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                                                                     EXHIBIT 8.1

                     [WOODWARD, HALL & PRIMM LETTERHEAD]




                               November 21, 1997


Apache Corporation
2000 Post Oak Boulevard
Suite 100
Houston, Texas 77056-4400

         Re:  Registration Statement on Form S-3

Ladies and Gentlemen:

         We have acted as counsel for Apache Corporation, a Delaware
corporation (the "Company"), and Apache Finance Pty Ltd, a proprietary company
with limited liability organized under the laws of the Australian Capital
Territory, Australia (the "Issuer"), in connection with the Company's and the
Issuer's Registration Statement on Form S-3 (the "Registration Statement")
relating to the registration under the Securities Act of 1933, as amended, of
up to an aggregate $300,000,000 principal amount of the Issuer's debt securities
(the "Debt Securities") and the guarantees (the "Guarantees") of the Debt
Securities by the Company. The Debt Securities are to be issued from time to
time in one or more series pursuant to an Indenture among the Issuer, the
Company (as Guarantor) and The Chase Manhattan Bank, as trustee. The terms of
the Debt Securities and Guarantees, which are set forth in the Registration
Statement, are incorporated herein by reference.

         Based upon the terms of the Debt Securities and Guarantees, as set
forth in the Registration Statement, we hereby confirm that the discussion set
forth in the Registration Statement under the caption "Certain Tax
Considerations - United States Federal Income Tax Considerations," except as
otherwise stated therein, constitutes our opinion as to the material United
States federal income tax considerations of the acquisition, holding and
disposition of the Debt Securities.

         The opinions expressed in the preceding paragraph are limited to the
tax matters specifically discussed under the caption "Certain Tax
Considerations - United States Federal Income Tax Considerations" in the
Registration Statement, and we have not been asked to address nor have we
addressed, any other tax considerations relating to the Debt Securities,
including the discussion set
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forth in the Registration Statement under the caption "Certain Tax
Considerations - Australian Tax Considerations," for which we understand you
are relying on the opinion of Arthur Robinson & Hedderwicks.

         Pursuant to the provisions of Rule 436(a) promulgated by the
Securities and Exchange Commission under the 1933 Act, we hereby consent to the
filing of this letter as an exhibit to the Registration Statement and to the
reference to us under the caption "Certain Tax Considerations - United States
Federal Income Tax Considerations" and "Legal Matters" in the related
prospectus included therein.


                                        Very truly yours,

                                        /s/ WOODARD, HALL & PRIMM, P.C.