Exhibit 10.1

Execution Copy

SIXTH AMENDMENT TO THIRD AMENDED

AND RESTATED CREDIT AGREEMENT

THIS SIXTH AMENDMENT TO THIRD AMENDED AND RESTATED CREDIT AGREEMENT (herein
called this “Amendment”), dated effective as of December 18, 2008 (the
“Effective Date”), is entered into by and among W&T OFFSHORE, INC., a Texas
corporation, as the borrower (the “Borrower”), the various financial
institutions parties hereto, as lenders (collectively, the “Lenders”), TORONTO
DOMINION (TEXAS) LLC, individually and as agent (in such capacity together with
any successors thereto, the “Agent”) for the Lenders, and the issuers of letters
of credit parties hereto, as issuers (collectively, the “Issuers”). Terms
defined in the Credit Agreement (as hereinafter defined) are used herein with
the same meanings as given them therein, unless the context otherwise requires.

W I T N E S S E T H

WHEREAS, the Borrower, the Lenders, the Agent and the Issuers have heretofore
executed that certain Third Amended and Restated Credit Agreement, dated as of
May 26, 2006, as amended by that certain First Amendment to Third Amended and
Restated Credit Agreement dated as of June 9, 2006, as further amended by that
certain Second Amendment to Third Amended and Restated Credit Agreement dated as
of July 27, 2006, as further amended by that certain Third Amendment to Third
Amended and Restated Credit Agreement dated as of June 7, 2007, as further
amended by that certain Waiver and Fourth Amendment to Third Amended and
Restated Credit Agreement dated as of November 6, 2007, and as further amended
by that certain Fifth Amendment to Third Amended and Restated Credit Agreement
dated as of July 24 2008 (as so amended, and as from time to time amended,
supplemented, restated or otherwise modified prior to the date hereof, the
“Credit Agreement”); and

WHEREAS, parties hereto hereby further intend to amend certain provisions of the
Credit Agreement, in each case on the terms and conditions set forth herein.

NOW, THEREFORE, in consideration of the premises and the mutual agreements
herein contained, the undersigned hereby agree as follows:

1. Amendments to Credit Agreement. The Credit Agreement is hereby amended as
follows:

(a) Section 1.1.

(i) Clause (c) of the definition of “Base Rate Margin” in Section 1.1 of the
Credit Agreement is hereby amended and restated in its entirety as follows:

“(c) with respect to Revolving Loans, the applicable rate per annum equal to:

(i) three-eighths of one percent (0.375%) per annum when the Facility Usage on
such day is less than fifty percent (50%) of the Borrowing Base on such day,

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(ii) five-eighths of one percent (0.625%) per annum when the Facility Usage on
such day is greater than or equal to fifty percent (50%) of the Borrowing Base
on such day, but less than seventy-five percent (75%) of the Borrowing Base on
such day,

(iii) seven-eighths of one percent (0.875%) per annum when the Facility Usage on
such day is greater than or equal to seventy-five percent (75%) of the Borrowing
Base on such day, but less than ninety percent (90%) of the Borrowing Base on
such day, and

(iv) one percent (1.000%) per annum when the Facility Usage on such day is
greater than or equal to ninety percent (90%) of the Borrowing Base on such
day.”

(ii) Clause (c) of the definition of “Eurodollar Margin” in Section 1.1 of the
Credit Agreement is hereby amended and restated in its entirety as follows:

“(c) with respect to Revolving Loans, the applicable rate per annum equal to:

(i) one and five-eighths percent (1.625%) per annum when the Facility Usage on
such day is less than fifty percent (50%) of the Borrowing Base on such day,

(ii) one and seven-eighths percent (1.875%) per annum when the Facility Usage on
such day is greater than or equal to fifty percent (50%) of the Borrowing Base
on such day, but less than seventy-five percent (75%) of the Borrowing Base on
such day,

(iii) two and one-eighths percent (2.125%) per annum when the Facility Usage on
such day is greater than or equal to seventy-five percent (75%) of the Borrowing
Base on such day, but less than ninety percent (90%) of the Borrowing Base on
such day, and

(iv) two and one-quarter percent (2.250%) per annum when the Facility Usage on
such day is greater than or equal to ninety percent (90%) of the Borrowing Base
on such day.”

 

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(b) Section 7.6. Section 7.6 of the Credit Agreement is hereby amended and
restated in its entirety as follows:

“Section 7.6 Limitation on Distributions; Redemptions and Prepayments of
Indebtedness. No Restricted Person will make any Distribution or will redeem,
purchase, retire, prepay, repay or defease any Indebtedness (other than the
Obligations) prior to the original maturity thereof, except:

(a) Distributions by Borrower to any of its shareholders on any date, provided
that all Distributions made pursuant to this clause (a) in any Fiscal Year shall
not exceed the Available Distribution Amount,

(b) Distributions by Subsidiaries of Borrower without limitation to Borrower, or

(c) (x) the purchase, redemption, acquisition or retirement of common stock of
the Borrower and/or (y) the redemption, purchase, prepayment, repayment or
defeasance of all or any portion of the Bonds described in Section 7.1(h), in an
aggregate amount not to exceed $100,000,000 from and after December 18, 2008;

provided that no such Distribution, redemption, purchase, acquisition,
retirement, prepayment, repayment or defeasance described in this Section 7.6
(including pursuant to the immediately following proviso) shall be permitted if
(i) an Event of Default has occurred and is continuing, (ii) an Event of Default
would occur as a result of such Distribution, redemption, purchase, acquisition,
retirement, prepayment, repayment or defeasance, or (iii) a Borrowing Base
Deficiency has occurred and is continuing or would result therefrom; provided,
further that, notwithstanding Section 7.6(c) but subject to the immediately
preceding proviso, (A) the Borrower may pay interest on the Bonds on the stated,
scheduled dates for payment of interest set forth in the applicable Indenture
and (B) the Borrower may redeem, repurchase, prepay or defease the Bonds (x) on
the scheduled maturity date for the Bonds, (y) in the principal amount that is
required to be repaid or prepaid under the applicable Indenture on each stated,
scheduled date for repayment or prepayment of principal thereunder or (z) with
the written consent of the Required Lenders.”

2. Representations and Warranties. The Borrower and each Restricted Person (if
any) hereby represents and warrants that after giving effect hereto:

(a) the representations and warranties of the Borrower and such Restricted
Person (if any) contained in the Loan Documents are true and correct in all
material respects on and as of the Effective Date, other than those
representations and warranties that expressly relate solely to a specific
earlier date, which shall remain correct in all material respects as of such
earlier date;

(b) the execution, delivery and performance by the Borrower and such Restricted
Person (if any) of this Amendment are within their corporate or limited
liability powers, have been duly authorized by all necessary action, require, in
respect of any of them, no action by or in respect of, or filing with, any
governmental authority which has not been performed or obtained and do not
contravene, or constitute a default under, any provision of Law or regulation or
the articles of incorporation or the bylaws of any of them or any agreement,
judgment, injunction, order, decree or other instrument binding upon the
Borrower or such Restricted Person (if any) or result in the creation or
imposition of any Lien on any asset of any of them except as contemplated by the
Loan Documents;

 

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(c) the execution, delivery and performance by the Borrower and such Restricted
Person of this Amendment has been duly authorized by all necessary action
required on their part and this Amendment constitutes the legal, valid and
binding obligation of each of them enforceable against them in accordance with
its terms;

(d) no Default or Event of Default has occurred and is continuing; and

(e) pursuant to that certain W&T Offshore, Inc. Restructuring Agreement dated
effective as of January 1, 2008, among the Borrower and the Subsidiary Merger
Parties described therein, (i) each of Offshore Energy I LLC, a Delaware limited
liability company (“Offshore Energy I”), Offshore Energy II LLC, a Delaware
limited liability company (“Offshore Energy II”), Offshore Energy III LLC, a
Delaware limited liability company (“Offshore Energy III”), Gulf of Mexico Oil
and Gas Properties LLC, a Delaware limited liability company (“Oil and Gas
LLC”), and Offshore Shelf LLC, a Delaware limited liability company (“Offshore
Shelf LLC”; and together with Offshore Energy I, Offshore Energy II, Offshore
Energy III, and Oil and Gas LLC, the “Subsidiary Merger Parties”), has merged
with and into the Borrower (the “Mergers”), (ii) the separate existence of each
of the Subsidiary Merger Parties has ceased, (iii) the Borrower is the sole
surviving entity of each of the Mergers and is and remains a corporation
incorporated under the laws of the State of Texas, (iv) all of the properties,
rights, privileges, powers and franchises of each of the Subsidiary Merger
Parties have vested in the Borrower, and (v) all debts, obligations, liabilities
and duties of each of the Subsidiary Merger Parties have been assumed by the
Borrower and have become the debts, obligations, liabilities and duties of the
Borrower.

3. Effectiveness. This Amendment shall be deemed effective as of the Effective
Date when the Agent shall have received counterparts hereof duly executed by the
Borrower, the Agent and the Required Lenders.

4. Ratification; Loan Document. This Amendment shall be deemed to be an
amendment to the Credit Agreement, and the Credit Agreement, as hereby amended,
is hereby ratified, approved and confirmed in each and every respect. The
Borrower and each other Restricted Person (if any) hereby ratifies, approves and
confirms in every respect all the terms, provisions, conditions and obligations
of the Loan Documents (including, without limitation, all Security Documents) to
which it is a party. All references to the Credit Agreement in any Loan Document
or in any other document, instrument, agreement or writing shall hereafter be
deemed to refer to the Credit Agreement as hereby amended. Without limiting the
foregoing, the Borrower (a) hereby ratifies, assumes, accepts, approves and
confirms in every respect all the terms, provisions, conditions and obligations
of the Loan Documents (including, without limitation, all Security Documents)
heretofore entered into by a Subsidiary Merger Party or to which any Subsidiary
Merger Party is a party, and (b) hereby agrees to promptly deliver, file or
record or cause to be delivered, filed or recorded, any financing statements,
continuation statements, extension agreements, modifications to mortgages and
other security documents, ratifications, documents, instruments or agreements in
form and substance satisfactory to the Agent, which the Agent reasonably
requests in connection with the Mergers (or otherwise to

 

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evidence or provide notice of the Mergers) for the purpose of perfecting,
confirming, ratifying, protecting, preserving or maintaining the Liens or other
rights in the Collateral securing the Obligations. Notwithstanding anything
herein to the contrary, it is understood and agreed that the Mergers did not
cause or result in a disposition of any Collateral free of any security
interests under the Security Documents. This Amendment is a Loan Document.

5. Costs And Expenses. As provided in Section 10.4 of the Credit Agreement, the
Borrower agrees to reimburse Agent for all reasonable costs and expenses
incurred by or on behalf of Agent (including attorneys’ fees, consultants’ fees
and engineering fees, travel costs and miscellaneous expenses) in connection
with this Amendment and any other agreements, documents, instruments, releases,
terminations or other collateral instruments delivered by the Agent in
connection with this Amendment.

6. GOVERNING LAW. THIS AMENDMENT SHALL BE DEEMED A CONTRACT AND INSTRUMENT MADE
UNDER THE LAWS OF THE STATE OF NEW YORK AND SHALL BE CONSTRUED AND ENFORCED IN
ACCORDANCE WITH AND GOVERNED BY THE LAWS OF THE STATE OF NEW YORK AND THE LAWS
OF THE UNITED STATES OF AMERICA, WITHOUT REGARD TO PRINCIPLES OF CONFLICTS OF
LAW.

7. Severability. Any provision of this Amendment that is prohibited or
unenforceable in any jurisdiction shall, as to such provision and such
jurisdiction, be ineffective to the extent of such prohibition or
unenforceability without invalidating the remaining provisions of this Amendment
or affecting the validity or enforceability of such provision in any other
jurisdiction.

8. Counterparts. This Amendment may be executed in any number of counterparts,
all of which taken together shall constitute one and the same instrument, and
any party hereto may execute this Amendment by signing one or more counterparts.
Any signature hereto delivered by a party by facsimile or electronic
transmission shall be deemed to be an original signature hereto.

9. Successors and Assigns. This Amendment shall be binding upon the Borrower and
its successors and permitted assigns and shall inure, together with all rights
and remedies of each Lender Party hereunder, to the benefit of each Lender Party
and its successors, transferees and assigns.

 

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IN WITNESS WHEREOF, the parties hereto have caused this Amendment to be executed
by their respective officers thereunto duly authorized as of the day and year
first above written.

 

BORROWER: W&T OFFSHORE, INC. By:   /s/ John D. Gibbons Name:   John D. Gibbons
Title:   Chief Financial Officer

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TORONTO DOMINION (TEXAS) LLC, as Agent and Lender By:   /s/ Jackie Barrett Name:
  Jackie Barrett Title:   Authorized Signatory

THE TORONTO-DOMINION BANK,

as Issuer

By:   /s/ Deborah Gravinese Name:   Deborah Gravinese Title:   Vice President

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FORTIS CAPITAL CORP. as Issuer and Lender By:   /s/ David Montgomery Name:  
David Montgomery Title:   Director By:   /s/ Darrell Holley Name:   Darrell
Holley Title:   Managing Director

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BMO CAPITAL MARKETS FINANCING, INC., as Lender By:   /s/ James V. Ducote Name:  
James V. Ducote Title:   Director

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BANK OF SCOTLAND, as Lender By:   /s/ Julia R. Franklin Name:   Julia R.
Franklin Title:   Assistant Vice President

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NATIXIS, as Lender By:   /s/ Donovan Broussard Name:   Donovan Broussard Title:
  Managing Director By:   /s/ Liana Tchernysheva Name:   Liana Tchernysheva
Title:   Director

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GE BUSINESS FINANCIAL SERVICES, INC.

f/k/a MERRILL LYNCH BUSINESS FINANCIAL

SERVICES, INC.,

as Lender

By:   /s/ Randall F. Hornick Name:   Randall F. Hornick Title:   Authorized
Signatory

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SOCIÉTÉ GÉNÉRALE, as Lender By:   /s/ Stephen W. Warfel Name:   Stephen W.
Warfel Title:   Managing Director

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AMEGY BANK NATIONAL ASSOCIATION, as Lender By:   /s/ W. Bryan Chapman Name:   W.
Bryan Chapman Title:   Senior Vice President

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BNP PARIBAS, as Lender By:   /s/ Russell Otts Name:   Russell Otts Title:  
Director By:   /s/ Douglas R. Liftman Name:   Douglas R. Liftman Title:  
Managing Director

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GUARANTY BANK, FSB, as Lender By:   /s/ Christopher S. Parada Name:  
Christopher S. Parada Title:   Senior Vice President

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SUNTRUST BANK, as Lender By:   /s/ James M. Warren Name:   James M. Warren
Title:   Managing Director

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MORGAN STANLEY BANK, as Lender By:   /s/ Melissa James Name:   Melissa James
Title:   Authorized Signatory

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THE BANK OF NOVA SCOTIA, as Lender By:   /s/ David G. Mills Name:   David G.
Mills Title:   Managing Director

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RAYMOND JAMES BANK, FSB, as Lender By:   /s/ James M. Armstrong Name:   James M.
Armstrong Title:   Vice President