<PAGE>
                                                                   EXHIBIT 10.52

                       VOTING AND DISPOSITION AGREEMENT

          This VOTING AND DISPOSITION AGREEMENT, dated as of July 13, 2000 (this
"Agreement"), by and among Hanover Compressor Company, a Delaware corporation
("Parent"), and the undersigned holders (collectively, the "Holders" and each a
"Holder") of shares of common stock, par value $.01 per share ("Company Common
Stock"), of OEC Compression Corporation, an Oklahoma corporation (the
"Company").

                                    RECITALS

          WHEREAS, the Company, Parent and Caddo Acquisition Corporation, an
Oklahoma corporation and a wholly-owned subsidiary of Parent ("Merger Sub"),
propose to enter into an Agreement and Plan of Merger dated as of the date
hereof (the "Merger Agreement"; capitalized terms used and not defined herein
having the meanings given them in the Merger Agreement), pursuant to which
Merger Sub would be merged with and into the Company (the "Merger"), and each
outstanding share of Company Common Stock would be converted into the right to
receive shares of common stock, par value $.001 per share, of Parent ("Parent
Common Stock");

          WHEREAS, as a condition of its entering into the Merger Agreement,
Parent has requested each Holder to agree, and each Holder hereby agrees, to
enter into this Agreement;

          WHEREAS, prior to the date hereof, Parent and the Holders had no
agreement, arrangement or understanding (as such terms are used in Section
1090.3 of the Oklahoma General Corporation Law (the "OGCL")) for the purpose of
acquiring, holding, voting or disposing of shares of Company Common Stock; and

          WHEREAS, in consideration for the agreements contained herein, prior
to the execution hereof, and prior to Parent becoming an "interested
stockholder" for purposes of Section 1090.3 of the OGCL, the Board of Directors
of the Company has approved this Agreement, the Merger Agreement and the
transactions contemplated hereby and thereby, including the agreement of the
Holders to vote as provided in Section 2 of this Agreement and not to transfer
shares of Company Common Stock as provided in Section 6(B) of this Agreement.

                                   AGREEMENT

          NOW, THEREFORE, the parties hereto agree as follows:

        1  Representations and Warranties of the Holders. Each Holder represents
and warrants, severally and not jointly, to Parent as follows:

                A. Ownership of Securities. As of the date hereof, such Holder
        is the record and/or beneficial owner of the number of shares of Company
        Common Stock (the "Existing Securities") (together with any shares of
        Company Common Stock or other securities, of the Company hereafter
        acquired by the Holder through purchase, exercise of
<PAGE>

        options or warrants or otherwise, the "Subject Securities") set forth on
        the signature page to this Agreement. Such Holder does not beneficially
        or of record own any securities of the Company on the date hereof other
        than the Existing Securities. Such Holder has sole voting power and sole
        power to issue instructions with respect to the voting of the Existing
        Securities, sole power of disposition, sole power of exercise and the
        sole power to demand appraisal rights, in each case with respect to all
        of the Existing Securities, and, on the date of the Company
        Stockholders' Meeting (as defined in the Merger Agreement), will have
        the sole voting power and power to issue instructions with respect to
        the voting of all of such Holder's Subject Securities, the sole powers
        of disposition, exercise and the sole power to demand appraisal rights,
        in each case with respect to all of such Holder's Subject Securities.

                B. Authority; Binding Agreement. Each Holder has the legal
        capacity, power and authority to enter into and perform all of such
        Holder's obligations under this Agreement. The execution, delivery and
        performance of this Agreement by each Holder will not violate any other
        agreement relating to the Subject Securities to which the Holder is a
        party, including, without limitation, any voting agreement,
        stockholder's agreement, partnership agreement or voting trust. This
        Agreement has been duly and validly executed and delivered by such
        Holder and constitutes a valid and binding agreement of such Holder,
        enforceable against such Holder in accordance with its terms, except
        that (i) such enforcement may be subject to applicable bankruptcy,
        insolvency or other similar laws, now or hereafter in effect, affecting
        creditors' rights generally, and (ii) the remedy of specific performance
        and injunctive and other forms of equitable relief may be subject to
        equitable defenses and to the discretion of the court before which any
        proceeding therefor may be brought.

                C. No Conflicts. No filing with, and no permit, authorization,
        consent or approval of, any local, state or federal public body or
        authority is necessary for the execution of this Agreement by such
        Holder and the consummation by such Holder of the transactions
        contemplated hereby, and neither the execution and delivery of this
        Agreement by such Holder, nor the consummation by such Holder of the
        transactions contemplated hereby nor compliance by such Holder with any
        of the provisions hereof shall conflict with or result in any breach of
        any applicable corporate, partnership or other organizational documents
        applicable to such Holder, result in a violation or breach of, or
        constitute (with or without notice or lapse of time or both) a default
        (or give rise to any third-party right of termination, cancellation,
        material modification or acceleration) under any of the terms,
        conditions or provisions of any note, bond, mortgage, indenture,
        license, contract, commitment, arrangement, understanding, agreement or
        other instrument or obligation of any kind to which such Holder is a
        party or by which such Holder's properties or assets may be bound or
        violate any order, writ, injunction, decree, judgment, statute, rule or
        regulation applicable to such Holder or any of such Holder's properties
        or assets.

                D. No Encumbrances. The Subject Securities are now, and at all
        times during the term hereof will be, held by such Holder, or by a
        nominee or custodian for the benefit

                                       2
<PAGE>

        of such Holder, free and clear of all liens, claims, options, charges,
        security interests, proxies, voting trusts or agreements, understandings
        or arrangements or any other encumbrances or proxies whatsoever
        (collectively, "Encumbrances"), except for any encumbrances or proxies
        arising hereunder.

                E. No Finder's Fees. No broker, investment banker, financial
        advisor or other Person (as defined below) is entitled to any broker's,
        finder's, financial advisor's or other similar fee or commission in
        connection with the transactions contemplated hereby based upon
        arrangements made by or on behalf of the Holder except that the Company
        has employed Prudential Securities as its financial advisor, the
        arrangements with which have been disclosed in writing to Parent and
        Merger Sub prior to, and will not be modified subsequent to, the date of
        the Merger Agreement. "Person" shall mean any individual, corporation,
        partnership, limited liability company, sole proprietorship, trust,
        joint venture, firm, association, company or other entity.

                F. No Other Agreements. Except pursuant to the Merger Agreement,
        no Holder has a legal obligation, absolute or contingent, to any other
        Person to sell, dispose of or otherwise transfer all or any portion of
        the Subject Securities.

                G. Reliance by Parent. The Holders understand and acknowledge
        that Parent is entering into, and causing Merger Sub to enter into, the
        Merger Agreement in reliance upon the Holder's execution, delivery and
        performance of this Agreement.

        2  Agreement to Vote Shares. During the period commencing on the date
hereof and continuing until the first to occur of (i) the Effective Time and
(ii) the termination of the Merger Agreement, at every meeting of the
stockholders of the Company however called and at every adjournment thereof, and
on every action or approval by written consent of the stockholders of the
Company with respect to any of the following, each Holder, severally and not
jointly, agrees that it shall vote (or caused to be voted), or execute a written
consent with respect to, as appropriate, all of the Subject Securities as to
which it has power to vote in any such vote or consent: (i) in favor of the
Merger, the adoption of and execution and delivery by the Company of the Merger
Agreement and the approval of the terms thereof and each of the other
transactions contemplated by the Merger Agreement and (ii) against the following
actions (other than the Merger and the transactions contemplated by the Merger
Agreement): (1) any merger, consolidation, business combination,
recapitalization, sale of substantial assets, sale or acquisition of shares of
capital stock (including, without limitation, by way of a tender offer) or
similar transaction involving the Company or any of its subsidiaries; (2) (a)
any amendment of the Company's certificate of incorporation or bylaws or any
change in the majority of the Board of Directors of the Company; (b) any
material change in the present capitalization of the Company; (c) any other
material change in the Company's corporate structure or business; or (d) any
other action, which, in the case of each of the matters referred to in clauses
(a), (b) or (c) above, is intended, or could reasonably be expected, to impede,
interfere with, delay, postpone, discourage or materially adversely affect the
consummation of the Merger or the transactions contemplated by the Merger
Agreement or this Agreement; and (3) any action or agreement that would result
in a breach in any respect of any covenant, representation or warranty or any
other

                                       3
<PAGE>

obligation or agreement of the Company under the Merger Agreement or of a Holder
under this Agreement.

        3  IRREVOCABLE PROXY. EACH HOLDER HEREBY, SEVERALLY AND NOT JOINTLY,
GRANTS TO, AND APPOINTS MERGER SUB AND THE PRESIDENT OF MERGER SUB AND THE
TREASURER OF MERGER SUB, IN THEIR RESPECTIVE CAPACITIES AS OFFICERS OF MERGER
SUB, AND ANY INDIVIDUAL WHO SHALL HEREAFTER SUCCEED TO ANY SUCH OFFICE OF MERGER
SUB, AND ANY OTHER DESIGNEE OF MERGER SUB, EACH OF THEM INDIVIDUALLY, SUCH
HOLDER'S PROXY WITH RESPECT TO THE SUBJECT SECURITIES AND ATTORNEY-IN-FACT (WITH
FULL POWER OF SUBSTITUTION) TO VOTE OR ACT BY WRITTEN CONSENT WITH RESPECT TO
SUCH HOLDER'S SUBJECT SECURITIES IN ACCORDANCE WITH SECTION 2 HEREOF. THIS PROXY
IS COUPLED WITH AN INTEREST AND SHALL BE IRREVOCABLE. EACH HOLDER WILL TAKE SUCH
FURTHER ACTION OR EXECUTE SUCH OTHER INSTRUMENTS, INCLUDING, WITHOUT LIMITATION,
THE FORM OF PROXY ATTACHED HERETO AS EXHIBIT A (THE "PROXY") AS MAY BE
REASONABLY NECESSARY TO EFFECTUATE THE INTENT OF THIS PROXY AND HEREBY REVOKES
ANY PROXY PREVIOUSLY GRANTED BY IT WITH RESPECT TO THE SUBJECT SECURITIES. AS
PROMPTLY AS PRACTICABLE, EACH HOLDER SHALL MAKE ALL FILINGS AND GIVE ALL NOTICES
WITH RESPECT TO THE PROXY AS MAY BE REQUIRED BY APPLICABLE LAW. THE HOLDER SHALL
NOT ENTER INTO ANY AGREEMENT OR UNDERSTANDING WITH ANY PERSON, THE EFFECT OF
WHICH WOULD BE INCONSISTENT WITH, OR VIOLATIVE OF, THE PROVISIONS AND AGREEMENTS
CONTAINED IN THIS SECTION 3.

        4  Restrictions on Transfer of Parent Common Stock. Each of the Holders,
hereby agree that such Holder shall not, directly or indirectly, during a period
of 120 days from the Effective Time (the "Standstill Period"), without the prior
written consent of Parent, sell, offer or agree to sell or otherwise dispose of
any Parent Common Stock received by such Holder pursuant to the Merger. Each
Holder further agrees that, for each succeeding 30-day period following the
Standstill Period, such Holder shall not, directly or indirectly, without the
written consent of Parent, sell, offer or agree to sell or otherwise dispose of,
more than 15% of the shares of Parent Common Stock such Holder receives in
connection with the Merger. Each Holder acknowledges and agrees that the
certificates representing such Holder's Parent Common Stock will bear a legend
in substantially the following form:

     THE SECURITIES REPRESENTED BY THIS CERTIFICATE ARE SUBJECT TO CERTAIN
     RESTRICTIONS ON TRANSFER SET FORTH IN THAT CERTAIN VOTING AND DISPOSITION
     AGREEMENT DATED AS OF JULY __, 2000 BY AND AMONG THE RESTRICTED HOLDERS (AS
     DEFINED THEREIN), HANOVER COMPRESSOR COMPANY AND CADDO ACQUISITION
     CORPORATION.

                                       4
<PAGE>

5.  Representations and Warranties of Parent.

        A. Power; Binding Agreement. Parent has full corporate power and
authority to enter into and perform all of Parent's obligations under this
Agreement. This Agreement has been duly and validly executed and delivered by
Parent and constitutes a valid and binding agreement of Parent, enforceable
against Parent in accordance with its terms, except that (i) such enforcement
may be subject to applicable bankruptcy, insolvency or other similar laws, now
or hereafter in effect, affecting creditors' rights generally, and (ii) the
remedy of specific performance and injunctive and other forms of equitable
relief may be subject to equitable defenses and to the discretion of the court
before which any proceeding therefor may be brought.

        B. No Conflicts. No filing with, and no permit, authorization, consent
or approval of, any state or federal public body or authority is necessary for
the execution of this Agreement by Parent and the consummation by Parent of the
transactions contemplated hereby and neither the execution and delivery of this
Agreement by Parent nor the consummation by Parent of the transactions
contemplated hereby, nor compliance by Parent with any of the provisions hereof
shall conflict with or result in any breach of any organizational documents
applicable to Parent, or result in a violation or breach of, or constitute (with
or without notice or lapse of time or both) a default, or give rise to any
third-party right of termination, cancellation, material modification or
acceleration under any of the terms, conditions or provisions of any note, bond,
mortgage, indenture, license, contract, commitment, arrangement, understanding,
agreement or other instrument or obligation of any kind to which Parent is a
party or by which Parent's properties or assets may be bound, or violate any
order, writ, injunction, decree, judgment, statute, rule or regulation
applicable to Parent or any of Parent's properties or assets, except for any
such conflicts, breaches, defaults or violations as would not materially impair
Parent's performance of its obligations hereunder.

     6  Covenants of the Holders.  Each Holder, severally and not jointly,
hereby agrees and covenants that:

          A.  No Solicitation.  Such Holder (and Persons acting on behalf of the
     Holder) shall not, directly or indirectly, solicit (including by way of
     furnishing information), initiate, encourage or respond to, or take any
     other action knowingly to facilitate any inquiries or the making of any
     proposal by any Person with respect to the Company that constitutes, or
     could reasonably be expected to lead to, an Acquisition Proposal or permit
     or authorize any Person acting on behalf of the Holder to do any of the
     foregoing.  If any Holder receives any such inquiry or proposal, then it
     shall immediately inform Parent of all terms and conditions, if any, of
     such inquiry or proposal and the identity of the person making it and
     shall, in the case of written proposals or inquiries, furnish Parent with a
     copy of such proposal or inquiry (and all amendments and supplements
     thereto).  Such Holder will immediately cease and cause to be terminated
     any existing activities, discussions or negotiations with any parties
     conducted heretofore with respect to any of the foregoing.

                                       5
<PAGE>

          B.  Restriction on Transfer of Company Common Stock, Proxies and
     Noninterference.  Such Holder shall not, prior to the termination of this
     Agreement, directly or indirectly, except pursuant to the terms of the
     Merger Agreement or this Agreement: (i) offer for sale, sell, transfer
     (whether by merger, operation of law or otherwise), tender, pledge,
     encumber, assign or otherwise dispose of, or enter into any contract,
     option or other arrangement or understanding with respect to or consent to
     the offer for sale, sale, transfer, tender, pledge, encumbrance, assignment
     or other disposition of, any or all of such Holder's Subject Securities;
     (ii) grant any proxies or powers of attorney, deposit any such Subject
     Securities into a voting trust or enter into a voting agreement with
     respect to any of such Holder's Subject Securities; or (iii) take any
     action that would make any representation, warranty, covenant or other
     provision contained herein untrue or incorrect or have the effect of, or
     could reasonably be expected to, impede, interfere with, delay, postpone,
     discourage or materially adversely affect such Holder from performing its
     obligations under this Agreement.  The Holder's Company Common Stock
     certificates shall be legended to reflect the above restrictions.

        C.  Waiver of Appraisal Rights. Such Holder hereby irrevocably waives
any rights of appraisal or rights to dissent, if any, from the Merger that the
Holder may now or hereafter have.

        D.  Stop Transfer; Changes in Subject Securities. Such Holder shall not
request that the Company register the transfer (book-entry or otherwise) of any
certificate or uncertificated interest representing any of the Subject
Securities, unless such transfer is made in compliance with this Agreement. In
the event of a stock dividend or distribution, or any change in the Company
Common Stock by reason of any stock dividend, split-up, merger,
recapitalization, combination, conversion or exchange of shares or the like (in
each case with a record date prior to the termination of this Agreement), the
term "Subject Securities" shall be deemed to refer to and include the Subject
Securities as well as all such stock dividends and distributions and any
securities into which or for which any or all of the Subject Securities may be
changed or exchanged and such dividends, distributions and securities, as the
case may be, shall be paid to Parent at the Closing or promptly following the
receipt of such dividend or distribution, if the Closing theretofor shall have
occurred.

        E.  Confidentiality. Such Holder recognizes that successful consummation
of the transactions contemplated by this Agreement and the Merger Agreement may
be dependent upon confidentiality with respect to the matters referred to
herein. In this connection, pending public disclosure thereof in accordance with
the provisions of the Merger Agreement, the Holder hereby agrees not to disclose
or discuss such matters with any Person (other than Parent or Merger Sub and the
respective counsel and advisors of the Holders, Parent and Merger Sub) without
the prior written consent of Parent, except for filings required pursuant to the
Exchange Act and the rules and regulations thereunder or disclosures necessary
in order to fulfill the Holder's obligations imposed by law, in which event the
Holder shall give prior written notice of such disclosure to Parent as

                                       6
<PAGE>

promptly as practicable so as to enable Parent to seek a protective order from a
court of competent jurisdiction with respect thereto.

     7  Fiduciary Duties.  Notwithstanding anything in this Agreement to the
contrary, the covenants and agreements set forth herein shall not prevent any
Holders serving on the Company's Board of Directors from taking any action,
subject to applicable provisions of the Merger Agreement, which such director
shall determine in good faith, after consultation with legal counsel, to be
required by his fiduciary duties to the Company or its stockholders while acting
in such person's capacity as a director of the Company.

     8  Assignment; Benefits.  This Agreement may be assigned, in whole or in
part, by Parent to Merger Sub or any other wholly-owned subsidiary of Parent, to
the extent and for so long as such subsidiary remains a wholly-owned subsidiary
of Parent.  Other than as permitted in the preceding sentence, this Agreement
may not be assigned by any party hereto without the prior written consent of the
other party.  This Agreement shall be binding upon, and shall inure to the
benefit of, the Holder, Parent and their respective successors and permitted
assigns.

     9  Notices.  All notices and other communications hereunder shall be in
writing and shall be deemed given if delivered personally, telecopied (which is
confirmed) or mailed by registered or certified mail (return receipt requested)
to the parties at the following addresses (or at such other address for a party
as shall be specified by like notice):

                (a)  if to a Holder, to:

                The corresponding address set forth on the signature pages
        hereto;

                (b)  if to Parent, to:

                    Hanover Compressor Company
                    12001 N. Houston Rosslyn Road
                    Houston, Texas 77086
                    Attention:  Michael J. McGhan
                    Telecopy:  (281) 447-0821

                    with a copy to:

                    Latham & Watkins
                    233 South Wacker Drive
                    Suite 5800
                    Chicago, Illinois 60606
                    Attention:  Richard Meller, Esq.
                    Telecopy:  (312) 993-9767

     10  Specific Performance.  The parties hereto agree that irreparable harm
would occur in the event that any of the provisions of this Agreement were not
performed in accordance with its specific terms or were otherwise breached.  It
is accordingly agreed that the parties shall be

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<PAGE>

entitled to an injunction or injunctions to prevent breaches of this Agreement
and to enforce specifically the terms and provisions hereof in any court of the
United States or any state thereof having jurisdiction, this being in addition
to any other remedy to which they are entitled at law or in equity.

     11  Amendment.  This Agreement may not be amended or modified, except by an
instrument in writing signed by or on behalf of each of the parties hereto.
This Agreement may not be waived by either party hereto, except by an instrument
in writing signed by or on behalf of the party granting such waiver.

     12  Governing Law.  The laws of the State of Oklahoma shall govern the
interpretation, validity and performance of the terms of this Agreement,
regardless of the law that might be applied under principles of conflicts of
law. Any suit, action or proceeding by a party hereto with respect to this
Agreement, or any judgment entered by any court in respect of any thereof, may
be brought in any state or federal court of competent jurisdiction in Houston,
Texas and each party hereto hereby submits to the exclusive jurisdiction of such
courts for the purpose of any such suit, action, proceeding or judgment.  Each
party hereto hereby irrevocably waives any objections which it may now or
hereafter have to the laying of the venue of any suit, action or proceeding
arising out of or relating to this Agreement brought in any state or federal
court of competent jurisdiction in Houston, Texas and hereby further irrevocably
waives any claim that any such suit, action or proceeding brought in any such
court has been brought in any inconvenient forum.  No suit, action or proceeding
against a party hereto with respect to this Agreement may be brought in any
court, domestic or foreign, or before any similar domestic or foreign authority
other than in a court of competent jurisdiction Houston, Texas and each party
hereto hereby irrevocably waives any right which it may otherwise have had to
bring such an action in any other court, domestic or foreign, or before any
similar domestic or foreign authority.

     13  Counterparts.  This Agreement may be executed in two or more
counterparts, all of which shall be considered one and the same agreement and
shall become effective when two or more counterparts have been signed by each of
the parties and delivered to the other parties, it being understood that all
parties need not sign the same counterpart.

     14  Termination.  This Agreement shall terminate upon the earlier of (i)
the Effective Time or (ii) the date of termination of the Merger Agreement. Upon
any termination of this Agreement, this Agreement shall thereupon become void
and of no further force and effect, and there shall be no liability in respect
of this Agreement or of any transactions contemplated hereby or by the Merger
Agreement on the part of any party hereto or any of its directors, officers,
partners, stockholders, employees, agents, advisors, representatives or
affiliates; provided, however, that nothing herein shall relieve any party from
any liability for such party's willful breach of this Agreement; and provided
further that nothing herein shall limit, restrict, impair, amend or otherwise
modify the rights, remedies, obligations or liabilities of any Person under any
other contract or agreement, including, without limitation, the Merger
Agreement.

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<PAGE>

     15  Further Assurances.  From time to time, at the other party's request
and without further consideration, each party hereto shall execute and deliver
such additional documents and take all such further lawful action as may be
necessary or appropriate to consummate and make effective, in the most
expeditious manner practicable, the transactions contemplated by this Agreement.

     16  Entire Agreement; No Third Party Beneficiaries.  This Agreement,
together with the Merger Agreement, constitutes the entire agreement between the
parties hereto with respect to the subject matter hereof and supersedes all
other prior agreements and understandings, both written and oral, between the
parties hereto with respect to the subject matter hereof.  This Agreement is not
intended for the benefit of or intended to confer upon any Person other than the
parties hereto any rights or remedies hereunder.

     17  Certain Events.  Each Holder agrees that this Agreement and the
obligations hereunder shall attach to the Subject Securities and shall be
binding upon any Person to which legal or beneficial ownership of such Subject
Securities shall pass, whether by operation of law or otherwise, including,
without limitation, the Holder's heirs, guardians, administrators or successors.
Notwithstanding any transfer of Subject Securities, the transferor shall remain
liable for the performance of all obligations of the transferor under this
Agreement.

     18  Descriptive Headings.  The descriptive headings used herein are
inserted for convenience of reference only and are not intended to be part of or
to affect the meaning or interpretation of this Agreement.

     19  Severability.  Whenever possible, each provision or portion of any
provision of this Agreement will be interpreted in such manner as to be
effective and valid under applicable law, but if any provision or portion of any
provision of this Agreement is held to be invalid, illegal or unenforceable in
any respect under any applicable law or rule in any jurisdiction, such
invalidity, illegality or unenforceabilty will not affect any other provision or
portion of any provision in such jurisdiction, and this Agreement will be
reformed, construed and enforced in such jurisdiction as if such invalid,
illegal or unenforceable provision or portion of any provision had never been
contained herein.

     20  Remedies Cumulative.  All rights, powers and remedies provided under
this Agreement or otherwise available in respect hereof at law or in equity
shall be cumulative and not alternative, and the exercise of any thereof by
either party hereto shall not preclude the simultaneous or later exercise of any
other such right, power or remedy by such party.

     21  No Waiver.  The failure of either party hereto to exercise any right,
power or remedy provided under this Agreement or otherwise available in respect
hereof at law or in equity, or to insist upon compliance by the other party
hereto with its obligations hereunder, and any custom or practice of the parties
hereto at variance with the terms hereof shall not constitute a waiver by such
party of its or his right to exercise any such or other right, power or remedy
or to demand such compliance.

                           [SIGNATURE PAGE FOLLOWS]

                                       9
<PAGE>

        IN WITNESS WHEREOF, this Agreement has been executed by or on behalf of
each of the parties hereto, all as of the date first above written.

                              HANOVER COMPRESSOR COMPANY

                              By:    ____________________________
                              Its:   ____________________________


                              HOLDERS:


                              HACL, Ltd.
                              By: Six-Dawaco, Inc., its general partner

                              By:    ____________________________
                              Its:   ____________________________
                              Address:  2838 Woodside
                                        Dallas, Texas  75201
                              Telecopy: (214) 981-0700

                              Energy Investors Joint Venture
                              By: HACL, Ltd., its managing joint venture partner
                              By: Six-Dawaco, Inc., its general partner

                              By:    ____________________________
                              Its:   ____________________________
                              Address:  2838 Woodside
                                        Dallas, Texas  7201
                              Telecopy: (214) 981-0700

                                      B-1
<PAGE>

                                                                       EXHIBIT A

                           FORM OF IRREVOCABLE PROXY

          Pursuant to Section 3 of the Voting and Disposition Agreement, dated
as of July 13, 2000, as the same may be amended from time to time, (the "Voting
Agreement"), between Hanover Compressor Company, a Delaware corporation
("Parent") and the undersigned stockholders (collectively, the "Holders" and
each a "Holder") of shares of common stock, par value $.01 per share ("Company
Common Stock"), of OEC Compression Corporation, an Oklahoma corporation (the
"Company"), the undersigned hereby irrevocably appoint Caddo Acquisition Corp.,
a Delaware corporation and a wholly-owned subsidiary of Parent ("Merger Sub"),
Michael J. McGhan, and William S. Goldberg, and each of them, or any other
designee of Parent or Merger Sub, their attorneys-in-fact and proxies of the
undersigned, each with full power of substitution:

          (a) to attend any meeting (whether annual or special or both) of the
stockholders of the Company, including any adjournment or postponement thereof,
on behalf of the undersigned, and at such meeting, with respect to all shares of
common stock of the Company owned (or beneficially owned) by the undersigned on
the date hereof or acquired hereafter that are entitled to vote at such meeting
or over which the undersigned has voting power (and any and all other shares of
common stock of the Company or other securities issued on or after the date
hereof in respect of any such shares), including, without limitation, the shares
indicated in the last paragraph of this proxy:

                (i) to vote (in person or by proxy) in favor of the approval of
        the plan of merger contained in Agreement and Plan of Merger, dated as
        of July 13, 2000, by and among Parent, Merger Sub and the Company (as
        the same may be amended from time to time, the "Merger Agreement"), and
        in favor of any other action related to the Merger (as defined in the
        Merger Agreement) or in furtherance of the transactions contemplated by
        the Merger Agreement, and otherwise to act with respect to such shares
        as each such attorney and proxy or his or her substitute shall in his or
        her reasonable discretion deem necessary or appropriate for such
        purpose; and

                (ii) to vote (in person or by proxy) against (A) any merger
        agreement or merger (other than the Merger Agreement and the Merger),
        consolidation, liquidation, dissolution, recapitalization,
        reorganization, winding up or other business combination, acquisition or
        sale or other disposition of a material amount of assets or securities,
        tender offer or exchange offer or any other similar transaction
        involving the Company, its securities or any of its material
        subsidiaries or divisions, (B) any action or agreement that would result
        in a breach in any respect of any covenant, representation or warranty
        or any other obligation or agreement of the Company under the Merger
        Agreement or of any Holder under the Voting Agreement, (C) any change in
        the present capitalization of the Company or any amendment of Company's
        articles of incorporation or by-laws, (D) any other material change in
        the Company's corporate structure or business and (E) any other action
        involving the Company or its subsidiaries which is

                                      B-2
<PAGE>

        intended, or could reasonably be expected, to impede, interfere with,
        delay, postpone, or otherwise adversely affect the Merger or any
        transaction contemplated by the Merger Agreement; and

            (b) to execute and deliver one or more consents in writing in lieu
of such meeting or adjournment thereof.

          The undersigned affirms that this proxy is issued in connection with
the Merger Agreement to facilitate the transactions contemplated thereunder and
in consideration of Parent entering into the Merger Agreement and as such is
coupled with an interest and is irrevocable.  This proxy will terminate upon the
termination of the Merger Agreement in accordance with its terms.  For purposes
of this proxy, any written consent shall be deemed delivered to such attorneys
and proxies and their substitutes when delivered to Merger Sub in accordance
with the Merger Agreement, and any written consent shall be deemed delivered to
the Company when delivered to it in accordance with the Merger Agreement.

          By execution and delivery of this proxy to the designees of Merger
Sub, the undersigned (a) confirms that the undersigned has received copies of
the Merger Agreement and the Voting Agreement, and that all other information
deemed necessary by the undersigned concerning the Merger, the Merger Agreement,
the Voting Agreement and the transactions contemplated under any such agreements
or any other matters considered by the undersigned to be relevant to the
undersigned's decision to execute this proxy have been made available to the
undersigned and (b) agrees that the undersigned win not sell, transfer or
otherwise dispose of any Subject Shares (as defined in the Voting Agreement)
prior to the termination of the Voting Agreement.

          All authority herein conferred or agreed to be conferred shall survive
the death, liquidation or incapacity of the undersigned and any obligation of
the undersigned hereunder shall be binding upon the heirs, personal
representatives, successors and assigns of the undersigned.  This proxy revokes
any and all other proxies heretofore granted by the undersigned to vote or
otherwise to act with respect to any of the shares to which this proxy relates.
The undersigned will not give any subsequent proxy (and such proxy if given will
be deemed not to be effective) with respect to such shares that purports to
grant authority within the scope of the authority hereby conferred, except on
the express condition that such proxy shall not be effective unless and until
this proxy shall have terminated in accordance with its terms.  This proxy shall
be governed by the internal laws of the State of Delaware.

                                      B-3
<PAGE>

          As of the date hereof, the undersigned owns or possesses voting power
with respect to _________ shares of common stock, par value $.01 per share, of
the Company, and such shares are entitled to vote with respect the approval by
the stockholders of the Company of the plan of merger set forth in the Merger
Agreement and each of the other transactions contemplated by the Merger
Agreement.



                              By: ____________________________
                                    [HOLDER]

                                      B-4