Exhibit 10.20

Non-Qualified Retirement/Savings Plan of Apache Corporation

Apache Corporation (“Apache”) sponsors the Non-Qualified Retirement/Savings Plan
of Apache Corporation (the “Plan”). In section 8.02 of the Plan, Apache reserved
the right to amend the Plan from time to time. Apache hereby exercises that
right, as follows, effective as of January 1, 2012.

1. Section 1.10(b)(xii) of the Plan shall be replaced in its entirety with the
following.

 

  (xii) payments from any benefit plan, such as any stock appreciation rights or
payments from a Share Appreciation Plan, any payment from the Deferred Delivery
Plan or the Executive Restricted Stock Plan, and payments pursuant to grants
made under the Omnibus Equity Compensation Plan of 2007 or Omnibus Equity
Compensation Plan of 2011, and

2. Section 3.01(b) of the Plan shall be replaced in its entirety with the
following.

 

  (a) Maximum and Minimum Deferrals. A Participant may elect to defer up to 50%
of his Compensation (other than a bonus described in section 1.10(a)(iii)) and
up to 75% of a bonus described in section 1.10(a)(iii). The minimum deferral
that a Participant may elect for both this Plan and the Savings Plan combined is
8% of his Compensation.

3. Section 3.01(d) of the Plan shall be replaced in its entirety with the
following.

 

  (d) Procedures for Making Elections. The Committee has complete discretion to
establish procedures for the completion of Enrollment Agreements, including the
acceptable forms and formats of the deferral election (for example, written or
electronic, as a whole percentage of Compensation or specific dollar amount, and
the manner in which the Enrollment Agreement coordinates with the Savings Plan).
The Committee has complete discretion to establish the enrollment periods during
which Participants may make Enrollment Agreements, within the bounds described
in subsections (a) and (c). The Committee may establish different enrollment
periods for different types of Compensation or different groups of Participants.
The Committee may specify any default choices that will apply unless the
Participant affirmatively elects otherwise. For example, the Committee could
decide that the failure to complete a new Enrollment Agreement means that
(i) the prior Plan Year’s Enrollment Agreement for that type of Compensation
will be continued for another year, or (ii) no Participant Deferrals will be
made, or (iii) the Participant will defer 8% of his Compensation in excess of
the limit on compensation that can be taken into account for benefit-calculation
purposes in the Savings Plan and the Retirement Plan pursuant to Code
§401(a)(17).

4. The first sentence of Section 3.01(f) of the Plan (regarding that section’s
effective date) shall be eliminated.

5. Section 3.02(a)(i) of the Plan shall be replaced in its entirety with the
following.

 

  (i) Basic Match. The “total match” for the Plan Year is equal to the
Participant’s “total deferrals” for the Plan Year, up to a maximum total match
for the Plan Year of 8% of the Participant’s Compensation for the Plan Year,
except that the match in this Plan is $0 if the Participant has not made the
maximum contributions to the Savings Plan that are excludable from his gross
income pursuant to Code §402(g).

6. Section 3.02(e) of the Plan shall be replaced in its entirety with the
following.

 

  (e) Retirement-6. In order to receive an allocation of the retirement-6
contribution, an employee must be eligible to participate in the Plan on the
last business day of the Plan Year.

 

  (i) Basic Retirement-6 Contribution. The retirement-6 contribution for the
Plan Year is equal to 6% of the Participant’s Compensation for the Plan Year
that is in excess of the limit on compensation that may be taken into account in
the Retirement Plan pursuant to Code §401(a)(17).

 

Prepared December 17, 2011

 

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  (ii) Potential Additional Retirement-6 Contribution. If a Participant’s
Company Mandatory Contribution in the Retirement Plan is reduced to comply with
any requirement of federal law, then the Participant’s retirement-6 contribution
for this Plan calculated under paragraph (i) will be increased by the amount of
the reduction in the Company Mandatory Contribution in the Retirement Plan. For
example, a Participant will receive an extra $2,000 retirement-6 contribution in
this Plan for 2012 if he is age 49 or older on January 1, 2012, has Compensation
over $250,000, makes the maximum contribution to the Savings Plan (the $17,000
basic 401(k) contribution and the $5,500 catch-up contribution), receives a
$20,000 match in the Savings Plan (8% of $250,000), and has his Company
Mandatory Contribution in the Retirement Plan reduced from $15,000 (6% of
$250,000) to $13,000 because of the limitations of Code §415(c).

7. Section 5.02(b) of the Plan shall be replaced its entirety with the
following.

 

  (b) Vesting. If a Participant becomes eligible to again make Participant
Deferrals more than five years after Separating from Service, (i) the Plan will
establish a new Account for the benefits he accrues during his second episode of
participation; (ii) his years of completed service for his new Account will
include only his service from his second episode; and (iii) his new service will
not increase the vesting of any benefits from his first episode of
participation. If a Participant becomes eligible to again make Participant
Deferrals less than five years after Separating from Service (or if he never
Separated from Service), the Participant’s years of completed service for his
benefits from his second episode of participation will include his service from
both episodes of employment.

8. Section 5.04(a) of the Plan shall be amended by replacing both occurrences of
the date “January 1, 2009” with the date “January 1, 2012.”

9. Section 5.04(c)(i) of the Plan shall be replaced in its entirety with the
following.

 

  (i) Matched and Unmatched Participant Deferrals. Because different payout
alternatives are available for matched and unmatched Participant Deferrals, the
Plan will separately account for matched and unmatched Participant Deferrals.
Each Plan Year’s unmatched Participant Deferrals, if any, are equal to the
amount by which the sum of the Participant Deferrals to this Plan for the Plan
Year and the Before-Tax Contributions to the Savings Plan for the Plan Year are
greater than 8% of the Participant’s Compensation for the Plan Year. The
Committee has full discretion in determining an appropriate and administratively
feasible method for differentiating between matched and unmatched Participant
Deferrals. The Committee may wait until the end of the Plan Year to make this
determination, and may attribute the investment earnings or losses on the
Participant Deferrals to the matched Participant Deferrals, to the unmatched
Participant Deferrals, or partly to each.

10. The first paragraph of Section 5.04(c)(iii) of the Plan shall be replaced in
its entirety with the following.

 

  (i) Payout Elections for Unmatched Participant Deferrals. A Participant shall
make a separate payout election for the next year’s unmatched Participant
Deferrals. The payout election must be made no later than June 30 (or such
earlier date established by the Committee) of the year preceding the year in
which the unmatched Participant Deferral occurs. Newly eligible Participants
must complete a payout election at the same time as their initial Enrollment
Agreement. The Participant may choose from among the following payout
alternatives for the subaccount containing that Plan Year’s unmatched
Participant Deferrals.

11. Section 5.06(b)(ii) of the Plan shall be replaced its entirety with the
following.

 

  (ii) Payout upon a Change of Control. This paragraph applies only to benefits
accrued after December 31, 2010. A Participant may elect to have all his vested
benefits accrued after December 31, 2010 paid to him in a single payment on the
date of the Change of Control or as soon as administratively practicable
thereafter; to the extent the Participant does not elect to

 

Prepared December 17, 2011

 

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  receive payment upon the Change of Control, his benefits shall be paid
pursuant to whichever of sections 5.04, 5.05, 5.06(b)(i), 5.07, or 5.08 applies.
A new Participant’s election under this paragraph must be made no later than the
deadline for the Participant’s initial payout election pursuant to section
5.04(b)(i) (that is, within 30 days of becoming eligible to participate in the
Plan) or such earlier date as the Committee may establish.

12. Section 6.01(a) of the Plan shall be replaced its entirety with the
following.

 

  (a) Current. The Committee is currently comprised of the members of the
Retirement Plan Advisory Committee.

13. Section 9.04(b) of the Plan shall be replaced its entirety with the
following.

 

  (b) Representatives. A claimant may appoint a representative to act on his
behalf. The Plan will only recognize a representative if the Plan has received a
written authorization signed by the claimant and on a form prescribed by the
Committee, with the following exceptions. The Plan will recognize a claimant’s
legal representative, once the Plan is provided with documentation of such
representation. If the claimant is a minor child, the Plan will recognize the
claimant’s parent or guardian as the claimant’s representative. Once an
authorized representative is appointed, the Plan will direct all information and
notification regarding the claim to the authorized representative and the
claimant will not be copied on any notifications regarding decisions, unless the
claimant provides specific written direction otherwise.

EXECUTED this 19th day of December, 2011.

 

APACHE CORPORATION By:   /s/ Margery M. Harris   Margery Harris   Senior Vice
President, Human Resources

 

Prepared December 17, 2011

 

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