EXHIBIT 10.6(b)
 
VASTAR RESOURCES, INC.
___________________________________________________

Supplementary Executive Retirement Plan

As Amended and Restated Effective March 24, 1999

 
                            VASTAR RESOURCES, INC.
                    SUPPLEMENTARY EXECUTIVE RETIREMENT PLAN


 
                                 TABLE OF CONTENTS
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ARTICLE I

 Section 1.1       Purpose and Intent of Plan...........................................................    1
 Section 1.2       Effective Date of Plan...............................................................    1
 Section 1.3       Definitions..........................................................................    1
 Section 1.4       Costs of Plan........................................................................    4

ARTICLE II         SUPPLEMENTAL BENEFIT DEFERRED SALARY AND ANNUAL INCENTIVE AWARDS

 Section 2.1       Eligibility..........................................................................    5
 Section 2.2       Amount of Benefit....................................................................    5

ARTICLE III        

 Section 3.1       Eligibility..........................................................................    8
 Section 3.2       Amount of Benefit....................................................................    8

ARTICLE IV         SPECIAL SUPPLEMENTAL RETIREMENT BENEFITS.............................................   10

ARTICLE V          FORM AND TIMING OF BENEFIT
 Section 5.1       Benefits Payable Under Articles II and III...........................................   11
 Section 5.2       Benefits Payable Under Article IV....................................................   12
 Section 5.3       Benefits Payable After a Change of Control...........................................   12

ARTICLE VI         ADMINISTRATION

 Section 6.1       Rules of Conduct.....................................................................   14
 Section 6.2       Legal, Accounting, Clerical and Other Services.......................................   14
 Section 6.3       Interpretation of Provisions.........................................................   14
 Section 6.4       Records of Administration............................................................   14
 Section 6.5       Denial of Claim......................................................................   14
 Section 6.6       Liability of Committee...............................................................   14
 

 
 
 

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ARTICLE VII        FACILITY OF PAYENT AND LAPSE OF BENEFITS

 Section 7.1       Provisions for Incapacity............................................................   15
 Section 7.2       Payments of Deposits.................................................................   15

ARTICLE VII        MISCELLANEOUS

 Section 8.1       Unfunded Benefit Plan................................................................   16
 Section 8.2       Grantor Trust........................................................................   16
 Section 8.3       Payments and Benefits Not Assignable.................................................   16
 Section 8.4       No Right of Employment...............................................................   16
 Section 8.5       Adjustments..........................................................................   17
 Section 8.6       Obligation to Company................................................................   17
 Section 8.7       Protective Provisions................................................................   17
 Section 8.8       Gender, Singular and Plural..........................................................   17
 Section 8.9       Law Governing........................................................................   17
 Section 8.10      Validity.............................................................................   17
 Section 8.11      Notice...............................................................................   18
 Section 8.12      Successors and Assigns...............................................................   18
 Section 8.13      Tax Withholding......................................................................   18

ARTICLE IX         AMENDMENT AND TERMINATION

 Section 9.1       Amendment of Plan....................................................................   19
 Section 9.2       Termination..........................................................................   19
 Section 9.3       Effect of Amendment or Termination...................................................   19

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                                   ARTICLE I

                              GENERAL PROVISIONS


1.1  PURPOSE AND INTENT OF PLAN

     (a) This Plan is adopted in conjunction with the Atlantic Richfield Company
         Supplementary Executive Retirement Plan. Recognizing that an Employee
         may transfer between Vastar Resources, Inc. and Atlantic Richfield
         Company during his or her service, each company has agreed to pay a pro
         rata share of the Employee's benefit as described under Articles II and
         III of each Plan.

     (b) This Plan is intended to provide supplemental retirement allowances in
         accordance with the provisions of the Plan contained herein, to those 
         Employees who:

          (1) Have received an award under the Vastar Resources, Inc. Annual
              Incentive Plan or the Atlantic Richfield Company Annual Incentive
              Plan.

          (2) Have deferred a portion of their Salary under the Vastar
              Resources, Inc. Executive Deferral Plan or the Atlantic Richfield 
              Company Executive Deferral Plan.

          (3) Have had the amount of their retirement benefit reduced due to
              federal legal requirements, under a tax-qualified, defined benefit
              retirement plan maintained by Vastar Resources, Inc. or Atlantic
              Richfield Company, or

          (4) Have been granted a Special Supplemental Retirement Benefit in
              accordance with the provisions of this Plan.

1.2  EFFECTIVE DATE OF PLAN

          The Plan was originally adopted effective June 26, 1994.  This Plan as
amended and restated shall be effective as of March 24, 1999. 

1.3  DEFINITIONS

     (a) "Actuarial Equivalent" means, in comparing benefits payable in
     different forms or at different times or in different circumstances, a
     value under one such set of circumstances which is the same as the value
     under a different set of circumstances. Such value shall be computed and
     determined with reference to 

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     mortality assumptions, interest rates and other actuarial factors and
     assumptions then in effect under the Retirement Plan for the purpose of
     calculating the actuarial equivalent under that Plan.

     (b) "Administrator" means (1) prior to the earlier to occur of a Change of
     Control or an Anticipatory Change of Control, Vastar Resources, Inc. or the
     Administrative Committee, and (2) on and after the earlier to occur of a
     Change of Control or an Anticipatory Change of Control, the Special Plan
     Administrator, which shall also assume all powers and duties of the
     Administrator under the Plan. Upon a written determination by the Chief
     Financial Officer and the General Counsel of the Company, approved by
     either the Board of Directors of the Company (the "Board"), the Outside
     Directors or the Executive Committee of the Board, that an Anticipatory
     Change of Control has ended without concluding in a Change of Control (an
     "Anticipatory Change Termination"), Vastar Resources, Inc. or the
     Administrative Committee will again become the Administrator. For purposes
     of this definition a Change of Control shall not include an ARCO
     Acquisition.

     (c) "Administrative Committee" means the Retirement Plan Committee of the
     Vastar Retirement Plan or such other committee as shall be appointed by the
     Vice President, Human Resources of the Company.

     (d) "Anticipatory Change of Control" shall be ascribed the meaning set
     forth for such term in Annex A attached hereto.

     (e) "ARCO" means Atlantic Richfield Company.

     (f) "ARCO Acquisition" shall mean a change of control as defined in
     paragraph (3) of the definition of Change of Control on Annex A attached
     hereto.

     (g) "ARCO Takeover" shall mean a change of control as defined in paragraph
     (5) of the definition of Change of Control on Annex A attached hereto.

     (h) "Awards" means an award made under the Vastar Resources, Inc. Annual
     Incentive Plan or the Atlantic Richfield Company Annual Incentive Plan,
     whether paid in cash or deferred.

     (i) "Base Pay" means "Annual Base Pay" as defined in the Retirement Plan.

     (j) "Basic Allowance" means an annuity payable for the life of the
     Participant, with a guarantee that an amount equal to 60 monthly payments
     will be paid to the Participant and his or her Beneficiary.

     (k) "Beneficiary" means a person who is entitled to receive a Survivor
     Benefit in the event of the Participant's death. The Beneficiary under
     Articles II and III of this Plan shall be the same person.

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     (l) "Change of Control" shall be ascribed the meaning set forth for such
     term as Annex A attached hereto.

     (m) "Code" means the Internal Revenue Code of 1986, as amended.

     (n) "Company" means Vastar Resources, Inc. and any of its subsidiaries.

     (o) "Deferred Compensation" means any amount of Salary which a Participant
     elects to defer pursuant to the provisions of the Vastar Resources, Inc.
     Executive Deferral Plan or the Atlantic Richfield Company Executive
     Deferral Plan.

     (p) "ERISA" means the Employee Retirement Income Security Act of 1974, as
     amended.

     (q) "Employee" means any person who is or was regularly employed by the
     Company.

     (r) "Fifty Percent Joint and Survivor Annuity" means an annuity providing
     payments for the life of a Participant, with a survivor annuity for the
     life of his or her Beneficiary under which each payment to the Beneficiary
     is 50 percent of the amount payable during the life of the Participant.
     Each payment during the life of the Participant shall be a percentage of
     the amount otherwise payable to the Participant in the form of a Basic
     Allowance, so that the Fifty Percent Joint and Survivor Annuity is the
     Actuarial Equivalent of the Basic Allowance otherwise payable to the
     Participant.

     (s) "Financial Hardship" means a condition of financial difficulty,
     determined by the Administrator, upon advice of counsel, to be sufficient
     to justify a change of election of the form of benefit under Article V
     without causing, in the judgment of counsel, the receipt of taxable income
     by any other Participant in the Plan in advance of the payment to him or
     her of Plan benefits.

     (t) "Lump Sum" means a single payment of the benefit which is the Actuarial
     Equivalent of (1) the Basic Allowance, or (2) remaining installments under
     a form of annuity in pay status, as applicable.

     (u) The term "Outside Director" shall be ascribed the meaning set forth
     for such term on Annex A attached hereto.

     (v) "Participant" means a person who is or was an Employee and who (1)
     received an Award during the computation period which would be used in
     computing the Employee's Average Final Base Pay under the Retirement Plans
     if the Award were recognized as a part of Base Pay under the Retirement
     Plans, (2) deferred a portion of his or her Salary during the computation
     period which

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     would be used in calculating the Employee's Average Final Base Pay under
     the Retirement Plans if the Deferred Compensation were recognized as a part
     of Base Pay under the Retirement Plans, (3) has had his or her benefit
     under the Retirement Plans reduced due to required limitations under the
     Code or ERISA and/or (4) is granted a Special Supplemental Retirement
     Benefit pursuant to this Plan.

     (w) "Plan" means this Vastar Resources, Inc. Supplementary Executive
     Retirement Plan.

     (x) "Pre-Retirement Annuity" means the annuity paid under the Retirement
     Plans to a survivor, which is attributable to Company contributions and
     which is payable on account of the Participant's death prior to commencing
     a retirement allowance and following attainment of entitlement to a
     retirement allowance derived from Company contributions.

     (y) "Retirement Plans" means the Vastar Retirement Plan and any defined
     benefit, tax-qualified retirement plan, as defined in (S)3(35) of the ERISA
     and (S)401(a) of the Code, maintained by ARCO.

     (z) "Salary" means the Employee's regular base salary, excluding any Award,
     and any other special or additional compensatory payments made by the
     Company or ARCO.

     (aa) "Secondary Change of Control" shall mean a sale by ARCO (directly or 
     indirectly) within one year after an ARCO Acquisition of 85% or more of the
     assets held by Vastar immediately prior to the ARCO Acquisition.

     (bb) "Special Plan Administrator" shall be ascribed the meaning set forth
     for such term on Annex A attached hereto.

     (cc) "Special Supplemental Retirement Benefit" means a supplementary
     retirement benefit approved for payment under Article IV of this Plan to an
     Employee by the Compensation Committee of the Board of Directors of Vastar
     Resources, Inc.

     (dd) "Survivor Benefit" means the benefit payable upon the death of the
     Participant under Section 2.2(c) or 3.2(c).

     (ee) "Vastar Retirement Plan" means the Vastar Resources, Inc. Retirement
     Plan, and any other defined benefit tax-qualified retirement plan, as
     defined in (S)3(35) of ERISA and (S)401(a) of the Code, maintained by the
     Company.

1.4  COSTS OF PLAN

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          All costs of this Plan, including the administration thereof, shall be
borne by the Company and no Employee contributions shall be required or
permitted.

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                                  ARTICLE II

                             SUPPLEMENTAL BENEFIT
                  DEFERRED SALARY AND ANNUAL INCENTIVE AWARD


2.1  ELIGIBILITY

     (a) The following Participants shall automatically be eligible for benefits
         provided by this Article without the necessity for filing an 
         application for such benefits:

          (1) A Participant retiring with an allowance from the Retirement Plans
              which commences immediately (or which could have commenced 
              immediately) upon separation from employment, and

          (2) A Participant terminating employment with a right to an allowance
              from the Retirement Plans commencing on a later date.

     (b) Any person who is designated by the Participant as a Beneficiary will
         be eligible to receive the survivor benefit under Section 2.2(c).
         Benefits under this Article will automatically be paid to such person
         without the necessity for filing an application. In the case of the
         Participant's death prior to commencement of the benefit without his or
         her having designated a Beneficiary, the Beneficiary shall be the
         participant's spouse if the Participant was married at the time of
         death and the Participant's estate if the Participant was single at the
         time of death.

2.2  AMOUNT OF BENEFIT

     (a) GENERAL. The amount of the benefit payable under this Article is a
     portion of the sum of separate, identical benefits prescribed under
     provisions of this Article, and the corresponding provisions of the
     Atlantic Richfield Company Supplementary Executive Retirement Plan, the
     determination of which entails the general calculation of an aggregate
     benefit payable from the Plans, followed by the allocation of a specific
     benefit to this Plan, as described hereafter, which benefit is payable by
     this Plan.

     (b) PARTICIPANT BENEFIT

         (1) GENERAL CALCULATION. The amount of a Participant's monthly benefit
         under this Article will be a percentage, as described in the next
         paragraph of this Subsection, of the difference, if any, between (i)
         the amount of monthly allowance the Participant would have received
         under 

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          the Retirement Plans at retirement, under the Basic Allowance, if the
          Base Pay used in calculating the monthly allowance under the
          Retirement Plans had included each Award made to the Participant in
          each applicable period and the Participant's Deferred Compensation in
          each applicable period, and (ii) the amount of monthly allowance the
          Participant is entitled to receive at retirement from the Retirement
          Plans, under the Basic Allowance under the Retirement Plans.

          (2) SPECIFIC BENEFIT. The percentage of the difference in the monthly
          benefit calculated under Section 2.2(b)(1) of this Article II (which
          shall be the actual retirement benefit payable under this Article)
          shall be the percentage equivalent to a fraction of which the
          numerator is the normal monthly retirement allowance to which the
          Participant is entitled under the Vastar Retirement Plan and the
          denominator of which is the normal monthly retirement allowance to
          which the Participant is entitled under the Retirement Plans.

     (c)  SURVIVOR BENEFIT

          (1)  DEATH OF PARTICIPANT PRIOR TO COMMENCEMENT OF BENEFIT.

               (i) General Calculation. If a Participant who is entitled to
               receive a benefit under this Article dies prior to commencing
               receipt of the benefit, then the Participant's Beneficiary will
               be paid a monthly survivor benefit under this Article equal to a
               percentage, as described in the next paragraph of this
               Subsection, of the difference, if any, between (A) the monthly
               Pre-Retirement Annuity that would have been payable to the
               Participant's Beneficiary under the Retirement Plans if the Base
               Pay used in computing benefits under the Retirement Plans
               included each Award made to the Participant in each applicable
               period and the Participant's Deferred Compensation in each
               applicable period and (B) the monthly Pre-Retirement Annuity
               payable to the Participant's Beneficiary under the Retirement
               Plans.

               (ii) Specific Survivor Benefit. The percentage of the difference
               in the monthly benefit calculation under Section 2.2(c)(1)(i)
               (which shall be the actual survivor benefit payable under this
               Article) shall be the percentage equivalent to a fraction of
               which the numerator is the normal monthly retirement allowance to
               which the Participant would have been entitled under the Vastar
               Retirement Plan and the denominator of which is the normal
               monthly retirement allowance to which the Participant would have
               been entitled to under the Retirement Plans.

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          (2) DEATH OF PARTICIPANT AFTER COMMENCEMENT OF BENEFIT. If a
          Participant dies after commencing receipt of the benefit, then the
          Participant's Beneficiary will be paid a monthly survivor benefit, if
          applicable, pursuant to the Participant's form of allowance elected
          under the Retirement Plans and Article V of this Plan.

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     (d)  MAXIMUM LIMITATION ON BENEFITS

          (1) The benefit calculation under Section 2.2(b)(1) or 2.2(c)(1)(i) of
          this article, as the case may be, shall not cause the annual benefit
          under the form of allowance elected under the Retirement Plans and
          Article III of this Plan, when added to the annual benefit payable
          under this article, and Article II of the Atlantic Richfield Company
          Supplementary Executive Retirement Plan, to exceed 65 percent of the
          greater of (i) the sum of the Participant's annual Salary as of his or
          her termination of employment plus his or her most recent Award, or
          (ii) the average, during the Participant's prior ten years of
          employment, of the Participant's highest three consecutive years of
          Salary (whether or not deferred) and Award in each such year.

          (2) Annuities resulting from voluntary employee contributions to the
          Retirement Plans and increased benefits resulting from election of a
          Level Income Option under the Retirement Plans shall not be considered
          in applying the foregoing limitations.

     (e) COMPUTATION PROCEDURE. For purposes of computing the amount of monthly
     benefit payable under Sections 2.2(b) and 2.2(c) of this Article, it shall
     be assumed that an Award has been made with respect to the calendar year in
     which a Participant's termination or death occurs equal in amount to a pro
     rata share of the Award, if any, made to such Participant with respect to
     the calendar year immediately preceding such year, or if no such Award has
     been made, then equal in amount to a pro rata share of the most recent
     Award made to such Participant (the "Pro Rata Calculation"). If, following
     termination or death and after commencement of benefits under this Article,
     the Participant (or the Participant's estate or beneficiary) receives an
     Award with respect to the year of termination or death, the benefit under
     this Article shall be recalculated to take into account such Award,
     provided however, that such recalculation shall not result in a reduction
     of the benefit that has commenced under this Article. If, following
     termination or death and after commencement of benefits under this Article,
     the Participant (or the Participant's estate or beneficiary) receives an
     Award with respect to the year immediately preceding the year of
     termination or death, the benefit payable under this Article (including the
     Pro Rata Calculation, if applicable) shall be recalculated to take into
     account such Award provided however, that such recalculation shall not
     result in a reduction of the benefit that has commenced under this Article.


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     (f) SEPARATION FROM EMPLOYMENT. Unless a Participant at the time of
     separation from Company employment is eligible for an immediate or deferred
     retirement allowance from the Retirement Plans or unless a survivor benefit
     is payable under Section 2.2(c) of this Article upon the death of the
     Participant, rights of the Participant, and any person claiming under or by
     right of the Participant, to any benefits under this Article shall cease
     upon the Participant's separation from the employment of the Company.

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                                  ARTICLE III

                             SUPPLEMENTAL BENEFIT
              LEGALLY REQUIRED LIMITATIONS UNDER QUALIFIED PLANS
                                        

3.1  ELIGIBILITY

     (a) The following Participants shall automatically be eligible for benefits
     provided by this Article without the necessity for filing an application
     for such benefits:

          (1) A Participant retiring on an allowance from the Retirement Plans
          which commences immediately (or which could have commenced
          immediately) upon separation from employment, and

          (2) A Participant terminating employment with a right to an allowance
          from the Retirement Plans commencing on a later date.

     (b) Any person who is designated by the Participant as a Beneficiary will
     be eligible to receive the survivor benefit under Section 3.2(c). Benefits
     under this Article will automatically be paid to such person without the
     necessity for filing an application. In the case of the Participant's death
     prior to commencement of the benefit without his or her having designated a
     Beneficiary, the Beneficiary shall be the Participant's spouse if the
     Participant was married at the time of death, and the Participant's estate
     if the Participant was single at the time of death.

3.2  AMOUNT OF BENEFIT

     (a) GENERAL. The amount of the benefit payable under this Article is a
     portion of the sum of separate, identical benefits prescribed under
     provisions of this Article, and the corresponding provisions of the
     Atlantic Richfield Company Supplementary Executive Retirement Plan, the
     determination of which entails the general calculation of an aggregate
     benefit payable from the Plans, followed by the allocation of a specific
     benefit to this Plan, as described hereafter, which benefit is payable by
     this Plan.

     (b) PARTICIPANT BENEFIT

         (1) GENERAL CALCULATION. The amount of a Participant's monthly benefit
         under this Article will be a percentage, as described in the next
         paragraph of this Subsection, of the difference, if any, between (i)
         the amount of monthly allowance the Participant would have received
         under the Retirement Plans at retirement, under the Basic Allowance,
         if the calculation of the benefit were not subject to limitations or
         reductions required under the Code or ERISA, and (ii) the amount of
         monthly 

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          allowance the Participant is entitled to receive at retirement from
          the Retirement Plans, under the Basic Allowance under the Retirement
          Plans.

          (2) SPECIFIC BENEFIT. The percentage of the difference in the monthly
          benefit calculated under Section 3.2(b)(1) (which shall be the actual
          retirement benefit payable under this Article) shall be the percentage
          equivalent to a fraction of which the numerator is the number of years
          of service credited to the Participant for benefit accrual purposes
          under the Vastar Retirement Plan and the denominator of which is the
          total number of years of service credited to the Participant for
          benefit accrual purposes under the Retirement Plans.

     (c)  SURVIVOR BENEFIT

          (1) DEATH OF PARTICIPANT PRIOR TO COMMENCEMENT OF BENEFIT.

               (i) General Calculation. If a Participant who is entitled to
               receive a benefit under this Article dies prior to commencing
               receipt of the benefit, then the Participant's Beneficiary will
               be paid a monthly survivor benefit under this Article equal to a
               percentage, as described in the next paragraph of this
               Subsection, of the difference, if any, between (A) the monthly
               Pre-Retirement Annuity that would have been payable to the
               Participant's Beneficiary under the Retirement Plans if the
               calculation of the Pre-Retirement Annuity were not subject to
               limitations or reductions required under the Code or ERISA, and
               (B) the monthly Pre-Retirement Annuity payable to the
               Participant's Beneficiary under the Retirement Plans.

               (ii) Specific Survivor Benefit. The percentage of the difference
               in the monthly benefit calculation under Section 3.2(c)(1)(i)
               (which shall be the actual survivor benefit payable under this
               Article) shall be the percentage equivalent to a fraction of
               which the numerator is the number of years of service credited to
               the Participant for benefit accrual purposes under the Vastar
               Retirement Plan and the denominator of which is the total number
               of years of service credited to the Participant for benefit
               accrual purposes under the Retirement Plans.

          (2) DEATH OF PARTICIPANT AFTER COMMENCEMENT OF BENEFIT. If a
          Participant dies after commencing receipt of the benefit, then the
          Participant's Beneficiary will be paid a monthly survivor benefit, if
          applicable, pursuant to the Participant's form of allowance elected
          under the Retirement Plans and Article V of this Plan.

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                                 ARTICLE IV

                    SPECIAL SUPPLEMENTAL RETIREMENT BENEFITS

At its sole discretion the Compensation Committee of the Board of Directors of
Vastar Resources, Inc. may award a Special Supplemental Retirement Benefit to
any Employee in such amount, or to be computed on such basis, as it may
determine. Such awards may be granted for any reason deemed appropriate by the
Compensation Committee, including without limitation, recognition of all or any
part of the Employee's years of service with an organization or entity acquired
by, or merged into, Vastar Resources, Inc., any of its subsidiaries or
affiliates, or by any predecessor company of Vastar Resources, Inc. or any of
its subsidiaries or affiliates. In no event shall a Special Supplemental
Retirement Benefit be granted under the Plan to or on account of any Employee
who is not a member of a select group of management or other highly compensated
employees as defined from time to time by the Compensation Committee. A
certified copy of the resolutions granting a Special Supplemental Retirement
Benefit shall be furnished to the Administrator prior to the date any payment on
account thereof is to be made under the Plan.

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                                   ARTICLE V

                          FORM AND TIMING OF BENEFIT


5.1  BENEFITS PAYABLE UNDER ARTICLES II AND III

     (a) OPTIONAL FORMS OF BENEFIT. The Participant may elect to receive payment
     of his or her benefit under Articles II and III in any form available for
     payment of the normal retirement benefit under the Vastar Retirement Plan,
     provided that (1) the same form of payment must be elected under Articles
     II and III, and (2) if the Participant elects a form of annuity under
     Articles II and III and under the Retirement Plans, then he must elect the
     same form of annuity under this Plan and the Retirement Plans. Participant
     benefits payable under Articles II and III shall commence at the same time
     as the benefits of the Participant under the Retirement Plans commence.

     (b)  ELECTIONS

          (1) The Participant shall elect the form of payment of his or her
          benefit to be received under Articles II and III of this Plan within
          the time frame, and on the election form, prescribed by the
          Administrator and communicated to the Participant in advance of the
          date the Participant is eligible to commence benefit payments.

          (2) If the Participant fails to elect the form of benefit payment
          within the time frame designated by the Administrator, then upon
          retirement the Participant will receive (i) if the Participant is
          married at the time of retirement, an annuity payment in the form of a
          Fifty Percent Joint and Survivor Annuity, with the surviving spouse as
          the Beneficiary or (ii) if the Participant is single at the time of
          retirement, an annuity in the form of the Basic Allowance.

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          (3) If the Participant makes an election of the form of payment of his
          or her benefit within the time frame designated by the Administrator
          and subsequently wishes to change this election prior to commencement
          of the benefit or, in the case of an annuity form of payment under
          which payments have commenced, to receive the remaining monthly
          payments in a Lump Sum which is the Actuarial Equivalent of the
          remaining annuity installments, then he may request, by application to
          the Administrator, to change the form of payment previously elected,
          (i) without any reduction in, or imposition of any penalty on, the
          Participant's Account, provided that the Administrator determines that
          the Participant has experienced a Financial Hardship justifying the
          request for a change of election, or (ii) the Administrator, in its
          sole discretion, determines that it is appropriate to grant the
          Participant's request based on the interests of the Company or the
          grantor trust established under Section 8.2.

          (4) The Participant may elect the form of payment of the Survivor
          Benefit that will apply in the event of the Participant's death prior
          to commencement of his or her benefit, which shall be one of the
          optional forms available under the Vastar Retirement Plan, or an
          immediate Lump Sum payment on the death of the Participant. If the
          Participant fails to make the election, payment to the Beneficiary
          will be an annuity payable in the form prescribed by the Vastar
          Retirement Plan. However, the Beneficiary may request the
          Administrator to change the Participant's prior election provided that
          the Administrator makes a finding described under either Section
          5.1(b)(3)(i) or (ii). Benefits paid in one of the optional forms of
          payment available under the Vastar Retirement Plan to the Beneficiary
          shall commence on the earliest date the Participant would have become
          eligible to begin receiving a retirement allowance; provided, however,
          that the Beneficiary may elect to receive a Lump Sum, subject to the
          requirements described in Section 5.1(b)(3)(i) or (ii).

5.2  BENEFITS PAYABLE UNDER ARTICLE IV

          The form of payment of any benefit under Article IV, including any
     survivor benefit provisions, and the time for commencement of payment,
     shall be as determined by the Compensation Committee of the Board of
     Directors of Vastar Resources, Inc. and prescribed in the Committee's
     resolutions granting such benefit.

5.3  BENEFITS PAYABLE AFTER A CHANGE OF CONTROL

     (a) GENERAL. Notwithstanding anything to the contrary in any other Section 
     of this Plan, effective immediately upon a Change of Control, other than an
     ARCO Acquisition or an ARCO Takeover, the Administrator shall cause an 

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     amount equal to the Lump Sum payment for each Participant to be transferred
     from the Plan to the Vastar Resources, Inc. Executive Deferral Plan and
     credited to the Participant's account in the Executive Deferral Plan,
     provided, however, that if a Participant does not have an account in the
     Executive Deferral Plan, the Lump Sum payment applicable to such
     Participant's benefit under this Plan shall be immediately paid to the
     Participant in complete satisfaction of the Participant's rights hereunder.
     Thereafter, the benefits payable under this Plan shall be governed by the
     terms of the Executive Deferral Plan. However, with respect to (i) the
     remaining annuity payments to be received by any Participant or
     Beneficiary pursuant to this Plan whose annuity payments have commenced as
     of the date of the Change of Control and (ii) the benefit payable to any
     Participant who terminated his or her employment prior to a Change of
     Control (or a Beneficiary who became entitled to a benefit under this Plan
     as a result of a death of a Participant occurring prior to a Change of
     Control) which has not commenced as of the date of a Change of Control, the
     benefits payable to such persons shall continue as provided for in this
     Plan.

     (b) ARCO TAKEOVER. The Chief Financial Officer and the General Counsel of
     the Company may elect, by means of a written determination made in their
     sole discretion either prior to but not longer than 15 days after an ARCO
     Takeover to apply the provisions of Section 5.3(a) and Article IX as if a
     Change of Control (other than an ARCO Acquisition or an ARCO Takeover) had
     occurred on the date of such determination. In the absence of such a
     determination, the benefits payable to Participants shall continue as
     provided for in this Plan, as amended from time to time pursuant to 
     Article IX.

     (c) ARCO ACQUISITION. In the event of an ARCO Acquisition the benefits
     payable to Participants shall continue as provided for in this Plan, as
     amended from time to time pursuant to Article IX; provided, however, that
     in the event a Secondary Change of Control occurs, the provisions of
     Section 5.3(a) and Article IX shall apply as if the Secondary Change of
     Control were a Change of Control.

                                                                              16

 
                                  ARTICLE VI

                                ADMINISTRATION

6.1  RULES OF CONDUCT

          The Administrator shall adopt such rules for the conduct of its
     business and administration of this Plan as it considers desirable,
     provided they do not conflict with the provisions of this Plan.

6.2  LEGAL, ACCOUNTING, CLERICAL AND OTHER SERVICES

          The Administrator may authorize one or more of its members (if
     applicable) or any agent to act on its behalf and may contract for legal,
     accounting, clerical and other services to carry out this Plan. All
     expenses of the Administrator shall be paid by the Company or by the
     trustee of the grantor trust described in Section 8.2 (the "Trustee").

6.3  INTERPRETATION OF PROVISIONS

          The Administrator shall have the right to interpret the provisions of
     this Plan and to decide questions arising in its administration. The
     decisions and interpretations of the Administrator shall be final and
     binding on the Company, the Participants, the Trustee and all other
     persons.

6.4  RECORDS OF ADMINISTRATION

          The Administrator shall keep records reflecting the administration of
     this Plan which shall be subject to audit by the Company and the Trustee.

6.5  DENIAL OF CLAIM

          The Administrator shall provide adequate notice in writing to any
     Participant or Beneficiary whose claim for benefits under this Plan has
     been denied, setting forth the specific reasons for such denial. The
     Participant or Beneficiary will be given an opportunity for a full and fair
     review by the Administrator of the decision denying the claim. The
     Participant or Beneficiary shall be given 60 days from the date of the
     notice denying any such claim within which to request such review.

                                                                              17

 
6.6  LIABILITY OF COMMITTEE

          No member of the Administrator shall be liable for any action taken in
     good faith or for exercise of any power given the Administrator, or for the
     actions of other members, if any, of said Administrator.

                                                                              18

 
                                  ARTICLE VII

                   FACILITY OF PAYMENT AND LAPSE OF BENEFITS

7.1  PROVISIONS FOR INCAPACITY

          If the Administrator deems any person entitled to receive any payment
     under the provisions of this Plan incapable of receiving or disbursing the
     same by reason of minority, illness or infirmity, mental incompetency, or
     incapacity of any kind, the Administrator may, in its sole discretion, take
     any one or more of the following actions:

          (1) it may apply such payment directly for the comfort, support and
          maintenance of such person;
  
          (2) it may reimburse any person for any such support theretofore
          supplied to the person entitled to receive any such payment;

          (3) or it may pay such payment to any other person selected by the
          Administrator to disburse such payment for the comfort, support and
          maintenance of the person entitled thereto, including, without
          limitation, to any relative who has undertaken, wholly or partially,
          the expense of such person's comfort, care and maintenance, or any
          institution in whose care or custody the person entitled to the
          payment may be. The Administrator may, in its sole discretion, deposit
          any payment due to a minor to the minor's credit in any savings or
          commercial bank of the Administrator's choice.

7.2  PAYMENTS OF DEPOSITS

          Payments or deposits made pursuant to any provisions of this Article
     shall be a complete discharge, to the extent thereof, of all liability
     under the provisions of this Plan, or otherwise, of the Administrator, the
     Company and this Supplementary Executive Retirement Plan, and the receipt
     by the person or persons receiving any such payment, distribution or
     deposit shall be a complete acquittance therefore, and there shall be no
     liability to see to the application of any payments, distributions or
     deposits so made.

                                                                              19

 
                                 ARTICLE VIII

                                 MISCELLANEOUS

8.1  UNFUNDED BENEFIT PLAN

       (a) Benefits under Articles II and IV of this Supplementary Executive
     Retirement Plan are intended to constitute a plan which is unfunded and
     maintained primarily for the purpose of providing deferred compensation in
     the form of additional retirement benefits to a select group of management
     or highly compensated employees as defined in (S)201(a)(2), (S)301(a)(3)
     and (S)401(a)(1) of ERISA.

       (b) Benefits under Article III of this Plan are intended to constitute an
     unfunded "Excess Benefit Plan" within the meaning of (S)3(36) of ERISA.

8.2  GRANTOR TRUST

          Although the Company is responsible for the payment of all benefits
     under the Plan, the Company may, in its discretion, contribute funds to a
     grantor trust for the purpose, as it deems appropriate, of paying benefits
     under this Plan. Such trust may be irrevocable, but assets of trust shall
     be subject to the claims of creditors of Vastar Resources, Inc. or its
     successors to the extent provided in the terms governing such trust. Upon
     the earlier to occur of a Change of Control or an Anticipatory Change of
     Control, the Company shall be required to make certain contributions to a
     grantor trust pursuant to the terms of that certain trust agreement between
     the Company or its successors and Wachovia Bank, N.A., as trustee, dated as
     of March 10, 1999, or any successor trust agreement including any
     amendments or supplements thereto or if such trust agreement has not been
     executed such grantor trust of the Company designated by the Senior Vice
     President and Chief Financial Officer and the General Counsel of the
     Company. To the extent any benefits provided under the Plan are actually
     paid from the trust, the Company shall have no further obligation with
     respect thereto but to the extent not so paid, such benefits shall remain
     the obligation of, and shall be paid by, the Company. The Participants
     shall have the status of unsecured creditors insofar as their legal claim
     for benefits under the Plan and the Participants shall have no security
     interest in any assets of the grantor trust.

                                                                              20

 
8.3  PAYMENTS AND BENEFITS NOT ASSIGNABLE

          Payments to and benefits under this Plan are not assignable,
     transferable or subject to alienation since they are primarily for the
     support and maintenance of the Participants and their joint annuitants or
     Beneficiaries after retirement. Similarly, subject to Section 8.2, such
     payments shall not be subject to attachments by creditors of, or through
     legal process against, the Company, the Administrator or any Participant.

8.4  NO RIGHT OF EMPLOYMENT

          The provisions of this Plan shall not give a Participant the right to
     be retained in the service of the Company nor shall this Plan or any action
     taken under the Plan be construed as a contract of employment.

8.5  ADJUSTMENTS

          At the request of the Company, the Administrator may, with respect to
     a Participant, adjust such Participant's benefit under this Plan or make
     such other adjustments with respect to such Participant as are required to
     correct administrative errors or provide uniform treatment of Participants
     in a manner consistent with the intent and purpose of this Plan.

8.6  OBLIGATION TO COMPANY

          If a Participant becomes entitled to a distribution of benefits under
     the Plan, and if at such time the Participant has outstanding any debt,
     obligation, or other liability representing an amount owing to the Company,
     or any benefit plan maintained by the Company, then, prior to the earlier
     to occur of a Change of Control or an Anticipatory Change of Control, the
     Company may offset such amount owed to it or such benefit plan against the
     amount of benefits otherwise distributable. Such determination shall be
     made by the Administrator.

8.7  PROTECTIVE PROVISIONS

     (a) Each Participant shall reasonably cooperate with the Administrator by
     furnishing information and taking such other actions as may be requested by
     the Company in order to facilitate the payment of benefits hereunder.

                                                                              21

 
     (b) The Administrator may withhold payment under the Plan until a
     Participant provides reasonable cooperation with information or other
     requests of the Administrator. Prior to the earlier to occur of an
     Anticipatory Change of Control or a Change of Control, in the Company's
     sole discretion, benefits may be payable in an amount reduced to compensate
     the Company for any loss, cost, damage or expense suffered or incurred by
     the Company as a result in any way of any action, misstatement or
     nondisclosure by the Participant.

8.8  GENDER, SINGULAR AND PLURAL

          All pronouns and any variations thereof shall be deemed to refer to
     the masculine, feminine, or neuter, as the identity of the person or
     persons may require. As the context may require, the singular may be read
     as the plural and the plural as the singular.

8.9  LAW GOVERNING

          This Plan shall be construed, regulated and administered under the
     laws of the State of Delaware.

8.10  VALIDITY

          In the event any provision of this Plan is held invalid, void, or
     unenforceable, the same shall not affect, in any respect whatsoever, the
     validity of any other provision of this Plan.

8.11  NOTICE

          Any notice or filing required or permitted to be given to the
     Administrator under the Plan shall be sufficient if in writing and hand
     delivered, or sent by registered or certified mail, to the principal office
     of the Administrator, directed to the attention of the Manager, Vastar
     Benefit Plans Compliance. Such notice shall be deemed given as of the date
     of delivery or, if delivery is made by mail, as of the date shown on the
     postmark on the receipt for registration or certification.

8.12  SUCCESSORS AND ASSIGNS

          This Plan shall be binding upon the Company and its successors and
     assigns.

                                                                              22

 
8.13  TAX WITHHOLDING

          The Company shall have the right to withhold from Salary (or otherwise
      to cause the Participant or the executor or administrator of his or her
      estate, or his or her Beneficiary to make payment to the Company of) any
      federal, state, local or foreign taxes required to be withheld with
      respect to any payments made pursuant to this Plan. The Administrator
      shall withhold from Plan distributions such amount as shall be necessary
      to satisfy applicable federal, state and local tax withholding
      requirements with respect to such distributions.

                                                                              23

 
                                  ARTICLE IX.

                           AMENDMENT AND TERMINATION

Section 9.1  AMENDMENT OF PLAN

          Prior to the earlier to occur of an Anticipatory Change of Control or 
a Change of Control, and subject to Section 9.3 hereof, this Plan may be amended
from time to time by the Board of Directors of Vastar or its designee. 
Notwithstanding the above, after the earlier to occur of an Anticipatory Change
Termination (as defined in Section 1.3(b)) or the expiration of the Transition 
Window, this Plan may again be amended, subject to Section 9.3, from time to 
time by the Board of Directors of Vastar or its designee.

Section 9.2  TERMINATION

          Vastar intends to continue this Plan indefinitely, but reserves the 
right, subject to section 9.3, to terminate it at any time prior to an 
Anticipatory Change of Control or a Change of Control by action of its Board of 
Directors or its designee. Notwithstanding the above, after the earlier to occur
of an Anticipatory Change Termination (as defined in Section 1.3(b)) or the 
expiration of the Transition Window, this Plan may again be amended, subject to 
Section 9.3, from time to time by the Board of Directors of Vastar or its 
designee.

Section 9.3  EFFECT OF AMENDMENT OR TERMINATION

          No amendment or termination of this Plan may adversely affect the
benefit payable or rights afforded to any Participant as of the effective date
of the amendment or termination, or any Beneficiary who, as of such date, was
then eligible to receive a benefit under this Plan.

Section 9.4  SPECIAL AMENDMENTS APPROVED BY PARTICIPANTS

          Notwithstanding anything to the contrary in this Article IX, after the
earlier to occur of an Anticipatory Change of Control or a Change of Control, 
this Plan may be amended, subject to Section 9.3, by a vote of 80% or more of 
the votes cast by the Participants with regard to such amendment. Each 
Participant shall be entitled to a number of votes equal to the number of 
dollars credited to his or her Account as of the last day of the month 
immediately preceding the vote. In the event any material amendment is approved 
as provided above, the Participants who vote against the amendment shall be 
given an option to receive a lump sum distribution of their Account as soon as 
practicable after the effective date of the amendment.

                                                                              24

 
Executed as of the 24th day of March, 1999.


ATTEST                        VASTAR RESOURCES, INC.



By /s/ Jonathan D. Edelfelt   By /s/ Jeffrey M. Bender
  -------------------------     -------------------------------
  Jonathan D. Edelfelt          Jeffrey M. Bender
  Associate Secretary           Vice President, Human Resources

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