhibits to it.

                                    PART II

              INFORMATION REQUIRED IN THE REGISTRATION STATEMENT

Item 6.  Indemnification of Directors and Officers

                  Section 124 of the Canada Business Corporations Act provides
as follows:

124.     (1)      Indemnification. A corporation may indemnify a director or
                  officer of the corporation, a former director or officer of
                  the corporation or another individual who acts or acted at the
                  corporation's request as a director or officer, or an
                  individual acting in a similar capacity, of another entity,
                  against all costs, charges and expenses, including an amount
                  paid to settle an action or satisfy a judgment, reasonably
                  incurred by the individual in respect of any civil, criminal,
                  administrative, investigative or other proceeding in which the
                  individual is involved because of that association with the
                  corporation or other entity.

         (2)      Advance of Costs. A corporation may advance moneys to a
                  director, officer or other individual for the costs, charges
                  and expenses of a proceeding referred to in subsection (1).
                  The individual shall repay the moneys if the individual does
                  not fulfil the conditions of subsection (3).

         (3)      Limitation. A corporation may not indemnify an individual
                  under subsection (1) unless the individual

                  (a)      acted honestly and in good faith with a view to the
                           best interests of the corporation, or, as the case
                           may be, to the best interests of the other entity
                           for which the individual acted as director or
                           officer or in a similar capacity at the
                           corporation's request; and

                  (b)      in the case of a criminal or administrative action
                           or proceeding that is enforced by a monetary
                           penalty, the individual had reasonable grounds for
                           believing that the individual's conduct was lawful.

         (4)      Indemnification in derivative actions. A corporation may with
                  the approval of a court, indemnify an individual referred to
                  in subsection (1), or advance moneys under subsection (2), in
                  respect of an action by or on behalf of the corporation or
                  other entity to procure a judgment in its favour, to which the
                  individual is made a party because of the individual's
                  association with the corporation or other entity as described
                  in subsection (1) against all costs, charges and expenses
                  reasonably incurred by the individual in
connection with such action, if the individual fulfills the
                  conditions set out in subsection (3).

         (5)      Right to indemnity. Despite subsection (1), an individual
                  referred to in that subsection is entitled to indemnity from
                  the corporation in respect of all costs, charges and
                  expenses reasonably incurred by the individual in connection
                  with the defence of any civil, criminal, administrative,
                  investigative or other proceeding to which the individual is
                  subject because of the individual's association with the
                  corporation or other entity as described in subsection (1),
                  if the individual seeking indemnity

                  (a)      was not judged by the court or other competent
                           authority to have committed any fault or omitted to
                           do anything that the individual ought to have done;
                           and

                  (b)      fulfills the conditions set out in subsection (3).

         (6)      Insurance. A corporation may purchase and maintain insurance
                  for the benefit of an individual referred to in subsection
                  (1) against any liability incurred by the individual

                  (a)      in the individual's capacity as a director or
                           officer of the corporation; or

                  (b)      in the individual's capacity as a director or
                           officer, or similar capacity, of another entity, if
                           the individual acts or acted in that capacity at
                           the corporation's request.

         (7)      Application to court. A corporation, an individual or an
                  entity referred to in subsection (1) may apply to a court
                  for an order approving an indemnity under this section and
                  the court may so order and make any further order that it
                  sees fit.

         (8)      Notice to Director. An applicant under subsection (7) shall
                  give the Director notice of the application and the Director
                  is entitled to appear and be heard in person or by counsel.

         (9)      Other notice. On an application under subsection (7) the
                  court may order notice to be given to any interested person
                  and the person is entitled to appear and be heard in person
                  or by counsel.

                  Section 7 of the By-laws of the Registrant contains the
following provisions with respect to indemnification of the Registrant's
directors and officers and with respect to certain insurance maintained by the
Registrant with respect to its indemnification obligations:

7.01     LIMITATION OF LIABILITY.

         Every director and officer of the Corporation shall act honestly and
         in good faith with a view to the best interests of the Corporation
         and shall exercise the care, diligence and skill that a reasonably
         prudent person would exercise in comparable circumstances, including
         reliance in good faith on:

                  (a)      financial statements of the Corporation represented
                           to the director by an officer of the Corporation or
                           in a written report of the auditor of the
                           Corporation fairly to reflect the financial
                           condition of the Corporation; or
                  (b)      a report of a person whose profession lends
                           credibility to a statement made by the professional
                           person.
Subject to the above provisions, no director or officer is liable for
         the acts, receipts, neglects or defaults of any other director,
         officer or employee, or for joining in any receipt or other act for
         conformity, or for any loss, damage or expense happening to the
         Corporation through the insufficiency or deficiency of title to any
         property acquired for or on behalf of the Corporation, or for the
         insufficiency or deficiency of any security in or upon which any of
         the moneys of the Corporation are invested, or for any loss or damage
         arising from the bankruptcy, insolvency or tortious acts of any
         person with whom any of the moneys, securities or effects of the
         Corporation are deposited, or for any loss occasioned by any error of
         judgement or oversight on the part of the director or officer, or for
         any other loss, damage or misfortune which happens in the execution
         of the duties of the office of the director or officer; provided that
         nothing in this section relieves any director or officer from the
         duty to act in accordance with the Act or from liability for any
         breach thereof.

7.02     INDEMNITY.

         Subject to the provisions of the Act, the Corporation shall indemnify
         a director or officer, a former director or officer, or another
         individual who acts or acted at the Corporation's request as a
         director or officer, or an individual acting in a similar capacity of
         another entity, against all costs, charges and expenses, including an
         amount paid to settle an action or satisfy a judgement, reasonably
         incurred by the individual in respect of any civil, criminal,
         administrative or investigative action or other proceeding in which
         the individual is involved because of that association with the
         Corporation or other entity if, exercising the care, diligence and
         skill that a reasonably prudent person would exercise in comparable
         circumstances:

                                    (a) the individual acted honestly and in
                  good faith with a view to the best interests of the
                  Corporation or, as the case may be, to the best interests of
                  the other entity for which the individual acted as director
                  or officer or in a similar capacity at the Corporation's
                  request; and

                                    (b) in the case of a criminal or
                  administrative action or proceeding that is enforced by a
                  monetary penalty, the individual had reasonable grounds for
                  believing that the individual's conduct was lawful.

         The Corporation shall also indemnify any of the other persons set out
         above in any other circumstances which the Act or law permits or
         requires. Nothing in this by-law limits the right of any person
         entitled to indemnity to claim indemnity apart from the provisions of
         this by-law to the extent permitted by the Act or law.

7.03     ADVANCE OF COSTS.

         The Corporation may advance money to any director, officer or other
         individual for the costs, charges and expenses of a proceeding
         referred to in Section 7.02. The individual, however, shall repay the
         moneys to the Corporation if the individual does not fulfil the
         conditions set out in subsection 7.02(a) and, as applicable,
         subsection 7.02(b).

7.04     INSURANCE.

         Subject to the Act, the Corporation may purchase and maintain
         insurance for the benefit of any person referred to in section 7.02
         against any liability incurred by such person in their capacity as a
         director or officer of the Corporation or of another body corporate
         where the individual acts or acted in that capacity at the
         Corporation's request.
Item 8.  Exhibits

EXHIBIT           DESCRIPTION
-------           -----------

4.1               By-Law No. 2 of the Registrant enacted December 9, 2003, being
                  a by-law relating generally to the transaction of the business
                  and affairs of the Registrant (filed as Exhibit 3.9 to Form
                  10-K, filed February 20, 2004 by the Registrant and
                  incorporated by reference herein)

4.2               Amended and Restated Shareholder Rights Plan Agreement dated
                  May 2, 2002 between the Corporation and CIBC Mellon Trust
                  Company, as Rights Agent, which includes the Form of Rights
                  Certificate as Exhibit A (filed as Exhibit 3 to Form 8-A/A
                  dated August 20, 2002, filed by the Registrant and
                  incorporated by reference herein)

4.3*              Tandem Option Plan

5.1*              Opinion of Blake, Cassels & Graydon LLP, Canadian counsel to
                  Nexen Inc.

23.1*             Consent of Blake, Cassels & Graydon LLP, Canadian counsel to
                  Nexen Inc.

23.2*             Consent of Deloitte & Touche LLP

24.1              Powers of Attorney (included on the signature pages to this
                  registration statement)

*    Filed herewith
SIGNATURES

                  Pursuant to the requirements of the Securities Act of 1933,
the registrant certifies that it has reasonable grounds to believe that it meets
all of the requirements for filing on Form S-8 and has duly caused this
Registration Statement to be signed on its behalf by the undersigned, thereunto
duly authorized, in the City of Calgary, Province of Alberta, on September 24,
2004.

                                             NEXEN INC.

                                             By: /s/ John B. McWilliams
                                                 ----------------------------
                                                 John B. McWilliams, Q.C.
                                                 Senior Vice President,
                                                 General Counsel and Secreatary

                               POWER OF ATTORNEY

                  The officers and directors of Nexen Inc. whose signatures
appear below hereby constitute and appoint John B. McWilliams and Charles W.
Fischer, and each of them (with full power to each of them to act alone),
their true and lawful attorneys-in-fact, with full powers of substitution and
resubstitution, to sign and execute on behalf of the undersigned any and all
amendments, including any post-effective amendments, to this Registration
Statement, and to file the same, with exhibits thereto, and other documents in
connection therewith, with the Securities and Exchange Commission, and each of
the undersigned does hereby ratify and confirm all that said attorneys-in-fact
shall do or cause to be done by virtue thereof.

                  Pursuant to the requirements of the Securities Act of 1933,
this Registration Statement has been signed by the following persons in the
capacities indicated effective September 24, 2004:

           SIGNATURE                                 TITLE
           ---------                                 -----

   /s/ Charles W. Fischer        President, Chief Executive Officer and Director
-----------------------------    (Principal Executive Officer)
       Charles W. Fischer

   /s/ Dennis G. Flanagan        Director
-----------------------------
       Dennis G. Flanagan

                                 Director
-----------------------------
       David A. Hentschel
Director
-----------------------------
       S. Barry Jackson

   /s/ Kevin J. Jenkins          Director
-----------------------------
       Kevin J. Jenkins

                                 Director
-----------------------------
       Eric P. Newell

   /s/ Thomas C. O'Neill         Director
-----------------------------
       Thomas C. O'Neill

   /s/ Francis M. Saville        Director
-----------------------------
       Francis M. Saville

   /s/ Richard M. Thomson        Director
-----------------------------
       Richard M. Thomson

   /s/ John M. Willson           Director
-----------------------------
       John M. Willson

   /s/ Victor J. Zaleschuk       Director
-----------------------------
       Victor J. Zaleschuk

   /s/ Marvin F. Romanow         Executive Vice President and
-----------------------------    Chief Financial Officer
       Marvin F. Romanow         (Principal Financial Officer)

   /s/ Michael J. Harris         Controller
-----------------------------    (Controller and Principal Accounting Officer)
       Michael J. Harris
AUTHORIZED REPRESENTATIVE

                  Pursuant to the requirements to Section 6(a) of the Securities
Act, the undersigned has signed this Registration Statement solely in the
capacity of the duly authorized representative of the Registrant in the United
States on September 24, 2004.

                                        Nexen Petroleum U.S.A. Inc.

                                        By: /s/ Douglas B. Otten
                                            -------------------------------
                                            Douglas B. Otten
                                            President and Chairman of the Board
EXHIBIT INDEX

EXHIBIT           DESCRIPTION
-------           -----------

4.1               By-Law No. 2 of the Registrant enacted December 9, 2003, being
                  a by-law relating generally to the transaction of the business
                  and affairs of the Registrant (filed as Exhibit 3.9 to Form
                  10-K, filed February 20, 2004 by the Registrant and
                  incorporated by reference herein)

4.2               Amended and Restated Shareholder Rights Plan Agreement dated
                  May 2, 2002 between the Corporation and CIBC Mellon Trust
                  Company, as Rights Agent, which includes the Form of Rights
                  Certificate as Exhibit A (filed as Exhibit 3 to Form 8-A/A
                  dated August 20, 2002, filed by the Registrant and
                  incorporated by reference herein)

4.3*              Tandem Option Plan

5.1*              Opinion of Blake, Cassels & Graydon LLP, Canadian counsel to
                  Nexen Inc.

23.1*             Consent of Blake, Cassels & Graydon LLP, Canadian counsel to
                  Nexen Inc.

23.2*             Consent of Deloitte & Touche LLP

24.1              Powers of Attorney (included on the signature pages to this
                  registration statement)

*    Filed herewith