EXHIBIT 10.20
Amendment
To
Apache Corporation Money Purchase Retirement Plan
Apache Corporation ("Apache") maintains the Apache Corporation Money
Purchase Retirement Plan (the "Plan"). In section 9.4 of the Plan, Apache
reserved the right to amend the Plan from time to time. Apache hereby exercises
such right as follows, by replacing the chart at the end of Appendix C with the
following chart, effective as of January 1, 2003.
<Table>
<Caption>
Former Employer New Employees
--------------- -------------
Crescendo Resources, L.P. ("Crescendo") All individuals hired from April 30, 2000 through
June 1, 2000 from Crescendo and related
companies in connection with an April 30, 2000
asset acquisition from Crescendo.
Collins & Ware ("C&W") and Longhorn All individuals hired from C&W, Longhorn, and
Disposal, Inc. ("Longhorn") related companies in connection with a May 23,
2000 asset acquisition from C&W and Longhorn.
Occidental Petroleum Corporation ("Oxy") All individuals hired from Oxy and related
companies in connection with an August 2000
asset acquisition from an Oxy subsidiary.
Private company ("Private") All individuals hired in January 2003 from Private
and related companies in connection with an asset
acquisition of certain property in Louisiana
effective as of December 1, 2002.
</Table>
EXECUTED this 27th day of January 2003.
APACHE CORPORATION
By: /s/ Jeffrey M. Bender
----------------------------------
Name: Jeffrey M. Bender
Title: Vice President, Human Resources
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