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                                                            EXHIBIT 10(b)(xxiii)

                         ANADARKO PETROLEUM CORPORATION

                            1999 STOCK INCENTIVE PLAN
                             STOCK OPTION AGREEMENT
                                 (Class Vesting)

     1. To the extent that the right to exercise Options has accrued hereunder,
the Options, or any part thereof, may be exercised in whole or in part by filing
a written notice with the Corporate Secretary of the Company at its corporate
headquarters. Such notice shall be in the form specified by the Committee. If no
form has been specified, such notice shall specify the number of Options that
the Participant wants to exercise and the method of exercise. Payments of all
amounts due shall be made by check payable to the Company. Except as otherwise
provided by the Committee before an Option is exercised: (i) all or a portion of
the Exercise Price may be paid by delivery of Mature Shares having an aggregate
Fair Market Value (valued as of the date of exercise) that is equal to the
amount of cash that would otherwise be required; and (ii) the Participant may
pay the Exercise Price by authorizing a third party to sell Shares (or a
sufficient portion of the Shares) acquired upon exercise of the Option and remit
to the Company a sufficient portion of the sale proceeds to pay the entire
Exercise Price and any tax withholding resulting from such exercise. No Shares
shall be issued or delivered until full payment therefor has been made.

     2. The Options may not be exercised unless the Participant is at the time
of such exercise an employee of the Company, or an Affiliate, and shall have
been continuously employed by the Company, or an Affiliate, since the date the
Options were granted; provided, however, that the Options shall be exercisable
following the termination of the Participant's employment during the term of the
Options as provided in sections (i) through (iv) below. Options, which are not
and do not become exercisable at the time of the Participants termination of
employment shall, coincident therewith, terminate and be of no further force or
effect.

          (i) Retirement or Disability. If the Participant shall cease to be an
     employee of the Company, or an Affiliate, by reason of (a) retirement
     pursuant to a pension or retirement plan of the Company, or of a
     subsidiary, or (b) disability, as defined in the Company's disability plan,
     the Participant (or, in the event of Participant's death, the Participant's
     legal representative) may, within a period of not more than thirty-six (36)
     months after the date of cessation of employment, exercise the Options if
     and to the extent they were exercisable on the date of cessation. In no
     event may the Options be exercised more than ten (10) years from the date
     of grant.

          (ii) Death of Participant. In the event of the death of the
     Participant while an active employee of the Company, or an Affiliate, any
     outstanding Options granted to the Participant shall vest and be
     immediately exercisable with respect to all or any part of the Options
     which remain unexercised. The Participant's legal representative or other
     person or persons to whom the Participant's rights under the Options shall
     pass by the Participant's will or the laws of descent and distribution,
     may, within a period of not more than twelve (12) months after the date of
     death, exercise the Options. In no event may the Options be exercised more
     than ten (10) years from the date of grant.

          (iii) Termination Without Cause. If the Participant's employment with
     the Company, or an Affiliate, is terminated by the Company or an



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     Affiliate due to a reduction in force, job abolishment, or at the
     convenience of the Company, or an Affiliate as determined by the Committee,
     the Participant (or, in the event of the Participant's death, the
     Participant's legal representative) may, within a period of not more than
     three (3) months after such cessation of employment, exercise the Options
     if and to the extent they were exercisable at the date of such cessation.
     In no event may the Options be exercised more than ten (10) years from the
     date of grant.

          (iv) Termination following Change of Control. If the Participant's
     employment with the Company, or an Affiliate, is terminated following
     Change of Control and the Participant received a benefit under the Key
     Employee Change of Control Contract or the Change of Control Severance Pay
     Plan, the Participant (or, in the event of the Participant's death, the
     Participant's legal representative) may, within a period of not more than
     three (3) months after such cessation of employment, exercise the Options
     if and to the extent they were exercisable at the date of such cessation.
     In no event may the Options be exercised more than ten (10) years from the
     date of grant.

Notwithstanding anything to the contrary, if the Participant is terminated by
the Company, or an Affiliate, as provided in (iii) and (iv) above and the
Participant qualifies for retirement under the Company's retirement plan, the
Participant shall be deemed to have terminated because of retirement.

The Committee may, under unusual circumstances and pursuant to the Plan,
accelerate the time at which Options may be exercised.

     3. The Options granted hereunder are not transferable by the Participant
except by will or the laws of descent and distribution. Options are exercisable,
during the Participant's lifetime, only by the Participant. Upon any attempt to
transfer, assign, pledge, hypothecate or otherwise dispose of the Options, or of
any right or privilege conferred hereby, contrary to the provisions hereof, or
upon the levy of any attachment or similar process upon the Options or any right
or privilege conferred hereby, the Options and the right and privilege conferred
hereby shall immediately become null and void.

     4. The Options may be adjusted or required to be surrendered pursuant to
the provisions of the 1999 Stock Incentive Plan.

     5. The Participant shall have no rights as a stockholder with respect to
any Shares subject to the Options prior to the date of issuance to the
Participant of a certificate or certificates for such Shares.

     6. The Participant shall be considered to be in the employment of the
Company, or an Affiliate, as long as the Participant remains an employee of
either the Company, or and Affiliate, or a corporation or a parent or subsidiary
of such corporation assuming or substituting a new option for this Option. Any
question as to whether and when there has been a termination of such employment,
and the cause of such termination, shall be determined either by the Committee
or the Board of Directors of the employing corporation, and its determination
shall be final. Nothing herein contained shall confer upon the Participant any
right with respect to continuance of employment by the Company, or an Affiliate,
or interfere in any way with the right of the Company, or an Affiliate, to
terminate the Participant's service, responsibilities, duties and authority to
represent the Company or such Affiliate at any time, in its sole discretion and
with or without cause.

     7. If at any time the Company shall determine in its discretion that the
listing or qualification of Shares subject hereto under any securities

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exchange requirements or under any applicable state or federal law, or the
consent or approval of any governmental regulatory body, is necessary or
desirable as a condition of, or in connection with, the granting of the Options
or the issue of Shares hereunder, the Options may not be exercised in whole or
in part unless such listing, qualification, consent or approval shall have been
effected or obtained free of any conditions not acceptable to the Company.

     8. All distributions under this Agreement are subject to withholding of all
applicable taxes. At the election of the Participant, and subject to such rules
as may be established by the Committee, such withholding obligations may be
satisfied through the surrender of Shares which the Participant already owns, or
to which the Participant is otherwise entitled to under the Plan.

     9. This Agreement shall be binding upon and inure to the benefit of the
parties hereto and their successors, but neither this Agreement nor any rights
hereunder shall be assignable by the Participant except as specifically provided
for herein.

     10. Unless otherwise specifically defined herein, each term used herein
which is defined in the 1999 Stock Incentive Plan shall have the meaning
assigned such term in the 1999 Stock Incentive Plan.

     11. This Agreement may be amended by agreement of the Participant and the
Company, without the consent of any other person.

     12. This Agreement shall be governed by, and construed in accordance with
the laws of the State of Texas.

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