<PAGE>

                                    GUARANTY


         THIS GUARANTY (this "Guaranty") is made as of the 14 day of May, 2003,
by PetroQuest Energy, Inc. a Delaware corporation (the "Guarantor") in favor of
the Agent, for the benefit of the Lenders, under the Credit Agreement referred
to below;


                                   WITNESSETH:

         WHEREAS, PetroQuest Energy, LLC, a Louisiana limited liability company
(the "Borrower"); Guarantor; Bank One, NA, a national banking association having
its Borrower office in Chicago, Illinois, as Agent (the "Agent"), and certain
other Lenders from time to time party thereto have entered into a certain
Amended and Restated Credit Agreement dated as of even date herewith (as same
may be amended or modified from time to time, the "Credit Agreement"),
providing, subject to the terms and conditions thereof, for extensions of credit
to be made by the Lenders to the Borrower;

         WHEREAS, it is a condition precedent to the Agent and the Lenders
executing the Credit Agreement that the Guarantor execute and deliver this
Guaranty whereby it shall guarantee the payment when due, subject to Section 9
hereof, of all Guaranteed Obligations, as defined below; and

         WHEREAS, in consideration of the financial and other support that the
Borrower has provided, and such financial and other support as the Borrower may
in the future provide, to the Guarantor, and in order to induce the Lenders and
the Agent to enter into the Credit Agreement, and the Lenders and their
Affiliates to enter into one or more Rate Management Transactions with the
Borrower, and because the Guarantor has determined that executing this Guaranty
is in its interest and to its financial benefit, the Guarantor is willing to
guarantee the obligations of the Borrower under the Credit Agreement, any Note,
any Rate Management Transaction, and the other Loan Documents;

         NOW, THEREFORE, in consideration of the premises and other good and
valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, the parties hereto agree as follows:

         SECTION  l.1.  Selected Terms Used Herein.

         "Guaranteed Obligations" is defined in Section 3 below.

         "Rate Management Transaction" means any transaction (including an
agreement with respect thereto) now existing or hereafter entered into between
the Borrower and any Lender or Affiliate thereof which is a rate swap, basis
swap, forward rate transaction, commodity swap, commodity option, equity or
equity index swap, equity or equity index option, bond option, interest rate
option, foreign exchange transaction, cap transaction, floor transaction, collar
transaction, forward

<PAGE>
transaction, currency swap transaction, cross-currency rate swap transaction,
currency option or any other similar transaction (including any option with
respect to any of these transactions) or any combination thereof, whether linked
to one or more interest rates, foreign currencies, commodity prices, equity
prices or other financial measures.

         "Rate Management Obligations" means any and all obligations of the
Borrower, whether absolute or contingent and howsoever and whensoever created,
arising, evidenced or acquired (including all renewals, extensions and
modifications thereof and substitutions therefor), under (i) any and all Rate
Management Transactions, and (ii) any and all cancellations, buy backs,
reversals, terminations or assignments of any Rate Management Transactions.

         SECTION 1.2. Terms in Credit Agreement. Other capitalized terms used
herein but not defined herein shall have the meaning set forth in the Credit
Agreement.

         SECTION 2.1. Representations and Warranties. The Guarantor represents
and warrants (which representations and warranties shall be deemed to have been
renewed upon each Borrowing Date under the Credit Agreement) that:

                  (a) It is a corporation duly and properly organized, validly
existing and in good standing under the laws of the state of Delaware and has
all requisite authority to conduct its business in each jurisdiction in which
its business is conducted.

                  (b) It has the power and authority and legal right to execute
and deliver this Guaranty and to perform its obligations hereunder. The
execution and delivery by it of this Guaranty and the performance of its
obligations hereunder have been duly authorized by proper corporate proceedings,
and this Guaranty constitutes a legal, valid and binding obligation of the
Guarantor enforceable against it in accordance with its terms, except as
enforceability may be limited by bankruptcy, insolvency or similar laws
affecting the enforcement of creditors' rights generally.

                  (c) Neither the execution and delivery by it of this Guaranty,
nor the consummation of the transactions herein contemplated, nor compliance
with the provisions hereof will violate (i) any law, rule, regulation, order,
writ, judgment, injunction, decree or award binding on it or any of its
subsidiaries or (ii) its articles or certificate of incorporation, partnership
agreement, certificate of partnership, articles or certificate of organization,
by-laws, or operating or other management agreement, as the case may be, or
(iii) the provisions of any indenture, instrument or agreement to which it or
any of its subsidiaries is a party or is subject, or by which it, or its
Property, is bound, or conflict with or constitute a default thereunder, or
result in, or require, the creation or imposition of any Lien in, of or on the
Property of the Guarantor or a subsidiary thereof pursuant to the terms of any
such indenture, instrument or agreement. No order, consent, adjudication,
approval, license, authorization, or validation of, or filing, recording or
registration with, or exemption by, or other action in respect of any
governmental or public body or authority, or any subdivision thereof, which has
not been obtained by it or any of its subsidiaries, is required to be obtained
by it or any of its subsidiaries in connection with the execution and delivery
of this Guaranty or the performance by it of its obligations hereunder or the
legality, validity, binding effect or enforceability of this Guaranty.


                                       2
<PAGE>

         SECTION 2.2. Covenants. The Guarantor covenants that, so long as any
Lender has any Commitment outstanding under the Credit Agreement, any Rate
Management Transaction remains in effect or any of the Guaranteed Obligations
shall remain unpaid, that it will, and, if necessary, will enable the Borrower
to, fully comply with those covenants and agreements set forth in the Credit
Agreement.

         SECTION 3. The Guaranty. Subject to Section 9 hereof, the Guarantor
hereby absolutely and unconditionally guarantees, as primary obligor and not as
surety, the full and punctual payment (whether at stated maturity, upon
acceleration or early termination or otherwise, and at all times thereafter) and
performance of the Obligations and the Rate Management Obligations, including
without limitation any such Obligations or Rate Management Obligations incurred
or accrued during the pendency of any bankruptcy, insolvency, receivership or
other similar proceeding, whether or not allowed or allowable in such proceeding
(collectively, subject to the provisions of Section 9 hereof, being referred to
collectively as the "Guaranteed Obligations"). Upon failure by the Borrower to
pay punctually any such amount, the Guarantor agrees that it shall forthwith on
demand pay to the Agent for the benefit of the Lenders and, if applicable, their
Affiliates, the amount not so paid at the place and in the manner specified in
the Credit Agreement, any Note, any Rate Management Transaction or the relevant
Loan Document, as the case may be. This Guaranty is a guaranty of payment and
not of collection. The Guarantor hereby waives any right to require the Lender
to sue the Borrower, any other guarantor, or any other person obligated for all
or any part of the Guaranteed Obligations, or otherwise to enforce its payment
against any collateral securing all or any part of the Guaranteed Obligations.

         SECTION 4. Guaranty Unconditional. Subject to Section 9 hereof, the
obligations of the Guarantor hereunder shall be unconditional and absolute and,
without limiting the generality of the foregoing, shall not be released,
discharged or otherwise affected by:

         (i) any extension, renewal, settlement, compromise, waiver or release
         in respect of any of the Guaranteed Obligations, by operation of law or
         otherwise, or any obligation of any other guarantor of any of the
         Guaranteed Obligations, or any default, failure or delay, willful or
         otherwise, in the payment or performance of the Guaranteed Obligations;

         (ii) any modification or amendment of or supplement to the Credit
         Agreement, any Note, any Rate Management Transaction or any other Loan
         Document;

         (iii) any release, nonperfection or invalidity of any direct or
         indirect security for any obligation of the Borrower under the Credit
         Agreement, any Note, the Security Agreement, any Rate Management
         Transaction, any other Loan Document, or any obligations of any other
         guarantor of any of the Guaranteed Obligations, or any action or
         failure to act by the Agent, any Lender or any Affiliate of any Lender
         with respect to any collateral securing all or any part of the
         Guaranteed Obligations;

         (iv) any change in the corporate existence, structure or ownership of
         the Borrower or any other guarantor of any of the Guaranteed
         Obligations, or any insolvency, bankruptcy,





                                       3
<PAGE>

         reorganization or other similar proceeding affecting the Borrower, or
         any other guarantor of the Guaranteed Obligations, or its assets or any
         resulting release or discharge of any obligation of the Borrower, or
         any other guarantor of any of the Guaranteed Obligations;

         (v) the existence of any claim, setoff or other rights which the
         Guarantor may have at any time against the Borrower, any other
         guarantor of any of the Guaranteed Obligations, the Agent, any Lender
         or any other Person, whether in connection herewith or any unrelated
         transactions;

         (vi) any invalidity or unenforceability relating to or against the
         Borrower, or any other guarantor of any of the Guaranteed Obligations,
         for any reason related to the Credit Agreement, any Rate Management
         Transaction, any other Loan Document, or any provision of applicable
         law or regulation purporting to prohibit the payment by the Borrower,
         or any other guarantor of the Guaranteed Obligations, of the Borrower
         of or interest on any Note or any other amount payable by the Borrower
         under the Credit Agreement, any Note, any Rate Management Transaction
         or any other Loan Document; or

         (vii) any other act or omission to act or delay of any kind by the
         Borrower, any other guarantor of the Guaranteed Obligations, the Agent,
         any Lender or any other Person or any other circumstance whatsoever
         which might, but for the provisions of this paragraph, constitute a
         legal or equitable discharge of the Guarantor's obligations hereunder.

         SECTION 5. Discharge Only Upon Payment In Full: Reinstatement In
Certain Circumstances. The obligations of the Guarantor hereunder shall remain
in full force and effect until all Guaranteed Obligations shall have been
indefeasibly paid in full, the Commitments under the Credit Agreement shall have
terminated or expired and all Rate Management Transactions have terminated or
expired. If at any time any payment of the Borrower of or interest on any Note
or any other amount payable by the Borrower or any other party under the Credit
Agreement, any Rate Management Transaction or any other Loan Document is
rescinded or must be otherwise restored or returned upon the insolvency,
bankruptcy or reorganization of the Borrower or otherwise, the Guarantor's
obligations hereunder with respect to such payment shall be reinstated as though
such payment had been due but not made at such time.

         SECTION 6. Waivers. The Guarantor herby irrevocably waives acceptance
hereof, presentment, demand, protest and, to the fullest extent permitted by
law, any notice not provided for herein, as well as any requirement that at any
time any action be taken by any Person against the Borrower, any other guarantor
of any of the Guaranteed Obligations, or any other Person.

         SECTION 7. Subrogation. The Guarantor hereby agrees not to assert any
right, claim or cause of action, including, without limitation, a claim for
subrogation, reimbursement, indemnification or otherwise, against the Borrower
arising out of or by reason of this Guaranty or the obligations hereunder,
including, without limitation, the payment or securing or purchasing of any of
the Guaranteed Obligations by the Guarantor unless and until the Guaranteed
Obligations are indefeasibly paid in full, any commitment to lend under the
Credit Agreement and any other Loan Documents is terminated and all Rate
Management Transactions have terminated or expired.


                                       4
<PAGE>


         SECTION 8. Stay of Acceleration. If acceleration of the time for
payment of any of the Guaranteed Obligations is stayed upon the insolvency,
bankruptcy or reorganization of the Borrower, all such amounts otherwise subject
to acceleration under the terms of the Credit Agreement, any Note, any Rate
Management Transaction or any other Loan Document shall nonetheless be payable
by the Guarantor hereunder forthwith on demand by the Agent made at the request
of the Required Lenders.

         SECTION 9. Limitation on Obligations. (a) The provisions of this
Guaranty are severable, and in any action or proceeding involving any state
corporate law, or any state, federal or foreign bankruptcy, insolvency,
reorganization or other law affecting the rights of creditors generally, if the
obligations of the Guarantor under this Guaranty would otherwise be held or
determined to be avoidable, invalid or unenforceable on account of the amount of
the liability of the Guarantor under this Guaranty, then, notwithstanding any
other provision of this Guaranty to the contrary, the amount of such liability
shall, without any further action by the Guarantor, the Agent or any Lender, be
automatically limited and reduced to the highest amount that is valid and
enforceable as determined in such action or proceeding (such highest amount
determined hereunder being the "Maximum Liability"). This Section 9(a) with
respect to the Maximum Liability of the Guarantor is intended solely to preserve
the rights of the Agent hereunder to the maximum extent not subject to avoidance
under applicable law, and neither the Guarantor nor any other person or entity
shall have any right or claim under this Section 9(a) with respect to the
Maximum Liability, except to the extent necessary so that the obligations of the
Guarantor hereunder shall not be rendered voidable under applicable law.

         SECTION 10. Application of Payments. All payments received by the Agent
hereunder shall be applied by the Agent to payment of the Guaranteed Obligations
in the following order unless a court of competent jurisdiction shall otherwise
direct:

                  (a) FIRST, to payment of all costs and expenses of the Agent
         incurred in connection with the collection and enforcement of the
         Guaranteed Obligations or of any security interest granted to the Agent
         in connection with any collateral securing the Guaranteed Obligations;

                  (b) SECOND, to payment of that portion of the Guaranteed
         Obligations constituting accrued and unpaid interest and fees, pro rata
         among the Lenders and their Affiliates in accordance with the amount of
         such accrued and unpaid interest and fees owing to each of them;

                  (c) THIRD, to payment of the Borrower of the Guaranteed
         Obligations and the net early termination payments and any other Rate
         Management Obligations then due and unpaid from the Borrower to any of
         the Lenders or their Affiliates, pro rata among the Lenders and their
         Affiliates in accordance with the amount of such Borrower and such net
         early termination payments and other Rate Management Obligations then
         due and unpaid owing to each of them; and



                                       5
<PAGE>

                  (d) FOURTH, to payment of any Guaranteed Obligations (other
         than those listed above) pro rata among those parties to whom such
         Guaranteed Obligations are due in accordance with the amounts owing to
         each of them.

         SECTION 11. Notices. All notices, requests and other communications to
any party hereunder shall be given or made by telecopier or other writing and
telecopied, or mailed or delivered to the intended recipient at its address or
telecopier number set forth on the signature pages hereof or such other address
or telecopy number as such party may hereafter specify for such purpose by
notice to the Agent in accordance with the provisions of Article XIII of the
Credit Agreement. Except as otherwise provided in this Guaranty, all such
communications shall be deemed to have been duly given when transmitted by
telecopier, or personally delivered or, in the case of a mailed notice sent by
certified mail return-receipt requested, on the date set forth on the receipt
(provided, that any refusal to accept any such notice shall be deemed to be
notice thereof as of the time of any such refusal), in each case given or
addressed as aforesaid.

         SECTION 12. No Waivers. No failure or delay by the Agent or any Lenders
in exercising any right, power or privilege hereunder shall operate as a waiver
thereof nor shall any single or partial exercise thereof preclude any other or
further exercise thereof or the exercise of any other right, power or privilege.
The rights and remedies provided in this Guaranty, the Credit Agreement, any
Note, any Rate Management Transaction and the other Loan Documents shall be
cumulative and not exclusive of any rights or remedies provided by law.

         SECTION 13. No Duty to Advise. The Guarantor assumes all responsibility
for being and keeping itself informed of the Borrower's financial condition and
assets, and of all other circumstances bearing upon the risk of nonpayment of
the Guaranteed Obligations and the nature, scope and extent of the risks that
the Guarantor assumes and incurs under this Guaranty, and agrees that neither
the Agent nor any Lender has any duty to advise the Guarantor of information
known to it regarding those circumstances or risks.

         SECTION 14. Successors and Assigns. This Guaranty is for the benefit of
the Agent and the Lenders and their respective successors and permitted assigns
and in the event of an assignment of any amounts payable under the Credit
Agreement, any Note, any Rate Management Transaction, or the other Loan
Documents, the rights hereunder, to the extent applicable to the indebtedness so
assigned, shall be transferred with such indebtedness. This Guaranty shall be
binding upon the Guarantor and their respective successors and permitted
assigns.

         SECTION 15. Changes in Writing. Neither this Guaranty nor any provision
hereof may be changed, waived, discharged or terminated orally, but only in
writing signed by the Guarantor and the Required Lenders or the Agent with the
consent of the Required Lenders.

         SECTION 16. Costs of Enforcement. The Guarantor hereby agrees to pay
all costs and expenses including, without limitation, all court costs and
attorneys' fees and expenses paid or incurred by the Agent or any Lender or any
Affiliate of any Lender in endeavoring to collect all or any part of the
Guaranteed Obligations from, or in prosecuting any action against, the Borrower,
the Guarantor or any other guarantor of all or any part of the Guaranteed
Obligations.

                                       6
<PAGE>

         SECTION 17. GOVERNING LAW; SUBMISSION TO JURISDICTION; WAIVER OF JURY
TRIAL. THIS GUARANTY SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE
LAW OF THE STATE OF TEXAS. THE GUARANTOR HEREBY SUBMITS TO THE NONEXCLUSIVE
JURISDICTION OF THE UNITED STATES DISTRICT COURT FOR THE SOUTHERN DISTRICT OF
TEXAS AND OF ANY TEXAS STATE COURT SITTING IN HOUSTON, TEXAS AND FOR PURPOSES OF
ALL LEGAL PROCEEDINGS ARISING OUT OF OR RELATING TO THIS GUARANTY (INCLUDING,
WITHOUT LIMITATION, ANY OF THE OTHER LOAN DOCUMENTS) OR THE TRANSACTIONS
CONTEMPLATED HEREBY. THE GUARANTOR HEREBY IRREVOCABLY WAIVES, TO THE FULLEST
EXTENT PERMITTED BY LAW, ANY OBJECTION WHICH IT MAY NOW OR HEREAFTER HAVE TO THE
LAYING OF THE VENUE OF ANY SUCH PROCEEDING BROUGHT IN SUCH A COURT AND ANY CLAIM
THAT ANY SUCH PROCEEDING BROUGHT IN SUCH A COURT HAS BEEN BROUGHT IN AN
INCONVENIENT FORUM. THE GUARANTOR, AND THE AGENT AND THE LENDERS ACCEPTING THIS
GUARANTY, HEREBY IRREVOCABLY WAIVES ANY AND ALL RIGHT TO TRIAL BY JURY IN ANY
LEGAL PROCEEDING ARISING OUT OF OR RELATING TO THIS GUARANTY OR THE TRANSACTIONS
CONTEMPLATED HEREBY.

         SECTION 18. Taxes. etc. All payments required to be made by any of the
Guarantor hereunder shall be made without setoff or counterclaim and free and
clear of and without deduction or withholding for or on account of, any present
or future taxes, levies, imposts, duties or other charges of whatsoever nature
imposed by any government or any political or taxing authority thereof (but
excluding Excluded Taxes), provided, however, that if the Guarantor is required
by law to make such deduction or withholding, then Guarantor shall forthwith (i)
pay to the Agent or any Lender, as applicable, such additional amount as results
in the net amount received by the Agent or any Lender, as applicable, equaling
the full amount which would have been received by the Agent or any Lender, as
applicable, had no such deduction or withholding been made, (ii) pay the full
amount deducted to the relevant authority in accordance with applicable law, and
(iii) furnish to the Agent or any Lender, as applicable, certified copies of
official receipts evidencing payment of such withholding taxes within 30 days
after such payment is made.



                                       7
<PAGE>



         IN WITNESS WHEREOF, the Guarantor has caused this Guaranty to be duly
executed by its authorized officer as of the day and year first above written.

                                      PETROQUEST ENERGY, INC.

                                      By: /s/ MICHAEL O. ALDRIDGE

                                      Name:   Michael O. Aldridge

                                      Title:  Chief Financial Officer




                                       8