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                                                                     EXHIBIT 4.4

                      SECOND AMENDMENT TO CREDIT AGREEMENT

        This Second Amendment to Credit Agreement (this "Second Amendment") is
effective as of June 30, 2003 (the "Effective Date"), by and among WHITING
PETROLEUM CORPORATION, a Delaware corporation ("Borrower"), BANK ONE, NA, a
national banking association, as Administrative Agent ("Administrative Agent"),
and each of the financial institutions a party hereto as Banks (hereinafter
collectively referred to as "Executing Banks," and individually, an "Executing
Bank").

                              W I T N E S S E T H :

        WHEREAS, Borrower, Administrative Agent and Banks are parties to that
certain Credit Agreement dated as of December 20, 2002, as amended by that
certain First Amendment to Credit Agreement dated as of January 7, 2003 (the
"Credit Agreement") (unless otherwise defined herein, all terms used herein with
their initial letter capitalized shall have the meaning given such terms in the
Credit Agreement); and

        WHEREAS, Borrower has advised Banks that AER intends to dispose of its
stock in Borrower in transactions which may include (a) a sale of the shares of
common stock of Borrower in a private transaction to the Designated Shareholders
(as hereinafter defined), and/or (b) a sale of the shares of common stock of
Borrower to the public pursuant to an initial public offering under the Exchange
Act; and

        WHEREAS, the transactions described in the preceding paragraph are
prohibited by certain provisions of the Credit Agreement as in effect on the
date hereof; and

        WHEREAS, Borrower has requested that the Credit Agreement be amended in
certain respects to permit such transactions; and

        WHEREAS, subject to and upon the terms and conditions set forth herein,
Executing Banks have agreed to Borrower's request.

        NOW THEREFORE, for and in consideration of the mutual covenants and
agreements herein contained and other good and valuable consideration, the
receipt and sufficiency of which are hereby acknowledged and confessed,
Borrower, Administrative Agent and each Executing Bank hereby agree as follows:

        SECTION 1. Amendments. In reliance on the representations, warranties,
covenants and agreements contained in this Second Amendment, and subject to the
satisfaction of each condition precedent set forth in Section 2 hereof, the
Credit Agreement is hereby amended effective as of the Effective Date in the
manner provided in this Section 1.

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        1.1.    Amendment to Definitions. The definitions of "Change of
Control," "Loan Papers" and "Restricted Payment" contained in Section 1.1 of the
Credit Agreement shall be amended to read in full as follows:

                "Change of Control" means that, for any reason (a) at any time
        prior to the completion of a Qualified Public Offering or the Equity
        Investment, Borrower shall cease to be a wholly-owned direct or indirect
        Subsidiary of Alliant, (b) at any time prior to the completion of a
        Qualified Public Offering but after the completion of the Equity
        Investment, Alliant shall cease to hold, directly or indirectly, at
        least fifty one percent (51%) of the total voting power of all classes
        of capital stock then outstanding of Borrower entitled (without regard
        to the occurrence of any contingency) to vote in elections of directors
        of Borrower, (c) at any time prior to the completion of the Equity
        Investment but after the completion of a Qualified Public Offering, any
        Person or group (as defined in Section 13(d)(3) or 14(d)(2) of the
        Exchange Act) other than Alliant shall become (i) the direct or indirect
        beneficial owner (as defined in Section 13(d)(3) of the Exchange Act) of
        greater than forty-nine percent (49%) of the total voting power of all
        classes of capital stock then outstanding of Borrower entitled (without
        regard to the occurrence of any contingency) to vote in elections of
        directors of Borrower, and (ii) the largest shareholder of the total
        voting power of all classes of capital stock then outstanding of
        Borrower entitled (without regard to the occurrence of any contingency)
        to vote in elections of directors of Borrower, and (d) at any time after
        the completion of a Qualified Public Offering and the Equity Investment,
        any Person or group (as defined in Section 13(d)(3) or 14(d)(2) of the
        Exchange Act) other than the Designated Shareholders shall become (i)
        the direct or indirect beneficial owner (as defined in Section 13(d)(3)
        of the Exchange Act) of greater than forty-nine percent (49%) of the
        total voting power of all classes of capital stock then outstanding of
        Borrower entitled (without regard to the occurrence of any contingency)
        to vote in elections of directors of Borrower, and (ii) the largest
        shareholder of the total voting power of all classes of capital stock
        then outstanding of Borrower entitled (without regard to the occurrence
        of any contingency) to vote in elections of directors of Borrower.

                "Loan Papers" means this Agreement, the First Amendment, the
        Second Amendment, the Notes, each Facility Guaranty which may now or
        hereafter be executed, each Borrower Pledge Agreement which may now or
        hereafter be executed, each Subsidiary Pledge Agreement which may now or
        hereafter be executed, all Mortgages now or at any time hereafter
        delivered pursuant to Section 5.1, all Letters of Credit, and all other
        certificates, documents or instruments delivered in connection with this
        Agreement, as the foregoing may be amended from time to time.

                "Restricted Payment" means, with respect to any Person, (a) any
        Distribution by such Person, (b) any capital contribution, loan or
        advance by any Credit Party to any Unrestricted Subsidiary, (c) the
        issuance of a Guarantee by any Credit Party with respect to any Debt or
        other obligation of Parent, Alliant, AER or any Unrestricted Subsidiary,
        or (d) the retirement, redemption, defeasance, repurchase or prepayment
        prior to scheduled maturity by such Person or any Affiliate of such
        Person of any Debt of such Person.

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        1.2.    Additional Definitions. Section 1.1 of the Credit Agreement
shall be amended to add the following definitions to such Section:

                "Designated Shareholders" means shareholders of Borrower, other
        than Alliant, which are designated by Borrower, and approved by Required
        Banks, as "Designated Shareholders" pursuant to a written designation
        and notice executed and delivered by Borrower to, and acknowledged by,
        Administrative Agent (on behalf of Required Banks).

                "Equity Investment" means the purchase by the Designated
        Shareholders of the common stock of Borrower, with the proceeds of such
        purchase being distributed to Alliant or Borrower to be applied, in the
        case of proceeds distributed to Borrower, towards the purchase of oil
        and gas properties.

                "Qualified Public Offering" means the first underwritten public
        offering pursuant to an effective registration statement under the
        Exchange Act covering the offering and sale of the common stock of
        Borrower.

                "Second Amendment" means that certain Second Amendment to Credit
        Agreement dated as of June 30, 2003, among Borrower, Administrative
        Agent and Banks.

        1.3.    Deletion of Definitions. Section 1.1 of the Credit Agreement
shall be amended to delete the definitions of "Consolidated Senior Debt,"
"Subordinate Debt," "Subordinate Loan Documents" and "Subordinate Note" from
such Section.

        1.4.    Amendment to Organizational Representation. Section 7.13 of the
Credit Agreement shall be amended to read in full as follows:

                "Section 7.13 Organizational Structure; Nature of Business. As
        of the Closing Date and the Effective Date (as defined therein) of the
        Second Amendment, Borrower has no direct, wholly-owned Subsidiaries,
        other than Whiting-Golden Gas, WOK and Whiting Programs. Whiting
        Programs is the general partner of various partnerships that own oil and
        gas properties that are not Borrowing Base Properties. Borrower also
        owns, directly and partially indirectly through Whiting Programs, one
        hundred percent (100%) of the Equity in Whiting Institutional, which has
        assets of not greater than $2,000,000, and which assets are not included
        in the Borrowing Base. Borrower is engaged only in the business of
        acquiring, exploring, developing and operating Mineral Interests and the
        production, processing and marketing of Hydrocarbons therefrom. Schedule
        7.13 attached hereto accurately reflects (i) the jurisdiction of
        incorporation or organization of each Credit Party, (ii) each
        jurisdiction in which each Credit Party is qualified to transact
        business as a foreign corporation, foreign partnership or foreign
        limited liability company, (iii) the authorized, issued and outstanding
        Equity of each Credit Party (and the record and beneficial owners of
        such Equity interests), and (iv) all outstanding warrants, options,
        subscription rights, convertible securities or other rights to purchase
        Equity of each Credit Party. Promptly following the completion of the
        Equity Investment and/or a Qualified Public Offering,

                                        3

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        Borrower shall prepare and deliver to Administrative Agent, as
        applicable, an amended Schedule 7.13 reflecting changes resulting from
        the consummation of such transactions."

        1.5.    Subordinate Loan Representation. Section 7.21 of the Credit
Agreement shall be amended to read in full as follows:

                "Section 7.21 [Intentionally Deleted]."

        1.6.    Amendment to Information Covenant. Section 8.1(d) of the Credit
Agreement shall be amended to read in full as follows:

                "(d)    promptly upon (i) the filing thereof, copies of all
        final registration statements, post-effective amendments thereto and
        annual, quarterly or special reports which any Credit Party shall have
        filed with the Securities and Exchange Commission; provided, that
        Borrower must deliver, or cause to be delivered, any annual reports
        which any Credit Party shall have filed with the Securities and Exchange
        Commission, within ninety (90) days after the end of each Fiscal Year of
        such Credit Party, and any quarterly reports which any Credit Party
        shall have filed with the Securities and Exchange Commission, within
        forty-five (45) days after the end of each of the first three (3) Fiscal
        Quarters of each Fiscal Year of such Credit Party, and (ii) the mailing
        thereof to the stockholders of any Credit Party generally, copies of all
        financial statements, reports and proxy statements so mailed;".

        1.7.    Amendment to Debt Covenant. Section 9.1 of the Credit Agreement
shall be amended to read in full as follows:

                "Section 9.1 Incurrence of Debt. Borrower will not, nor will
        Borrower permit any other Credit Party to, incur, become or remain
        liable for any Debt other than (a) the Obligations, and (b) other
        unsecured Debt in an aggregate amount outstanding at any time not to
        exceed $5,000,000."

        1.8.    Amendment to Asset Disposition Covenant. The last sentence of
Section 9.5 of the Credit Agreement shall be amended to read in full as follows:

                "Except in connection with the Equity Investment or a Qualified
        Public Offering, in no event will Borrower sell, transfer or dispose of
        any Equity in any Subsidiary nor will any Credit Party issue or sell any
        Equity or any option, warrant or other right to acquire such Equity or
        security convertible into such Equity to any Person other than the
        Credit Party which is the direct parent of such issuer on the Closing
        Date."

        1.9.    Amendment to Organizational Documents Covenant. Section 9.6 of
the Credit Agreement shall be amended to read in full as follows:

                "Section 9.6 Amendments to Organizational Documents; Other
        Material Agreements. Borrower will not, nor will Borrower permit any
        other Credit Party to, enter into or permit any modification or
        amendment of, or waive any material right or obligation of any Person
        under, its certificate or articles of incorporation, bylaws, partnership
        agreement, regulations or other organizational documents other than

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        amendments, modifications and waivers (a) in connection with the Equity
        Investment or a Qualified Public Offering, or (b) which will not,
        individually or in the aggregate, have a Material Adverse Effect."

        1.10.   Deletion of Subordinate Debt Covenant. Section 9.14 of the
Credit Agreement shall be amended to read in full as follows:

                "Section 9.14 [Intentionally Deleted]."

        1.11.   Amendment to Financial Covenants. Section 10.2 and Section 10.3
of the Credit Agreement shall be amended to read in full as follows:

                "Section 10.2 Consolidated Total Debt to Annualized Consolidated
        EBITDAX. As of the end of any Fiscal Quarter, commencing with the Fiscal
        Quarter ending December 31, 2002, Borrower will not permit its ratio of
        Consolidated Total Debt to Annualized Consolidated EBITDAX to be greater
        than 3.0 to 1.0.

                Section 10.3 [Intentionally Deleted]."

        1.12.   Amendments to Events of Default. Subsections (m) and (n) of
Section 11.1 of the Credit Agreement shall be amended to read in full as
follows:

                "(m) a default or event of default shall occur under any Hedge
        Agreement under which the liability to Borrower could reasonably be
        expected to exceed $1,000,000, and any grace period applicable thereto
        shall have lapsed without cure or waiver of such default or event of
        default; or

                (n) [intentionally deleted];".

        SECTION 2. Conditions Precedent. The effectiveness of the amendments to
the Credit Agreement contained in Section 1 hereof is subject to the
satisfaction, on or prior to the Effective Date, of each condition precedent set
forth in this Section 2:

        2.1.    Amendment Fee. Upon execution of this Second Amendment by
Required Banks, Borrower shall pay to Administrative Agent, for the benefit of
Executing Banks, a fee in the amount of $5,000 for each Executing Bank. Such
$5,000 fee shall be distributed by Administrative Agent to each Executing Bank
provided that such Executing Bank executes and delivers this Second Amendment on
or before June 30, 2003.

        2.2.    Fees and Expenses. Borrower shall have paid all fees and
expenses incurred by Administrative Agent in connection with the preparation,
negotiation and execution of this Second Amendment, including, without
limitation, all fees and expenses of Vinson & Elkins L.L.P., counsel to
Administrative Agent.

        2.3.    No Defaults. No Default or Event of Default shall exist.

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        SECTION 3. Representations and Warranties of Borrower. To induce
Executing Banks and Administrative Agent to enter into this Second Amendment,
Borrower hereby represents and warrants to Banks and Administrative Agent as
follows:

        3.1.    Due Authorization; No Conflict. The execution, delivery and
performance by Borrower of this Second Amendment are within Borrower's corporate
powers, have been duly authorized by all necessary action, require no action by
or in respect of, or filing with, any governmental body, agency or official and
do not violate or constitute a default under any provision of applicable law or
any Material Agreement binding upon Borrower or result in the creation or
imposition of any Lien upon any of the assets of Borrower except Permitted
Encumbrances.

        3.2.    Validity and Enforceability. This Second Amendment constitutes
the valid and binding obligation of Borrower enforceable in accordance with its
terms, except as (i) the enforceability thereof may be limited by bankruptcy,
insolvency or similar laws affecting creditor's rights generally, and (ii) the
availability of equitable remedies may be limited by equitable principles of
general application.

        3.3.    Accuracy of Representations and Warranties. Each representation
and warranty of each Credit Party contained in the Loan Papers is true and
correct in all material respects as of the Effective Date (except to the extent
such representations and warranties are expressly made as of a particular date,
in which event such representations and warranties were true and correct as of
such date).

        3.4.    Absence of Defaults. No Default or Event of Default has occurred
which is continuing.

        3.5.    No Defense. Borrower has no defense to payment of, or any
counterclaim or rights of set-off with respect to, all or any portion of the
Obligations.

        SECTION 4. Miscellaneous.

        4.1.    Reaffirmation of Loan Papers. Any and all of the terms and
provisions of the Credit Agreement and the Loan Papers shall, except as amended
and modified hereby, remain in full force and effect. The amendments
contemplated hereby shall not limit or impair any Liens securing the
Obligations, each of which are hereby ratified, affirmed and extended to secure
the Obligations.

        4.2.    Parties in Interest. All of the terms and provisions of this
Second Amendment shall bind and inure to the benefit of the parties hereto and
their respective successors and assigns.

        4.3.    Legal Expenses. Borrower hereby agrees to pay on demand all
reasonable fees and expenses of counsel to Administrative Agent incurred by
Administrative Agent in connection with the preparation, negotiation and
execution of this Second Amendment.

        4.4.    Counterparts. This Second Amendment may be executed in
counterparts, and all parties need not execute the same counterpart; however, no
party shall be bound by this

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Second Amendment until Borrower and Required Banks have executed a counterpart.
Facsimiles shall be effective as originals.

        4.5.    Complete Agreement. THIS SECOND AMENDMENT, THE CREDIT AGREEMENT
AND THE OTHER LOAN PAPERS REPRESENT THE FINAL AGREEMENT AMONG THE PARTIES AND
MAY NOT BE CONTRADICTED BY EVIDENCE OF PRIOR, CONTEMPORANEOUS OR ORAL AGREEMENTS
OF THE PARTIES. THERE ARE NO UNWRITTEN ORAL AGREEMENTS BETWEEN OR AMONG THE
PARTIES.

        4.6.    Headings. The headings, captions and arrangements used in this
Second Amendment are, unless specified otherwise, for convenience only and shall
not be deemed to limit, amplify or modify the terms of this Second Amendment,
nor affect the meaning thereof.

        4.7.    Effectiveness. This Second Amendment shall be effective
automatically and without necessity of any further action by Borrower,
Administrative Agent or Banks when counterparts hereof have been executed by
Borrower, Administrative Agent and Required Banks, and all conditions to the
effectiveness hereof set forth herein and in the Credit Agreement have been
satisfied.

        IN WITNESS WHEREOF, the parties hereto have caused this Second Amendment
to be duly executed by their respective Authorized Officers on the date and year
first above written.

                           [Signature pages to follow]

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                                SIGNATURE PAGE TO
                      SECOND AMENDMENT TO CREDIT AGREEMENT
                                  BY AND AMONG
                   WHITING PETROLEUM CORPORATION, AS BORROWER,
                      BANK ONE, NA, AS ADMINISTRATIVE AGENT
                           AND THE BANKS PARTY THERETO

BORROWER:                                  FORTIS CAPITAL CORP.

WHITING PETROLEUM CORPORATION,             By:    /s/ David Montgomery
a Delaware corporation                            ---------------------------
                                           Name:  David Montgomery
By:    /s/ James J. Volker                 Title: Senior Vice President
       -------------------------
Name:  James J. Volker
Title: President/CEO                       By:    /s/ Darrell W. Holley
                                                  ------------------------------
                                           Name:  Darrell W. Holley
                                           Title: Managing Director

ADMINISTRATIVE AGENT:                      U.S. BANK NATIONAL ASSOCIATION

BANK ONE, NA                               By:    /s/ Matthew J. Purchase
                                                  ------------------------------
                                           Name:  Matthew J. Purchase
/s/ J. Scott Fowler                        Title: Vice President
--------------------------------
J. Scott Fowler
Director, Capital Markets

BANKS:                                     UNION BANK OF CALIFORNIA, N.A.

BANK ONE, NA                               By:    /s/ John A. Clark
                                                  ------------------------------
                                           Name:  John A. Clark
/s/ J. Scott Fowler                        Title: Vice President
--------------------------------
J. Scott Fowler
Director, Capital Markets                  By:    /s/ Sean Murphy
                                                  ------------------------------
                                           Name:  Sean Murphy
                                           Title: Vice President

WACHOVIA BANK, NATIONAL                    BANK OF SCOTLAND
 ASSOCIATION
                                           By:    /s/ Susan E. Hay
By:    /s/ Philip Trinder                         ------------------------------
       -----------------------             Name:  Susan E. Hay
Name:  Philip Trinder                      Title: Director, Business Services
Title: Vice President

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WELLS FARGO BANK, N.A.                      COMPASS BANK

By:     /s/ Laura Bumgarner                By:     /s/ John M. [Illegible]
       -----------------------                    ------------------------------
Name:  Laura Bumgarner                     Name:  John M. [Illegible]
Title: Relationship Manager                Title: Senior Vice President

BANK OF OKLAHOMA, N.A.                     NATEXIS BANQUES POPULAIRES

By:     /s/ Michael M. Logan               By:     /s/ Donovan C. Broussard
       -----------------------                    ------------------------------
Name:  Michael M. Logan                    Name:  Donovan C. Broussard
Title: Senior Vice President               Title: Vice President & Group Manager

                                           By:     /s/ Daniel Payer
COMERICA BANK - TEXAS                             ------------------------------
                                           Name:  Daniel Payer
By:     /s/ Thomas G. Rajan                Title: Vice President
       -----------------------
Name:  Thomas G. Rajan
Title: Vice President

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