Document:

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                                                                    EXHIBIT 10.4

                               VOTING AGREEMENT

     VOTING AGREEMENT ("Agreement") dated as of December 13, 1999 between
Union Oil Company of California, a California corporation ("Union Oil"), and
Jack D. Hightower (the "Stockholder").

                             W I T N E S S E T H:

     WHEREAS, as of the date hereof, the Stockholder beneficially owns an
aggregate of 4,389,690 shares of Common Stock, par value $.01 per share ("Titan
Common Stock"), of Titan Exploration, Inc., a Delaware corporation ( "Titan")
(such shares of Titan Common Stock and any shares of Titan Common Stock acquired
by the Stockholder after the date hereof, the "Shares");

     WHEREAS, Union Oil is prepared to enter into an Agreement and Plan of
Merger among Titan Resources Holdings, Inc., a Delaware corporation and wholly
owned subsidiary of Union Oil ("Resources"), TRH, Inc., a Delaware corporation
and wholly owned subsidiary of Resources ("Sub"), and Titan (as amended from
time to time, the "Merger Agreement") providing for the merger of Titan with Sub
(the "Merger"), as a result of which Titan will become a wholly owned subsidiary
of Resources;

     WHEREAS, in order to encourage Union Oil, Resources and Sub to enter
into the Merger Agreement with Titan, the Stockholder is willing to enter into
certain arrangements with respect to the Shares;

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

     1.   Stockholder's Support of the Merger. From the date hereof until the
earliest to occur of (i) the termination of the Merger Agreement, and (ii) the
consummation of the Merger:

          (a)  The Stockholder agrees that it will maintain beneficial
     ownership of the Shares and will not, directly or indirectly, (i) sell,
     transfer, pledge or otherwise dispose of any Shares to any person other
     than Union Oil or its designee unless such person shall have agreed in
     writing to be bound by the terms of this Agreement, or (ii) grant a proxy
     with respect to any Shares to any person other than Union Oil or its
     designee, or grant an option
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     with respect to any of the foregoing, or enter into any other agreement or
     arrangement with respect to any of the foregoing.

          (b)  The Stockholder will not initiate, solicit or encourage
     (including by way of furnishing information or assistance), or take any
     other action to facilitate, any inquiries or the making of any proposal
     relating to, or that may reasonably be expected to lead to, any merger,
     consolidation, share exchange, business combination or similar transaction
     involving Titan or any of its subsidiaries or the acquisition in any
     manner, directly or indirectly, of a material equity interest in any voting
     securities of, or a substantial portion of the assets of, Titan or any of
     its Subsidiaries, other than the transactions contemplated by this
     Agreement or the Merger Agreement (a "Competing Transaction"), or enter
     into discussions or negotiate with any person or entity in furtherance of
     such inquiries or to obtain a Competing Transaction, or agree to, or
     endorse, any Competing Transaction, or authorize or permit any investment
     banker, financial advisor, attorney, accountant or other representative
     retained by the Stockholder to take any such action. The Stockholder shall
     promptly notify Union Oil of all relevant terms of any such inquiries or
     proposals received by the Stockholder or by any such investment banker,
     financial advisor, attorney, accountant or other representative relating to
     any of such matters and if such inquiry or proposal is in writing, the
     Stockholder shall deliver or cause to be delivered to Union Oil a copy of
     such inquiry or proposal.

          (c)  The Stockholder agrees that it will vote all Shares (i) in favor
     of approval of the Merger Agreement and any other matters that are
     conditions to consummation of the Merger and (ii) subject to the provisions
     of paragraph (d) below, against any combination proposal or other matter
     that may interfere or be inconsistent with the Merger (including without
     limitation a Competing Transaction).

          (d)  The Stockholder agrees that, if requested by Union Oil, the
     Stockholder will not attend and the Stockholder will not vote the Shares at
     any annual or special meeting of stockholders at which a Competing
     Transaction is being considered, or execute any written consent of
     stockholders relating directly or indirectly to a Competing Transaction,
     during such period.

          (e)  The Stockholder acknowledges that the terms of this Agreement
     will be required to be described, and this Agreement will be required to be
     filed, in certain securities law filings relating to the Merger.

          (f)  To the extent inconsistent with the provisions of this Section 1,
     the Stockholder hereby revokes any and all proxies with respect to the
     Shares or any other voting securities of Titan held by the Stockholder.

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     Notwithstanding anything to the contrary set forth herein, this Agreement
shall not restrict the Stockholder from acting in accordance with his fiduciary
duties as an officer or director of Titan.

     In addition, this Agreement shall not be effective with respect to such
number of Shares, if any, as shall be necessary so that none of the entry into
this Agreement or the existence of this Agreement or the rights of Union Oil
hereunder would cause Union Oil or any of its Affiliates to be deemed to be an
"Acquiring Person" within the meaning of the Rights Agreement dated as of June
10, 1999 between Titan and First Union National Bank, as such Rights Agreement
shall be amended from time to time.

     2.   Miscellaneous

          (a)  The Stockholder, on the one hand, and Union Oil, on the other,
     acknowledge and agree that irreparable damage would occur if any of the
     provisions of this Agreement were not performed in accordance with their
     specific terms or were otherwise breached. It is accordingly agreed that
     the parties shall be entitled to an injunction or injunctions to prevent
     breaches of the provisions 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, in addition to any other stockholder to
     which they may be entitled at law or equity.

          (b)  Descriptive headings are for convenience only and shall not
     control or affect the meaning or construction of any provision of this
     Agreement.

          (c)  All notices, consents, requests, instructions, approvals and
     other communications provided for herein shall be validly given, made or
     served, if in writing and delivered personally, by telecopy or sent by
     registered mail, postage prepaid:

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          If to Union Oil:

               Union Oil Company of California
               One Sugar Creek Place
               14141 Southwest Freeway
               Sugar Land, Texas 77478
               Attention: Mr. Phil Ballard
               Facsimile No.: (281) 287-5170

          with a copy to:

               Union Oil Company of California
               2141 Rosecrans Avenue, Suite 4000
               El Segundo, California 90245
               Attention: (1) General Counsel, and
                          (2) Vice President, Corporate Development
               Fax No: (310) 726-7819

          If to the Stockholder:

               Titan Resources Holdings, Inc.
               500 West Texas
               Suite 200
               Midland, Texas 79701
               Attention: Jack D. Hightower
               Fax: (915) 687-3863

     or to such other address or telecopy number as any party may, from time to
     time, designate in a written notice given in a like manner. Notice given by
     telecopy shall be deemed delivered on the day the sender receives telecopy
     confirmation that such notice was received at the telecopy number of the
     addressee. Notice given by mail as set out above shall be deemed delivered
     three days after the date the same is postmarked.

          (d)  From and after the termination of this Agreement, the covenants
     of the parties set forth herein shall be of no further force or effect and
     the parties shall be under no further obligation with respect thereto.

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          (e)  Definitions. For purposes of this Agreement, the following terms
     shall have the following meanings:

               (i)   Merger. "Merger" shall mean the transaction referred to in
          the second whereas clause of this Agreement, or any amendment to or
          modification that does not adversely affect the economic value of the
          Merger to the Stockholder pursuant to the transaction set forth in the
          Merger Agreement.

               (ii)  Person. A "person" shall mean any individual, firm,
          corporation, partnership, trust, limited liability company or other
          entity.

          (f)  Due Authorization; No Conflicts. The Stockholder hereby
     represents and warrants to Union Oil as follows: the Stockholder has full
     power and authority to enter into this Agreement. Neither the execution or
     delivery of this Agreement nor the consummation of the transactions
     contemplated herein will (a) conflict with or result in a breach, default
     or violation of any agreement, proxy, document, instrument, judgment,
     decree, order, governmental permit, certificate, license, law, statute,
     rule or regulation to which the Stockholder is a party or to which it is
     subject, (b) result in the creation of any lien, charge or other
     encumbrance on any Shares or (c) require the Stockholder to obtain the
     consent of any private non-governmental third party. No consent, action,
     approval or authorization of, or registration, declaration or filing with,
     any governmental department, commission, agency or other instrumentality or
     any other person or entity is required to authorize, or is otherwise
     required in connection with, the execution and delivery of this Agreement
     or the Stockholder's performance of the terms of this Agreement or the
     validity or enforceability of this Agreement.

          (g)  Successors and Assigns. This Agreement shall be binding upon, and
     inure to the benefit of, the parties hereto and their respective heirs,
     personal representatives, successors and assigns, but, except as
     contemplated pursuant to paragraph 1(a), shall not be assignable by any
     party hereto without the prior written consent of the other parties hereto.

          (h)  Waiver. No party may waive any of the terms or conditions of this
     Agreement except by a duly signed writing referring to the specific
     provision to be waived.

          (i)  Governing Law. This Agreement shall be governed by, and construed
     and enforced in accordance with, the laws of the State of Delaware.

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          (j)  Entire Agreement. This Agreement constitutes the entire
     agreement, and supersedes all other and prior agreements and
     understandings, both written and oral, among the parties hereto.

          (k)  Counterparts. This Agreement may be executed in two or more
     counterparts, each of which shall be deemed an original but all of which
     shall constitute one and the same instrument.

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     IN WITNESS WHEREOF, the Stockholder and Union Oil have each caused this
Agreement to be duly executed as of the day and year first above written.

                                        UNION OIL COMPANY OF CALIFORNIA

                                        By: /s/ Timothy H. Ling
                                           -----------------------------
                                           Timothy H. Ling
                                           Executive Vice President, North
                                           American Energy Operations and Chief
                                           Financial Officer

                                        JACK D. HIGHTOWER

                                        /s/ Jack D. Hightower
                                        --------------------------------
                                        Jack D. Hightower
                                        President and Chief Executive Officer

                                       7<PAGE>

                                                                    Exhibit 10.8

                            Titan Resources I, Inc.
                                   [Address]

                                    [Date]
[Executive Officer of Titan]

Dear ________:

     You ("Officer") and Titan Resources I, Inc. ("Resources") are parties to
that certain Officer Severance and Retention Bonus Agreement (the "Severance
Agreement") dated June 10, 1999, which provides you with certain compensation
and benefit arrangements upon a "Change of Control" (as defined in the Severance
Agreement) of Resources' parent, Titan Exploration, Inc. ("Titan").

     As you know, Titan has signed an Agreement and Plan of Merger (the "Merger
Agreement") dated December 13, 1999 with Union Oil Company of California, Titan
Resources Holdings, Inc. (the "Company") and TRH, Inc., pursuant to which Titan
will become a wholly-owned subsidiary of the Company.  The transactions
contemplated in the Merger Agreement (the "Merger") will constitute a "Change of
Control" under the Severance Agreement.  You are willing to enter into this
letter agreement in order to resolve any uncertainties and ensure that you
receive the Severance Payment (as defined below) at the closing of the Merger.

     In consideration the promises, covenants and obligations contained herein,
notwithstanding anything to the contrary in the Severance Agreement, Officer and
Resources agree as follows:

     1.   Severance Payment and Release.  On the closing date of the Merger, if
it occurs:

     (a)  Officer shall execute and deliver to Resources the General Release
("General Release") attached hereto as Exhibit A; and

     (b)  Resources shall pay to Officer $___________ (the "Severance Payment"),
which shall constitute the "Payment" as that term is used in the General
Release.  Notwithstanding the foregoing, in the event Officer has any
outstanding indebtedness (the "Indebtedness") to Resources or Titan on the
closing date of the Merger, the Severance Payment shall be paid as follows:

          (i)    to Officer, upon execution of the General Release, to pay any
                 federal income and excise taxes and any related payroll tax
                 obligations of Officer as a result of the Payment;

          (ii)   to Titan, to the extent necessary, to repay the Indebtedness;
                 and
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[Executive]
[Date]
Page 2

          (iii)  after the repayment of the Indebtedness referred to in clause
                 (ii) above, the remaining portion of the Severance Payment, if
                 any, will be paid to Officer.

     2.   No Consummation of Merger.  If the stockholders of Titan approve the
Merger Agreement and the Merger is consummated, a "Change of Control" under the
Severance Agreement will occur.  Officer agrees that in the event the Merger
does not occur, neither the execution of the Merger Agreement nor the approval
of the Merger Agreement by the Titan stockholders shall constitute a "Change of
Control" under the Severance Agreement or otherwise entitle the Officer to any
other benefit thereunder.

     3.   Entire Agreement/Severability.  This letter agreement and the
Severance Agreement constitute the entire agreement between the parties with
respect to the subject matter hereto and may not be modified or amended in any
way except as agreed in writing by both parties.  In the event that any of the
provisions contained in this letter agreement shall be determined to be invalid,
illegal or unenforceable in any respect, the remaining portions of this letter
agreement shall continue in full force and effect.

     4.   Binding Agreement; Assignment.  This letter agreement shall be binding
upon and inure to the benefit of the parties hereto and their respective
successors, heirs and permitted assigns. Neither this letter agreement nor any
of the rights, interests, or obligations hereunder shall be assigned by either
of the parties hereto without the prior written consent of the other party.

     5.   Third Party Rights.  Except for Titan, which the parties expressly
agree is a third party beneficiary with respect to this letter agreement,
nothing in this letter agreement, express or implied, is intended to or shall
confer upon any person other than the parties hereto, and their respective
successors and permitted assigns, any rights, benefits, or remedies of any
nature whatsoever under or by reason of this letter agreement.

     Please confirm your agreement with the foregoing by signing and returning
one copy of this letter agreement to the undersigned, whereupon this letter
agreement shall become a binding agreement between you and Resources.

                                    Very truly yours,

                                    TITAN RESOURCES I, INC.

                                    By:_____________________________________
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[Executive]
[Date]
Page 3

Accepted and agreed as of
the date first written above:

______________________________________
[Executive]
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                                                                       EXHIBIT A
                                                                       ---------

                           GENERAL RELEASE AGREEMENT
                           -------------------------

1.   GENERAL RELEASE OF CLAIMS UNDER AGE DISCRIMINATION IN EMPLOYMENT ACT. In
consideration of the Severance or Retention Bonus Payment ("Payment") to be made
to me under the Officer Severance and Retention Bonus Agreement (the
"Agreement"), I hereby release, acquit, and forever discharge (i) Titan
Resources I, Inc. and any parent, subsidiary, affiliated entity, successors or
assigns (the "Company"), and (ii) the stockholders, officers, directors,
employees, agents, representatives, and fiduciaries of the Company (collectively
the "Released Parties"), from any and all claims, liabilities, demands, and
causes of action of whatever kind or character, whether vicarious, derivative,
or direct, that I now have or claim against them arising under the Age
Discrimination in Employment Act.  This General Release does not waive rights or
claims that may arise after the date this General Release is executed. Further
in consideration of the Payment to be made to me under the Agreement, I
acknowledge and agree that the Released Parties may recover from me any loss,
including attorney's fees and costs of defending against any claim brought by
me, they may incur arising out of my breach of this General Release.

     I understand that I may revoke my acceptance of paragraph 1 of this
General Release by so notifying the Company within seven days of the date I
execute this General Release.  I further understand that if I do not timely
revoke my acceptance of paragraph 1, paragraph 1 of this General Release is
final and binding, and I agree not to challenge its enforceability.  If I do
challenge its enforceability, I agree initially to tender to the Company the
Payment made under the Agreement, and invite the Company to retain such money
and agree with me to cancel this General Release.  In the event the Company
accepts my offer, the Company shall retain such money and paragraph 1 of this
General Release will be void.  In the event the Company does not accept my
offer, the Company shall place such money in an escrow account pending the
resolution of any dispute as to whether paragraph 1 of this General Release
shall be set aside and/or otherwise rendered unenforceable.

2.   GENERAL RELEASE OF CLAIMS OTHER THAN UNDER AGE DISCRIMINATION IN EMPLOYMENT
ACT.  In consideration of the Payment to be made to me under the Agreement, I
hereby release, acquit, and forever discharge (i) the Company, and (ii) the
Released Parties, from any and all claims, liabilities, demands, and causes of
action of whatever kind or character, whether vicarious, derivative, or direct,
that I now have or claim against them connected in any way to the Agreement or
any claim for benefits under the Agreement (other than as described in Paragraph
3 below), or my employment, continuation of employment, or, if applicable,
termination of employment with any of the Released Parties, or with any other
act, conduct, or omission of any of the Released Parties, including but not
limited to claims arising under any federal, state, or local laws relating to
the employment relationship, other than claims, liabilities, demands, and causes
of action under the Age Discrimination in Employment Act.  This General Release
does not waive rights or claims that may arise after the date this General
Release is executed. Further in consideration of the Payment to be made to me
under the Agreement, I acknowledge and agree that the Released Parties may
recover from me any loss, including attorney's fees and costs of defending
against any claim brought by me, they may incur arising out of my breach of this
General Release.

3.   NO RELEASE OF COMPANY'S OBLIGATION TO MAKE TAX GROSS-UP PAYMENT UNDER THE
AGREEMENT.  Any provision of this General Release or the Letter Agreement
between
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the Company and myself dated of even date herewith to the contrary
notwithstanding, my execution of this General Release does not constitute a
release of the Company's obligation under the Agreement to make additional
payments to me if it shall be determined that I am subject to additional excise
tax under Section 4999 of the Internal Revenue Code of 1986, as amended, as a
result of any payments made or benefits provided to me pursuant to the Agreement
or otherwise in connection with a Change of Control (as defined in the
Agreement).

     I understand that I may not revoke my acceptance of paragraph 2 of this
General Release and that it is binding upon me whether or not I revoke my
acceptance of paragraph 1 of this General Release.

     I have read and fully understand all of the provisions of this General
Release.  I acknowledge that none of the Released Parties has made any promise
or representation to me in consideration for my agreement to execute this
General Release that is not set out in this General Release, and that in
executing this General Release I am not relying on any such promise or
representation but instead am relying solely on my own judgment.  I further
acknowledge that my execution of this General Release is knowing and voluntary,
that I have had a reasonable time to consider its terms, and that I have been
advised to consult with an attorney about this General Release.

Date signed:________________________     _______________________________________
                                         Signature of Employee

Date signed:________________________     _______________________________________
                                         Witness

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