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                                                                    EXHIBIT 3.27

                          CERTIFICATE OF INCORPORATION
                                       OF
                            TWS OF CADDO COUNTY, INC.



STATE OF OKLAHOMA  )
                   ) SS:
COUNTY OF OKLAHOMA )


     1.   The name of the Corporation is TWS of Caddo County, Inc.

     2.   The address of the registered office in the State of Oklahoma is 700
Bank of Oklahoma Plaza, 201 Robert S. Kerr Avenue, Oklahoma 73102, and the
registered agent is John B. Todd.

     3.   The name and mailing address of each incorporator is:



                 NAME                                       ADDRESS
                                        

     James E. Britton                      100 North Broadway, Suite 2060
                                           Oklahoma City, Oklahoma 73102.


     4.   The purposes for which the Corporation is formed are as follows:

A.   To engage in any lawful act or activity for which corporations may be
     organized under the general corporation law of Oklahoma as now existing or
     hereafter enacted;

B.   To buy, sell, lease, assign, convey in trust, pledge, sub-divide, exchange,
     improve, cultivate, develop, maintain, construct, mortgage or otherwise
     acquire, transfer or encumber, and generally deal in and with any real
     estate, improved or unimproved, as may be now or hereafter permitted by the
     Constitution and laws of the State of Oklahoma and wheresoever situated
     within or without the State of Oklahoma;

C.   To engage in all aspects of natural energy exploration and development as
     principal, partner, joint venturer, limited partner, developer, operator,
     owner or otherwise, including without limitation the following:

     (1)  To operate to the full extent permitted by the laws of the State of
          Oklahoma a drilling, service and supply company in the State of
          Oklahoma or any place authorized;

     (2)  To drill wells for the production of oil and gas for the Corporation's
          own account and for others by contract, turnkey or day work and
          conduct and perform oilfield services;

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     (3)  To engage in the treatment, servicing and supervision of wells for the
          production of water, oil, gas, casinghead gas, uranium, sulphur, and
          other mineral or hydrocarbon substances;

     (4)  To engage in the consultation and evaluation of water, oil, gas,
          casinghead gas, uranium, sulphur and other mineral or hydrocarbon
          substances; to engage in the supervision of drilling, completion and
          recompletion operations of wells for the primary and secondary
          production of water, oil, gas, casinghead gas, uranium, sulphur, and
          other mineral or hydrocarbon substances;

     (5)  To manufacture, buy or sell acids, solvents, cleaning fluids,
          explosives, and other chemicals and substances which are used in the
          drilling, treatment and servicing of wells for the production of
          water, oil, gas, casing head gas, uranium, sulphur, and other mineral
          or hydro-carbon substances;

     (6)  To manufacture, buy or sell equipment used for introducing into wells
          any such acids, solvents, cleaning fluids, explosives, and other
          chemicals for the treatment and servicing of wells;

     (7)  To buy, sell or lease interests in land for the purpose of exploring
          for and producing water, oil, gas, casing head gas, uranium, sulphur
          and other mineral or hydro-carbon substances; to engage in operations
          for the exploration, drilling and development of such land; to
          construct pipelines and engage in any other activities necessary for
          the transportation and marketing of water, oil, casinghead gas,
          uranium, sulphur and other mineral or hydrocarbon substances; to
          engage in all activities necessary for the sale and disposal of such
          substances, including the establishment of wholesale and retail
          outlets;

     (8)  To engage in the treatment and servicing, by chemical or mechanical
          means, of boilers, pipelines, machines, wells, gathering tanks, and
          other mechanical equipment or apparatus used for the production of
          water, oil, gas, casinghead gas, uranium, sulphur and other mineral or
          hydrocarbon substances;

     (9)  To manufacture, buy or sell equipment for use in the treatment and
          servicing, by chemical or mechanical means, of boilers, pipelines,
          wells, gathering tanks, and other mechanical equipment or apparatus
          used for the production of water, oil, gas, casinghead gas, uranium,
          sulphur and other mineral or hydrocarbon substances; and

     (10) To engage in research, exploration, laboratory and development work
          relating to any substance, compound, mixture, chemical, explosive,
          acid or solvent, and any process, machine, or equipment which is used
          or produced in the drilling of water, oil, gas, casinghead gas,
          uranium, sulphur and other mineral or hydrocarbon substances;

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D.   To buy, sell, own and exploit letters patent, licenses under letters
     patent, processes of manufacture, secret or otherwise, copyrights,
     trademarks, and tradenames and to grant licenses or sublicenses thereunder
     for any and all lawful considerations, and to hold, own, use and sell
     rights under such patents, licenses, copyrights, trademarks, and tradenames
     or processes, or products produced pursuant to the disclosure thereof;

E.   To build, construct, equip, own, control, lease, or otherwise acquire, and
     operate all kinds and classes of real and personal property wheresoever
     situated within or without the State of Oklahoma;

F.   To acquire by lease, gift or purchase, sell, assign, exchange, convey in
     trust and pledge all types of transportation equipment necessary for or
     incident to the transportation and delivery of products and merchandise
     offered for sale by the Corporation, and to apply for, receive and hold
     licenses and certificates of convenience and necessity for the operation of
     transportation facilities for the transportation of the products and
     merchandise of the Corporation, for its own benefit or for the account of
     its customers or principals;

G.   To borrow money with or without evidencing the same with bonds, notes or
     other evidence of indebtedness, with or without securing the same, and with
     power to execute mortgages, or deeds of trust, and instruments to secure
     indebtedness, to loan money upon such security as the Corporation might
     desire, and to make all necessary contracts either to borrow or to loan
     money and to secure or take security for the same as the Corporation might
     desire;

H.   To subscribe or cause to be subscribed, acquire, hold, encumber, sell or
     otherwise dispose of or deal in shares of the capital stock, bonds,
     debentures, notes or other securities or evidence of indebtedness of this
     Corporation and any other person, corporation, association, trust or other
     entity, whether domestic or foreign, whether now or hereafter organized and
     to exercise all the rights, powers and privileges of ownership, and to deal
     in stocks and securities either as an agent or broker or otherwise;

I.   To promote or to aid in any manner, financially or otherwise, any person,
     corporation, association, trust or other entity of which any stocks, bonds
     or other evidence of indebtedness or securities are held directly or
     indirectly by the Corporation; and to guarantee the contracts, dividends,
     stocks, bonds, notes and other obligations of such other persons,
     corporations, associations, trusts or other entities and to do any other
     acts or things designed to protect, preserve, improve or enhance the value
     of such stocks, bonds or other evidence of indebtedness or securities;

J.   To buy, sell, lease, exchange, develop, mortgage or otherwise acquire,
     transfer or encumber any interests in minerals, and to manage, control and
     exploit mineral interests and collect the revenue arising therefrom;

K.   To exercise any of the powers, hereinbefore or hereinafter set forth, in
     conjunction with others, in the capacity of principal, agent, partner,
     stockholder, or holder of any interest in

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     shares of stock, joint venturer or as a member of a partnership, syndicate
     or pool, for the Corporation or others; and

L.   To do all things necessary or convenient for the accomplishment of any of
     the foregoing purposes, and to have and exercise all powers conferred by
     the laws of Oklahoma upon corporations, as such laws are now in effect or
     may at any time hereafter be amended.

     5.   The number of shares which the Corporation shall have authority to
issue is Five million (5,000,000). The designation of each class, the number of
shares for each class, and the par value of the shares of each class are as
follows:

<Table>
<Caption>
   CLASS           NO. OF SHARES         PAR VALUE               TOTAL VALUE
   -----           -------------         ---------               -----------
                                                         
   Common            5,000,000            $ 0.001                 $ 5000.00.
</Table>

Shares of stock which the Corporation is authorized to issue may be issued and
Treasury stock may be transferred for such consideration as the directors of the
Corporation (the "Directors") shall determine.

     6.   The Directors are hereby granted full authority to cause the
Corporation to issue one or more classes of stock or one or more series of stock
within any class thereof, any or all of which classes may be of stock with par
value or stock without par value and which classes or series may have such
voting powers, full or limited or no voting powers, and such designations,
preferences and relative, participating optional or other special rights, and
qualifications, limitations or restrictions thereof as shall be stated and
expressed in a resolution or resolutions of the Directors.

     7.   The following provisions for the regulation of the internal affairs of
the Corporation are hereby adopted:

A.   The Bylaws for the governing of the Corporation may be adopted, amended,
     altered, repealed or readopted by the Directors at any regular or special
     meeting of the Directors, but the powers of the Directors will at all times
     be subject to the right of the shareholders to adopt, amend or repeal the
     Bylaws at any annual or special meeting of shareholders, and the power of
     the Directors will not extend to any amendment of the Bylaws respecting the
     number, qualifications or term of office of the Directors.

B.   A quorum of Directors necessary for conducting business shall never be less
     than a majority of the Directors holding office.

C.   A vote of the shareholders of the Corporation as a constituent corporation
     surviving a merger shall be required to authorize a merger notwithstanding
     the fact that the merger meets the conditions of 18 Okla. Stat. Section
     1081 F.

D.   The number of authorized shares of any class or classes of stock may, by
     amendment to the Corporation's Certificate of Incorporation, be increased
     or decreased but not below the number of shares of such class or classes
     then outstanding, by the affirmative vote of

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     the holders of a majority of the stock of the Corporation entitled to vote,
     irrespective of the provisions of 18 Okla. Stat. Section 1077 B. 2.

E.   Each shareholder of the Corporation will be entitled to full preemptive
     rights to subscribe to and purchase such shareholder's proportionate part
     of any shares or securities convertible into shares which might be issued
     at any time by the Corporation after the initial issuance of stock made in
     connection with the formation of the Corporation.

F.   On the request of any person who believes he is entitled to indemnification
     pursuant to the provisions of 18 Okla. Stat. 1031 A. or B., the Directors
     will by vote at a special meeting, immediately called for such purpose,
     determine whether such person has met the standards of conduct set forth in
     18 Okla. Stat. Section 1031 A. or B., whichever is applicable, subject to
     the provisions of 18 Okla. Stat. Section 1031 D.1. and 2., and if so
     provide for such indemnification.

G.   Whenever a compromise or arrangement is proposed between this Corporation
     and its creditors or any class of them and/or between this Corporation and
     its shareholders or any class of them, any court of equitable jurisdiction
     within the State of Oklahoma, on the application in a summary way of this
     Corporation or of any creditor or shareholder thereof or on the application
     of any receiver or receivers appointed for this Corporation under the
     provisions of Section 1106 of the Oklahoma Business Corporation Act (the
     "Act") or on the application of trustees in dissolution or of any receiver
     or receivers appointed for this Corporation under the provisions of Section
     1100 of the Act, may order a meeting of the creditors or class of
     creditors, and/or of the shareholders or class of shareholders of this
     Corporation, as the case may be, to be summoned in such manner as the court
     directs. If a majority in number representing three-fourths (3/4ths) in
     value of the creditors or class of creditors, and/or of the shareholders or
     class of shareholders of this Corporation, as the case may be, agree to any
     compromise or arrangement and to any reorganization of this Corporation as
     a consequence of such compromise or arrangement, the compromise or
     arrangement and the reorganization, if sanctioned by the court to which the
     application has been made, shall be binding on all the creditors or class
     of creditors, and/or on all the shareholders or class of shareholders, of
     this Corporation, as the case may be, and also on this Corporation.

H.   Appraisal rights, as provided for in the Act, including 18 Okla. Stat.
     Section 1091, shall be available for the shares of any class or series of
     the Corporations stock as a result of:

     (i)  any merger or consolidation in which the Corporation is a constituent
          corporation; and

     (ii) the sale of all or substantially all of the assets of the Corporation.

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          THE UNDERSIGNED, for the purpose of forming a corporation pursuant to
the Oklahoma General Corporation Act hereby declare and certify that this is the
act and deed of the undersigned and that the facts herein stated are true, as of
this ID day of December, 1996.



                                                    /s/ James E. Britton
                                              ----------------------------------
                                              James E. Britton


STATE OF OKLAHOMA  )
                   ) SS:
COUNTY OF OKLAHOMA )

          This instrument was acknowledged before me on the 9th day of December,
1996, by James E. Britton.


(SEAL)
                                                    /s/
                                              ----------------------------------
                                              Notary Public
                                              My Commission Expires: 9/7/2000

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