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                                                                    EXHIBIT 10.6





                                 REVOLVING NOTE

$25,000,000.00                                                     May 11, 2001


         FOR VALUE RECEIVED, the undersigned PETROQUEST ENERGY, L.L.C., a
Louisiana limited liability company (hereinafter referred to as the "Borrower")
hereby unconditionally promises to pay to the order of ROYAL BANK OF CANADA (the
"Lender") at the offices of HIBERNIA NATIONAL BANK, as Administrative Agent for
the Lenders (the "Agent") at 313 Carondelet Street, New Orleans, Louisiana
70130, the principal sum of Twenty-Five Million and No/100 DOLLARS
($25,000,000.00), in lawful money of the United States of America together with
interest from the date funds are made available to the Borrower hereunder until
paid at the rates specified in the Credit Agreement (as hereinafter defined).
All payments of principal and interest due hereunder are payable at the offices
of Agent, or at such other address as Lender shall designate in writing to
Borrower.

         The principal and all accrued interest on this Note shall be due and
payable in accordance with the terms and provisions of the Credit Agreement.

         This Note is executed pursuant to that certain Amended and Restated
Credit Agreement dated May 11, 2001, among Borrower, PetroQuest Energy, Inc.,
Agent, and Lenders (the "Credit Agreement"), and is one of the Notes referred to
therein. Reference is made to the Credit Agreement and the Loan Documents (as
that term is defined in the Credit Agreement) for a statement of prepayment,
rights and obligations of Borrower, for a statement of the terms and conditions
under which the due date of this Note may be accelerated and for statements
regarding other matters affecting this Note (including without limitation the
obligations of the holder hereof to advance funds hereunder, principal and
interest payment due dates, voluntary and mandatory prepayments, exercise of
rights and remedies, payment of attorneys' fees, court costs and other costs of
collection and certain waivers by Borrower and others now or hereafter obligated
for payment of any sums due hereunder). Upon the occurrence of an Event of
Default, as that term is defined in the Credit Agreement and Loan Documents, the
holder hereof (i) may declare forthwith to be entirely and immediately due and
payable the principal balance hereof and the interest accrued hereon, and (ii)
shall have all rights and remedies of the Lender under the Credit Agreement and
Loan Documents. This Note may be prepaid in accordance with the terms and
provisions of the Credit Agreement. Reference is made to the Credit Agreement
for provisions concerning the applicable procedures for Advances under this
Note. NOTWITHSTANDING ANYTHING HEREIN CONTAINED TO THE CONTRARY, THE MAXIMUM
AGGREGATE AMOUNT OF ALL ADVANCES AT ANY TIME OUTSTANDING UNDER THIS NOTE IS
LIMITED TO THE LENDER'S REVOLVING COMMITMENT PERCENTAGE OF THE BORROWING BASE
AMOUNT THEN IN EFFECT. Unless otherwise defined herein, each capitalized term
used herein shall have the same meaning set forth in the Credit Agreement.

         If Lender declares this Note to be in default, Lender has the right
prospectively to adjust and fix the simple interest rate under this Note until
this Note is paid in full, as follows: the fixed






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default interest rate shall be equal to twenty-one (21%) percent per annum, or
three (3%) percent per annum in excess of the interest rate under this Note at
the time of default, whichever is greater. Notwithstanding the foregoing, the
holder hereof shall never be entitled to receive, collect or apply, as interest
on this Note, any amount in excess of the Maximum Rate (as such term is defined
in the Credit Agreement), and, if the holder hereof ever receives, collects, or
applies as interest, any such amount which would be excessive interest, it shall
be deemed a partial prepayment of principal and treated hereunder as such; and
if the indebtedness evidenced hereby is paid in full, any remaining excess shall
forthwith be paid to Borrower. In determining whether or not the interest paid
or payable, under any specific contingency, exceeds the Maximum Rate, Borrower
and the holder hereof shall, to the maximum extent permitted under applicable
law (i) characterize any non-principal payment as an expense, fee or premium
rather than as interest, (ii) exclude voluntary prepayments and the effects
thereof, and (iii) spread the total amount of interest throughout the entire
contemplated term of the obligations evidenced by this Note and/or referred to
in the Credit Agreement so that the interest rate is uniform throughout the
entire term of this Note; provided that, if this Note is paid and performed in
full prior to the end of the full contemplated term thereof; and if the interest
received for the actual period of existence thereof exceeds the Maximum Rate,
the holder hereof shall refund to Borrower the amount of such excess or credit
the amount of such excess against the indebtedness evidenced hereby, and, in
such event, the holder hereof shall not be subject to any penalties provided by
any laws for contracting for, charging, taking, reserving, or receiving interest
in excess of the Maximum Rate.

         If any payment of principal or interest on this Note shall become due
on a day other than a Business Day (as such term is defined in the Credit
Agreement), such payment shall be made on the next succeeding Business Day and
such extension of time shall in such case be included in computing interest in
connection with such payment.

         If this Note is placed in the hands of an attorney for collection, or
if it is collected through any legal proceeding at law or in equity or in
bankruptcy, receivership, or other court proceedings, Borrower agree to pay all
reasonable costs of collection, including, but not limited to, court costs and
reasonable attorneys' fees.

         Borrower and each surety, endorser, guarantor and other party ever
liable for payment of any sums of money payable on this Note, jointly and
severally waive presentment and demand for payment, notice of intention to
accelerate the maturity, protest, notice of protest and nonpayment, as to this
Note and as to each and all installments hereof, and agree that their liability
under this Note shall be joint, several and solidary, and shall not be affected
by any renewal or extension in the time of payment hereof, or in any
indulgences, or by any release or change in any security for the payment of this
Note, and hereby consent to any and all renewals, extensions, indulgences,
releases or changes.

         Borrower represents and warrants to Lender that loans evidenced by this
Note were entered into primarily for commercial or business purposes as provided
in La R.S. 9:3509.

         As security for the prompt and punctual payment of this Note, Borrower
collaterally assigns and pledges to Lender any rights which Borrower may have to
funds which Borrower






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maintains on deposit with Lender (with the exception of funds deposited in
tax-deferred accounts), and agrees that Lender may, upon occurrence of an Event
of Default under the Credit Agreement and the expiration of any applicable grace
period allowed to cure the Event of Default, apply such funds on deposit with
Lender against the unpaid balance of this Note.

         This Note shall be governed by and construed in accordance with the
applicable laws of the State of Louisiana.

         THIS WRITTEN NOTE, THE CREDIT AGREEMENT AND THE OTHER LOAN DOCUMENTS
SET FORTH THE ENTIRE AGREEMENT OF THE PARTIES WITH RESPECT TO THE SUBJECT MATTER
HEREOF AND SUPERSEDE ALL PRIOR WRITTEN AND ORAL UNDERSTANDINGS BETWEEN THE
BORROWER, THE GUARANTOR, THE AGENT AND THE BANKS AND ANY OTHER PARTIES WITH
RESPECT TO THE MATTERS HEREIN SET FORTH.

         EXECUTED as of the date and year first above written.

                           PETROQUEST ENERGY, L.L.C.
                           a Louisiana limited liability company

                           By:  PETROQUEST ENERGY, INC.,
                                  a Delaware corporation, as sole member

                           By: /s/ Michael O. Aldridge
                              ---------------------------------------------
                           Name:   Michael O. Aldridge
                           Title:  Senior Vice President, Chief Financial
                                     Officer and Secretary



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