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                                                                 EXHIBIT 10.23.1

                  MORTGAGE, DEED OF TRUST, SECURITY AGREEMENT,
                FINANCING STATEMENT AND ASSIGNMENT OF PRODUCTION

          (THIS INSTRUMENT CONTAINS AFTER-ACQUIRED PROPERTY PROVISIONS)

                  This Mortgage, Deed of Trust, Security Agreement, Financing
Statement, and Assignment of Production (this "Deed of Trust") is executed
pursuant to the Credit Agreement dated as of as of December 19, 2002, as
amended, by and among F-W OIL EXPLORATION L.L.C., a Delaware limited liability
company (herein, "Mortgagor), PRIMEENERGY CORPORATION, a Delaware corporation
("Prime"), PRIMEENERGY MANAGEMENT CORPORATION, a New York corporation ("PEMC"),
PRIME OPERATING COMPANY, a Texas corporation ("POC"), EASTERN OIL WELL SERVICE
COMPANY, a West Virginia corporation ("Eastern"), EOWS MIDLAND COMPANY, a Texas
corporation ("EOWS") and SOUTHWEST OILFIELD CONSTRUCTION COMPANY, an Oklahoma
corporation ("Southwest") (Mortgagor, Prime, PEMC, POC, Eastern, EOWS, and
Southwest herein collectively, "Borrowers"), and GUARANTY BANK, FSB, a federal
savings bank, individually as a Lender and as Agent for the lenders signatory
thereto from time to time (the "Lenders") (as amended, restated, or supplemented
from time to time, the "Credit Agreement"). Capitalized terms used but not
defined herein shall have the meanings assigned to such terms in the Credit
Agreement.

                  Mortgagor, acting herein by and through its proper officers
who have heretofore been duly authorized, whose mailing address is 9821 Katy
Freeway, Suite 1050, Houston, Texas 77024, hereby agrees as follows:

                                    ARTICLE 1

                                      GRANT

                  1.1 Lien. Mortgagor, for valuable consideration, the receipt
of which is hereby acknowledged, and in consideration of the debt and trust
hereinafter mentioned, has granted, bargained, sold, conveyed, transferred and
assigned, and by these presents does grant, bargain, sell, convey, transfer and
assign to Arthur R. Gralla, Jr., Trustee, whose address is c/o Guaranty Bank,
FSB, 333 Clay Street, Suite 4400, Houston, Texas 77002-4103, and his successors
and substitutes in trust, as hereinafter provided (the "Trustee"), for the
benefit of Guaranty Bank, FSB, as Agent for the lenders, with banking quarters
in Houston, Harris County, Texas, the mailing address for which is 333 Clay
Street, Suite 4400, Houston, Texas 77002-4103 ("Mortgagee"), the following
described Property:

                  (a) all right, title, and interest, whether now owned and
         existing or hereafter acquired or arising, of Mortgagor in and to the
         leases, rights of way, easements, or other documents described in
         Exhibit A attached hereto and incorporated herein for all purposes or
         described or referred to in the documents described in Exhibit A,
         without regard to any surface acreage and/or depth limitations set
         forth in Exhibit A, and all renewals and extensions thereof and all new
         leases, rights of way, easements, or other documents (i) in which an
         interest is acquired by Mortgagor after the termination or expiration
         of any lease, right of way, easement, or

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         other document described or referred to in Exhibit A, and (ii) that
         covers all or any part of the Property described in and covered by such
         terminated or expired lease, right of way, easement, or other document,
         to the extent, and only to the extent, such new leases, rights of way,
         easements, or other documents may cover such Property (all of the
         foregoing in this subsection (a) being the "Leases");

                  (b) all right, title, and interest, whether now owned and
         existing or hereafter acquired or arising, of Mortgagor in and to the
         lands subject to the Leases or otherwise described or referred to in
         Exhibit A, without regard to any surface acreage and/or depth
         limitations set forth in Exhibit A (the "Lands"), including, without
         limitation, the oil, gas, mineral, and leasehold estates in and to the
         Lands;

                  (c) all right, title, and interest, whether now owned and
         existing or hereafter acquired or arising, of Mortgagor in and to any
         of the oil, gas, and minerals in, on, or under the Lands, including,
         without limitation, all contractual rights, fee interests, leasehold
         interests, overriding royalty interests, non-participating royalty
         interests, mineral interests, production payments, net profits
         interests, or any other interest measured by or payable out of
         production of oil, gas, or other minerals from the Leases and/or Lands;

                  (d) all of the foregoing interests of Mortgagor as such
         interests may be enlarged by the discharge of any payments out of
         production or by the removal of any charges or encumbrances;

                  (e) all right, title, and interest, whether now owned and
         existing or hereafter acquired or arising, of Mortgagor in, to, and
         under or derived from any present or future operating, farmout,
         bidding, pooling, unitization, and communitization agreements,
         assignments, and subleases, whether or not described in Exhibit A, to
         the extent, and only to the extent, that such agreements, assignments,
         and subleases cover or include any right, title, and interest, whether
         now owned and existing or hereafter acquired or arising, of Mortgagor
         in and to all or any portion of the Leases and/or the Lands, and all
         units created by any such pooling, unitization, and communitization
         agreements and all units formed under orders, regulations, rules, or
         other official acts of any Governmental Authority having jurisdiction,
         to the extent and only to the extent that such units cover or include
         all or any portion of the Leases and/or the Lands;

                  (f) all right, title, and interest, whether now owned and
         existing or hereafter acquired or arising, of Mortgagor in, to, and
         under or derived from all presently existing and future advance payment
         agreements, oil, casinghead gas, and gas sales, exchange, and
         processing contracts and agreements, including, without limitation,
         those contracts and agreements that are described or referred to in
         Exhibit A, to the extent, and only to the extent, those contracts and
         agreements cover or include all or any portion of the Leases and/or the
         Lands; and

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                (g) all right, title, and interest, whether now owned and
        existing or hereafter acquired or arising, of Mortgagor in, to, and
        under or derived from all existing and future permits, licenses,
        easements, and similar rights and privileges that relate to or are
        appurtenant to any of the Leases and/or the Lands.

                  1.2 Security Interest. Mortgagor, for the same consideration,
hereby grants to Mortgagee a continuing security interest in all improvements
and all personal Property of any kind or character defined in and subject to the
provisions of the Uniform Commercial Code ("UCC"), including, but not limited
to, substitutions and replacements for, accessions to, and the proceeds and
products from any and all of such improvements and personal Property, as well as
any and all "as- extracted collateral" as such term is defined in the UCC,
whether now owned and existing or hereafter acquired or arising, and situated on
any of the Lands, including, but not limited to, pipe, casing, tubing, rods,
storage tanks, boilers, loading racks, pumps, foundations, warehouses, and all
other personal Property and equipment of every kind and character upon,
incident, appurtenant, or belonging to and used in connection with the interest
of Mortgagor, whether now owned and existing or hereafter acquired or arising,
in the Lands and/or the Leases, including all oil, gas, and other minerals
produced or to be produced to the account of Mortgagor from the Lands and all
accounts receivable, general intangibles, and contract rights of Mortgagor in
connection with the Lands and/or the Leases and all proceeds, products,
substitutions, and exchanges thereof (the Lands, the Leases, and the real and
personal Property interests described in this Section being the "Mortgaged
Property").

                  1.3 Assignment of Security. Mortgagor, for the same
consideration, hereby grants to Mortgagee any and all rights of Mortgagor to
Liens securing payment of proceeds from the sale of production from the
Mortgaged Property.

                  1.4 After-Acquired Property. Mortgagor, for the same
consideration, hereby grants, bargains, sells, conveys, transfers, and assigns
to the Trustee or grants to Mortgagee a continuing security interest in, as the
case may be, all additional right, title, or interest which Mortgagor may
hereafter acquire or become entitled to in the interests, Properties, Lands,
Leases, and premises aforesaid, and in the oil, gas, or other minerals in and
under or produced from or attributable to any of the Lands or Leases, which
additional right, title, and interest, when acquired, shall constitute
"Mortgaged Property," the same as if expressly described and conveyed herein.

                  1.5 Habendum. TO HAVE AND TO HOLD all and singular the
Mortgaged Property and all other Property which, by the terms hereof, has or may
hereafter become subject to the Liens of this Deed of Trust, together with all
rights, hereditaments, and appurtenances in anywise belonging thereto, to the
Trustee or Mortgagee, as the case may be, or the successors or assigns of either
of them forever.

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                                    ARTICLE 2

                              INDEBTEDNESS SECURED

                  This conveyance is made, IN TRUST, HOWEVER, to secure and
enforce the payment of the following indebtedness, obligations, and liabilities:

                  2.1 Specific Obligations. The Obligations, including, without
limitation, the indebtedness evidenced by (a) the Credit Agreement, (b) the
Promissory Note dated December 19, 2002, executed by Borrowers to the order of
the Lenders pursuant to the Credit Agreement in the aggregate face amount of up
to $50,000,000, bearing interest and being payable as provided therein or as
provided in the Credit Agreement, with a final maturity of December 19, 2004,
and (c) Promissory Note dated June 1, 2003, executed by Borrowers to the order
of the Lenders pursuant to the Credit Agreement in the face amount of
$3,599,998, bearing interest and being payable as provided therein or as
provided in the Credit Agreement, with a final maturity of December 19, 2004.

                  2.2 Additional Indebtedness.

                  (a) Payment of and performance of any and all present or
         future obligations of Borrowers under Commodity Hedge Agreements, as
         defined in the Credit Agreement.

                  (b) Payment of and performance of any and all present or
         future obligations of Borrowers under any Rate Management Transaction,
         as defined in the Credit Agreement, entered into by and between
         Borrowers and a Lender.

                  (c) Payment of and performance of any and all present or
         future obligations of Borrowers under any guaranty in favor of Lenders
         of any of the Borrowers' subsidiary's obligations under Commodity Hedge
         Agreements and Rate Management Transactions and all present or future
         obligations of Borrowers or Borrowers' subsidiaries under Commodity
         Hedge Agreements and Rate Management Transactions.

                  2.3 Other and Further Indebtedness. This Deed of Trust is
intended to secure a revolving credit line as set forth in the Credit Agreement.
If intermediate paydowns by Borrowers reduce the outstanding Indebtedness to
zero, it is intended that the Liens created under this Deed of Trust shall
remain in full force and effect as long as any Commitment exists. In addition,
it is contemplated that Borrowers may from time to time borrow additional sums
of money from or otherwise be or become obligated to Lenders. This Deed of Trust
is given to secure any and all indebtedness of Borrowers, present or future,
either direct or indirect, primary or secondary, fixed or contingent, which
Borrowers may now or hereafter owe, or as to which Borrowers may in any manner
become obligated to Lenders for payment, including, without limitation,
indebtedness arising by way of guaranty as to obligations of another to Lenders
and indebtedness originally owed to a party other than Lenders but which becomes
owing to Lenders as the result of Lenders having

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<PAGE>

acquired the right to payment thereof. This Deed of Trust shall likewise secure
not only the above described indebtedness, but any and all renewals for any
period, extensions, and rearrangements of all or any portion thereof; and the
Liens under this Deed of Trust shall be cumulative of all other Liens and
security of any and every other kind or character whatsoever securing the
above-described indebtedness. Notwithstanding the foregoing, it is not the
intention of the parties hereto to extend the Liens of this Deed of Trust so as
to violate, or give rise to an allegation of violation of, any provision of any
statute, regulation, rule, ordinance or order of any applicable jurisdiction, or
any agency or subdivision of any of such jurisdictions. In this connection, this
Deed of Trust shall not, solely as to the relevant indebtedness, serve as
security for any indebtedness when for it to do so would violate any provision
of any statute, regulation, rule, ordinance or order of any applicable
jurisdiction, or any agency or subdivision of any of such jurisdictions.

                  2.4 Indebtedness. The word "Indebtedness" wherever used in
this Deed of Trust shall refer to all present and future debts, obligations, and
liabilities described or referred to in this Article 2, subject, however, to the
limitations provided hereinabove in this Article 2.

                                    ARTICLE 3

                                   WARRANTIES

                  3.1 Warranty of Title. Mortgagor hereby binds itself, its
legal representatives, successors, and assigns, to warrant and forever defend
all and singular the Mortgaged Property to the Trustee and the successors and
assigns of the Trustee forever against every Person whomsoever lawfully claiming
or to claim the same or any part thereof. Notwithstanding that this Deed of
Trust covers all of the right, title, and interest, whether now owned and
existing or hereafter acquired or arising, of Mortgagor in and to the Mortgaged
Property, Mortgagor, for itself, its legal representatives, successors, and
assigns, further covenants, represents, and warrants that Mortgagor has good and
indefeasible title to the Mortgaged Property and that the interests of Mortgagor
in and to the Leases and/or Lands described in Exhibit A are not greater than
the working interest nor less than the net revenue interest, overriding royalty
interest, net profit interest, production payment interest, royalty interest, or
other interest payable out of or measured by production set forth in connection
with each oil and gas well described in Exhibit A. In the event Mortgagor owns
any other or greater interest, such additional interest is nonetheless included
in, covered by, and subject to the liens and security interests created by this
Deed of Trust.

                  3.2 Additional Warranties. In consideration of the
Indebtedness, Mortgagor, for itself, its legal representatives, successors, and
assigns, covenants, represents, and warrants that:

                  (a) Leases in Effect. All of the Leases specifically described
         or referred to in Exhibit A are in full force and effect. All
         covenants, express or implied, in respect of the Leases specifically
         described or referred to in Exhibit A, or of any assignment of any of
         such Leases, which may affect the validity of any of such Leases, have
         been performed insofar as such Leases pertain to the Lands.

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                  (b) Interests Free of Liens. The interests of Mortgagor in the
         Mortgaged Property are free and clear of all Liens except for Permitted
         Liens. All gross production taxes and all taxes as to which non-payment
         could result in a Lien against any of the Mortgaged Property have been
         paid.

                  (c) Representations and Warranties. As of the date hereof, all
         representations and warranties of Mortgagor set forth in the Credit
         Agreement are true and correct in all material respects, except to the
         extent such representations and warranties relate solely to an earlier
         date, and all such representations and warranties are hereby remade by
         Mortgagor to Mortgagee.

                                    ARTICLE 4

                             COVENANTS OF MORTGAGOR

                  In consideration of the Indebtedness, Mortgagor, for itself,
its legal representatives, successors, and assigns, covenants and agrees as
follows:

                  4.1 Maintenance of Leases. Mortgagor will keep and continue
all Leases, estates, and interests herein described and all contracts and
agreements relating thereto in full force and effect in accordance with the
terms thereof and will not permit the same to lapse or otherwise become impaired
for failure to comply with the obligations thereof, whether express or implied.
In this connection, Mortgagor shall not release any of the Leases without the
prior written consent of Mortgagee.

                  4.2 Maintenance of Property. Mortgagor will keep and maintain
all improvements, personal Property, and equipment now or hereafter situated on
the Lands and constituting a portion of the Mortgaged Property and used or
obtained in connection therewith in good repair and condition, ordinary wear and
tear excepted, and will not tear down or remove the same or permit the same to
be torn down or removed without the prior consent of Mortgagee, except in the
usual course of operations as may be required for replacement when otherwise in
compliance with the provisions of this Deed of Trust and the Credit Agreement.

                  4.3 Pooling or Unitization. Mortgagor will not, without the
prior written consent of Mortgagee, pool or unitize all or any part of the
Mortgaged Property where the pooling or unitization would result in the
diminution of the net revenue interest of Mortgagor in production from the
pooled or unitized lands attributable to the Mortgaged Property constituting a
portion of such pooled or unitized lands. Immediately after the formation of any
pool or unit in accordance herewith, Mortgagor will furnish to Mortgagee a
conformed copy of the pooling agreement, declaration of pooling, or other
instrument creating the pool or unit. The interest of Mortgagor included in any
pool or unit attributable to the Mortgaged Property or any part thereof shall
become a part of the Mortgaged Property and shall be subject to the Liens hereof
in the same manner and with the same effect as though the pool or unit and the
interest of Mortgagor therein were specifically described in Exhibit A. In the
event any proceedings of any Governmental Authority which could

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<PAGE>

result in pooling or unitizing all or any part of the Mortgaged Property are
commenced. Mortgagor shall give immediate written notice thereof to Mortgagee.
Any pooling or unitization of all or any part of the Mortgaged Property in
violation of this Section shall be of no force or effect against the Trustee or
Mortgagee.

                  4.4 Operation of Mortgaged Property. Mortgagor will operate
or. to the extent that the right of operation is vested in others, will exercise
its best efforts to require the operator to operate the Mortgaged Property and
all wells now or hereafter located thereon continuously and in a prudent and
workmanlike manner in accordance with the best usage of the field and in
accordance with all applicable Requirements of Law. Mortgagor will comply with
all terms and conditions of the Leases and each assignment or contract
obligating Mortgagor in any way with respect to the Mortgaged Property; but
nothing herein shall be construed to empower Mortgagor to bind the Trustee or
Mortgagee to any contract or obligation or render the Trustee or Mortgagee in
any way responsible or liable for bills or obligations incurred by Mortgagor.

                  4.5 Compliance with Operating Agreements. Mortgagor agrees to
promptly pay all bills for labor and materials incurred in the operation of the
Mortgaged Property and will promptly pay its share of all costs and expenses
incurred under any joint operating agreement affecting the Mortgaged Property or
any portion thereof; will furnish Mortgagee, as and when requested, full
information as to the status of any joint account maintained with others under
any such operating agreement; will not take any action to incur any liability or
Lien thereunder; and will not enter into any new operating agreement or any
amendment of any existing operating agreement affecting the Mortgaged Property
without the prior written consent of Mortgagee. Furthermore. Mortgagor will not
consent or agree to participate in any proposed operation under any presently
existing operating agreement affecting the Mortgaged Property unless Mortgagor
obtains the prior written consent of Mortgagee and, if requested by Mortgagee,
deposits with the operator or Mortgagee, where Mortgagor is a non-operator, or
with Mortgagee, where Mortgagor is an operator, Mortgagor's share of the
estimated cost of the proposed operation prior to electing to participate in the
operation. To the extent that Mortgagor is unable to consent to any proposed
operation with respect to any of the Mortgaged Property, prior to electing not
to participate in the proposed operation, Mortgagor will use its best efforts,
to the extent practicable and to the extent allowed to do so under the relevant
operating agreement or other applicable contract, to farmout to others
acceptable to Mortgagee, on the best terms obtainable and acceptable to
Mortgagee, the interest or relevant portion of the interest of Mortgagor in the
proposed operation.

                  4.6 Access to Mortgaged Property. Mortgagor will permit
Mortgagee and its accredited agents, representatives, attorneys and employees,
at the expense of Mortgagor, at all times to go upon, examine, inspect, conduct
environmental audits and other testing of, and remain on, the Mortgaged
Property, and to go upon the derrick floor of any well at any time drilled or
being drilled thereon, and will furnish Mortgagee, upon request, all pertinent
information regarding the development and operation of the Mortgaged Property.

                  4.7 Waivers. Mortgagor hereby expressly waives, to the full
extent permitted by applicable law, any and all rights or privileges of
marshalling of assets, sale in inverse order of alienation, notices,
appraisements, redemption, and any prerequisite in the event of foreclosure of
the

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<PAGE>

Liens created herein. Mortgagee at all times shall have the right to release any
part of the Mortgaged Property now or hereafter subject to the Liens of this
Deed of Trust, any part of the proceeds of production or other income herein
or hereafter assigned or pledged, or any other security it now has or may
hereafter have securing the Indebtedness, without releasing any other part of
the Mortgaged Property, proceeds, or income, and without affecting the Liens
hereof as to the part or parts of the Mortgaged Property, proceeds, or income
not so released or the right to receive future proceeds and income.

                  4.8 Compliance with Laws. Mortgagor will comply with all
Requirements of Law applicable to the Mortgaged Property and the operations
conducted thereon, including, without limitation, the Natural Gas Policy Act of
1978, as amended, and Environmental Laws; and cause all employees, crew members,
agents, contractors, sub-contractors, and future lessees (pursuant to
appropriate lease provisions) of Mortgagor, while such Persons are acting within
the scope of their relationship with Mortgagor, to comply with all such
Requirements of Law as may be necessary or appropriate to enable Mortgagor to so
comply.

                  4.9 Hazardous Substances Indemnification. MORTGAGOR HEREBY
INDEMNIFIES AND HOLDS MORTGAGEE AND THE LENDERS AND THEIR RESPECTIVE
SHAREHOLDERS, OFFICERS, DIRECTORS, EMPLOYEES, AGENTS, ATTORNEYS-IN-FACT, AND
AFFILIATES AND THE TRUSTEE HARMLESS FROM AND AGAINST ANY AND ALL CLAIMS, LOSSES,
DAMAGES, LIABILITIES, FINES, PENALTIES, CHARGES, ADMINISTRATIVE AND JUDICIAL
PROCEEDINGS AND ORDERS, JUDGMENTS, REMEDIAL ACTIONS, REQUIREMENTS AND
ENFORCEMENT ACTIONS OF ANY KIND, AND ALL COSTS AND EXPENSES INCURRED IN
CONNECTION THEREWITH (INCLUDING, WITHOUT LIMITATION, ATTORNEYS' FEES AND
EXPENSES), ARISING DIRECTLY OR INDIRECTLY, IN WHOLE OR IN PART, FROM (a) THE
PRESENCE OF ANY HAZARDOUS SUBSTANCES ON, UNDER, OR FROM ANY MORTGAGED PROPERTY,
WHETHER PRIOR TO OR DURING THE TERM HEREOF, (b) ANY ACTIVITY CARRIED ON OR
UNDERTAKEN ON OR OFF ANY MORTGAGED PROPERTY, WHETHER PRIOR TO OR DURING THE TERM
HEREOF, AND WHETHER BY MORTGAGOR OR ANY PREDECESSOR IN TITLE, EMPLOYEE, AGENT,
CONTRACTOR, OR SUBCONTRACTOR OF MORTGAGOR OR ANY OTHER PERSON AT ANY TIME
OCCUPYING OR PRESENT ON ANY MORTGAGED PROPERTY, IN CONNECTION WITH THE HANDLING,
TREATMENT, REMOVAL, STORAGE, DECONTAMINATION, CLEANUP, TRANSPORTATION, OR
DISPOSAL OF ANY HAZARDOUS SUBSTANCES AT ANY TIME LOCATED OR PRESENT ON OR UNDER
SUCH PROPERTY, (c) ANY RESIDUAL CONTAMINATION ON OR UNDER ANY MORTGAGED
PROPERTY, (d) ANY CONTAMINATION OF ANY MORTGAGED PROPERTY OR NATURAL RESOURCES
ARISING IN CONNECTION WITH THE GENERATION, USE, HANDLING, STORAGE,
TRANSPORTATION, OR DISPOSAL OF ANY HAZARDOUS SUBSTANCE BY MORTGAGOR OR ANY
EMPLOYEE, AGENT, CONTRACTOR, OR SUBCONTRACTOR OF MORTGAGOR WHILE SUCH PERSONS
ARE ACTING WITHIN THE SCOPE OF THEIR RELATIONSHIP WITH MORTGAGOR, IRRESPECTIVE
OF WHETHER ANY OF SUCH ACTIVITIES WERE OR WILL BE UNDERTAKEN IN ACCORDANCE WITH
APPLICABLE REQUIREMENTS OF LAW, OR (e) THE PERFORMANCE AND ENFORCEMENT OF THIS
DEED OF TRUST OR ANY OTHER ACT OR OMISSION IN CONNECTION WITH OR RELATED TO THIS
DEED OF TRUST OR THE TRANSACTIONS CONTEMPLATED HEREBY, INCLUDING, WITHOUT
LIMITATION, ANY OF THE FOREGOING IN THIS SECTION ARISING FROM NEGLIGENCE,
WHETHER SOLE OR CONCURRENT, ON THE PART OF MORTGAGEE OR ANY LENDER OR ANY OF
THEIR RESPECTIVE SHAREHOLDERS, OFFICERS, DIRECTORS, EMPLOYEES, AGENTS,
ATTORNEYS-IN-FACT, OR AFFILIATES OR THE TRUSTEE; WITH THE FOREGOING INDEMNITY
SURVIVING SATISFACTION OF THE INDEBTEDNESS, THE TERMINATION OF THE CREDIT
AGREEMENT, AND THE RELEASE OF THE LIENS CREATED HEREBY.

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                  4.10 Site Assessments. Mortgagee (by its officers, employees
and agents) at any time and from time to time, either prior to or after the
occurrence of an Event of Default, may contract, at the expense of Mortgagor,
for the services of Persons (the "Site Reviewers") to perform environmental site
assessments and other tests ("Site Assessments") on all or any portion of the
Mortgaged Property for the purpose of determining whether any environmental
condition exists on any Mortgaged Property which could reasonably be expected to
result in any liability, cost, or expense to Mortgagee or any owner, occupier,
or operator of such Mortgaged Property. The Site Assessments may be performed at
any time or times, upon reasonable notice, and under reasonable conditions
established by Mortgagor which do not impede the performance of the Site
Assessments. The Site Reviewers are hereby authorized to enter upon all or any
portion of the Mortgaged Property for such purposes. The Site Reviewers are
further authorized to perform both above and below the ground testing for
environmental damage or the presence of Hazardous Substances on the Mortgaged
Property and such other tests on the Mortgaged Property as may be necessary to
conduct the Site Assessments in the reasonable opinion of the Site Reviewers.
Mortgagor will supply to the Site Reviewers such historical and operational
information regarding the Mortgaged Property as may be reasonably requested by
the Site Reviewers to facilitate the Site Assessments and will make available
for meetings with the Site Reviewers appropriate personnel having knowledge of
such matters. On request, Mortgagee shall make the results of such Site
Assessments available to Mortgagor, which, prior to an Event of Default, may at
its election participate under reasonable procedures in the direction of such
Site Assessments and the description of tasks of the Site Reviewers. The cost of
performing all Site Assessments shall be paid by Mortgagor upon demand of
Mortgagee and any such obligations shall be Indebtedness secured by this Deed of
Trust.

                  4.11 Uneconomic Wells. Should proceeds from the sale of
production from any oil and/or gas well constituting part of the Mortgaged
Property (net of production, severance and windfall profit taxes and royalties,
overriding royalties and other payments out of or measured by production) not
exceed the expense of operation of such well (including, but not limited to,
operator's overhead, payments to contractors and suppliers, and annual taxes
assessed on the basis of the value of the Property prorated on a monthly basis,
but expressly excluding any portion of the cost of drilling or completing the
relevant well or the cost of non-routine workover or remedial operations) for a
period in excess of three consecutive calendar months, then, upon receipt by
Mortgagor of written notification from Mortgagee, Mortgagor will (a) take all
necessary steps to abandon the relevant well, or (b) provide from sources other
than proceeds from the sale of production attributable to the Mortgaged Property
(i.e., through borrowings or contractual commitments obtained from third parties
not in violation of any provision of this Deed of Trust or any other Loan
Document) the funds required to pay the share of Mortgagor of the expenses
associated with the continuing operation of such well.

                  4.12 Performance of Gas Contracts. Mortgagor will perform and
observe in all material respects all of its obligations under each contract
relating to the sale of gas produced from or attributable to the Mortgaged
Property and will not, except in good faith and as the result of arm's length
negotiations and with prior written notice to Mortgagee, change, modify, amend
or waive any of the terms or provisions of any such contract or take any other
action which would release any other party from its obligations or liabilities
under any such contract.

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                  4.13 Covenants Running with the Land. All covenants and
agreements herein contained shall constitute covenants running with the Land.

                                    ARTICLE 5

                   DEFEASANCE, FORECLOSURE AND OTHER REMEDIES

                  5.1 Defeasance. Should the Indebtedness be paid, then the
conveyance of the Mortgaged Property shall become of no further force and
effect, and, at the request and expense of Mortgagor, the Lien granted hereunder
shall be released, without recourse or warranty; otherwise, it shall remain in
full force and effect.

                  5.2 Events of Default. The occurrence of any Event of Default
under the Credit Agreement shall constitute an Event of Default under this Deed
of Trust.

                  5.3 Acceleration and Exercise of Power of Sale.

                  (a) Upon the occurrence of an Event of Default specified in
         Sections 7.1(f) or 7.1(g) of the Credit Agreement, the aggregate
         principal amount of all Indebtedness then outstanding and all interest
         accrued thereon shall automatically become immediately due and payable,
         without presentment, demand, protest, notice of protest, default or
         dishonor, notice of intent to accelerate maturity, notice of
         acceleration of maturity, or other notice of any kind, all of which are
         hereby expressly waived by Mortgagor to the full extent permitted by
         applicable law. Upon the occurrence of any other Event of Default,
         Mortgagee may declare the aggregate principal amount of all
         Indebtedness then outstanding and all interest accrued thereon
         immediately due and payable, whereupon the same shall become
         immediately due and payable without presentment, demand, protest,
         notice of protest, default or dishonor, notice of intent to accelerate
         maturity, notice of acceleration of maturity, or other notice of any
         kind, all of which are hereby expressly waived by Mortgagor to the full
         extent permitted by applicable law.

                  (b) Upon the occurrence of any Event of Default or at any time
         thereafter while the Indebtedness or any part thereof remains unpaid,
         it shall be the duty of the Trustee, on request of Mortgagee (which
         request is hereby presumed), to enforce this Trust and, after
         advertising the time and place of the sale for at least 21 days prior
         to the day of sale, by posting or causing to be posted a written or
         printed notice thereof at the courthouse door and by filing a copy of
         such notice in the office of the county clerk of each county in which
         the Mortgaged Property or any part thereof may be situated, and serving
         written notice of the proposed sale on each debtor obligated to pay the
         Indebtedness according to the records of Mortgagee, by postage prepaid,
         certified United States mail, at the most recent address for such
         debtor as shown by the records of Mortgagee, at least 21 days prior to
         the day of sale, to sell the

                                       10
<PAGE>

         Mortgaged Property, either as a whole or in parcels, as the Trustee may
         deem proper, at public venue at the courthouse of the county in which
         the Mortgaged Property or any part thereof may be situated (and being
         the county designated in the notice of sale) on the first Tuesday of
         any month between the hours of 10:00 a.m. and 4:00 p.m., to the highest
         bidder for cash, and after such sale to execute and deliver to the
         purchaser or purchasers good and sufficient deeds and assignments,
         conveying such Property so sold to the purchaser or purchasers with
         general warranty of title made on behalf of Mortgagor. The Trustee, or
         his successor or substitute, is hereby authorized and empowered to
         appoint any one or more Persons as his attorneys-in-fact or agents to
         act as Trustee under him and in his name, place and stead, such
         appointment to be evidenced by a written instrument executed by the
         Trustee, or his successor or substitute, to perform any one or more act
         or acts necessary or incident to any sale under the power of sale
         hereunder, including, without limitation, the posting and filing of any
         notices, the conduct of the sale and the execution and delivery of any
         instruments conveying the Mortgaged Property as a result of the sale.
         but in the name and on behalf of the Trustee, or his successor or
         substitute; and all acts done or performed by such attorneys-in-fact or
         agents shall be valid, lawful and binding as if done or performed by
         the Trustee, or his successor or substitute. No single sale or series
         of sales by the Trustee shall extinguish the Lien or exhaust the power
         of sale hereunder except with respect to the items of Property sold,
         but such Lien and power shall exist for so long as and may be exercised
         in any manner by law or as herein provided as often as the
         circumstances require to give Mortgagee full relief hereunder. The
         purchaser at any such sale shall not assume, nor shall the heirs, legal
         representatives, successors or assigns of such purchaser, be deemed to
         have assumed, by reason of the acquisition of Property or rights
         mortgaged hereunder, any liability or obligation of any lessee or
         operator of the Mortgaged Property, or any part thereof, arising by
         reason of any occurrence taking place prior to such sale. It shall not
         be necessary to have present, or to exhibit at any such sale, any of
         the personal Property subject to the Lien hereof.

                  5.4 Rights as Secured Party. Upon the occurrence of any Event
of Default, Mortgagee shall be entitled to all of the rights, powers, and
remedies afforded a secured party by the UCC with respect to the personal
Property and fixtures and as-extracted collateral in which Mortgagee has been
granted a security interest hereby, or Mortgagee may proceed in accordance with
the provisions hereof as to both the real and personal Property covered hereby.

                  5.5 Application of Proceeds of Sale. The Trustee is authorized
to receive the proceeds of each sale of Mortgaged Property and apply the same as
follows:

                  FIRST: to the payment of all necessary costs and expenses
                  incident to the execution of this Deed of Trust, including,
                  but not limited to, a fee to the Trustee of 5% of the amount
                  realized at the sale, if required by the Trustee;

                                       11
<PAGE>

                  SECOND: to any and all Indebtedness then hereby secured,
                  application to be made in such order and in such manner as
                  Mortgagee may, in its discretion, elect;

                  THIRD: the balance, if any, to Mortgagor or its successors or
                  assigns, or other Person legally entitled thereto.

                  5.6 Substitute Trustee. In the event of the death of the
Trustee, or his removal from the State of Texas, or his failure, refusal, or
inability for any reason to make any such sale or to perform any of the trusts
herein declared, or at any time, whether with or without cause, Mortgagee may
appoint, in writing, a substitute trustee who shall thereupon succeed to all the
estates, rights, powers, and trusts herein granted to and vested in the Trustee.
In the same events as first above stated, and in the same manner, successive
substitute Trustees may thereafter be appointed.

                  5.7 Statements by Trustee. It is agreed that in any deed or
deeds given by any Trustee any and all statements of fact or other recitals
therein made as to the identity of the holder or holders of the Indebtedness, or
as to default in the payments thereof or any part thereof, or as to the breach
of any covenants herein contained, or as to the request to sell, notice of sale,
time, place, terms and manner of sale, and receipt, application, and
distribution of the money realized therefrom, or as to the due and proper
appointment of a substitute trustee, and, without being limited by the
foregoing, as to any other or additional act or thing having been done by
Mortgagee or the Trustee, shall be taken by all courts of law and equity as
prima facie evidence that the statements or recitals state facts and are without
further question to be so accepted. Mortgagor does hereby ratify and confirm any
and all acts that the Trustee may lawfully do in the premises by virtue of the
terms and conditions of this Deed of Trust.

                  5.8 Suit to Collect and Foreclose. Mortgagee, at its election,
or the Trustee, upon written request of Mortgagee, may proceed by suit or suits,
at law or in equity, to enforce the payment of the Indebtedness in accordance
with the terms hereof and of the notes, guaranties, or other documents
evidencing it, and to foreclose the Lien of this Deed of Trust as against all or
any portion of the Mortgaged Property and to have such Property sold under the
judgment or decree of a court of competent jurisdiction.

                  5.9 Mortgagee or Trustee as Purchaser. Mortgagee or the
Trustee may be a purchaser of all or any portion of the Mortgaged Property at
any sale thereof, whether such sale be under the power of sale hereinabove
vested in the Trustee, upon any other foreclosure of the Lien hereof, or
otherwise. Mortgagee or the Trustee so purchasing shall, upon any such purchase,
acquire title to the Mortgaged Property so purchased, free of the Lien of this
Deed of Trust and free of all rights of redemption in Mortgagor.

                  5.10 Entry and Operation. Upon the occurrence of any Event of
Default, then in each and every such case and in addition to the other rights
and remedies hereunder, the Trustee or Mortgagee, whether or not the
Indebtedness shall have become due and payable, may, but shall not be obligated
to, enter into and upon and take possession of all or any portion of the
Mortgaged Property and may exclude Mortgagor, its agents and servants wholly
therefrom and have, hold, use,

                                       12
<PAGE>

operate, manage, and control all or any portion of the Mortgaged Property and
produce the oil, gas, and other minerals therefrom and market the same, all at
the sole risk and expense of Mortgagor and at the expense of the Mortgaged
Property, applying the net proceeds so derived, first, to the cost of
maintenance and operation of such Mortgaged Property; second, to the payment of
the Indebtedness, application to be made first to interest and then to
principal; and the balance thereof, if any, shall be paid to Mortgagor. Upon
such payment of all such costs and Indebtedness, the Mortgaged Property shall be
returned to Mortgagor in its then condition, and neither the Trustee nor
Mortgagee shall be liable to Mortgagor for any damage or injury to the Mortgaged
Property except such as may be caused through the fraud or willful misconduct of
the Trustee or Mortgagee, as the case may be.

                  5.11 Power of Attorney to Mortgagee. Mortgagor does hereby
designate Mortgagee as the agent of Mortgagor to act in the name, place, and
stead of Mortgagor in the exercise of each and every remedy set forth herein and
in conducting any and all operations and taking any and all action reasonably
necessary to do so, recognizing such agency in favor of Mortgagee to be coupled
with the interests of Mortgagee under this Deed of Trust and, thus, irrevocable
so long as this Deed of Trust is in force and effect.

                  5.12 Remedies Cumulative and Non-Exclusive. The rights of
entry, sale, or suit, as hereinabove or hereinafter conferred, are cumulative of
all other rights and remedies herein or by law or in equity provided, and shall
not be deemed to deprive Mortgagee or the Trustee of any such other legal or
equitable rights or remedies, by judicial proceedings or otherwise, appropriate
to enforce the conditions, covenants, and terms of this Deed of Trust and the
other Loan Documents. The employment of any remedy hereunder or otherwise shall
not prevent the concurrent or subsequent employment of any other appropriate
remedy or remedies.

                                    ARTICLE 6

                            ASSIGNMENT OF PRODUCTION

                  6.1 Assignment. In addition to the conveyance to the Trustee
herein made, Mortgagor does hereby transfer, assign, deliver and convey unto
Mortgagee, its successors and assigns, all of the oil, gas, and other minerals
produced, saved, or sold from the Mortgaged Property and attributable to the
interests of Mortgagor therein subsequent to 7:00 a.m. on the first day of the
month in which this Deed of Trust is executed, together with the proceeds of any
sale thereof. Mortgagor hereby directs any purchaser now or hereafter taking any
production from the Mortgaged Property to pay to Mortgagee such proceeds derived
from the sale thereof and to continue to make payments directly to Mortgagee
until notified in writing by Mortgagee to discontinue the same. The purchaser of
any such production shall not be required to see to the application of the
proceeds thereof by Mortgagee, and payment made to Mortgagee shall be binding
and conclusive as between such purchaser and Mortgagor. Mortgagor further agrees
to perform all such acts and to execute all such further assignments, transfer
and division orders, and other instruments as may be required or desired by
Mortgagee or any other party to have such proceeds and revenues so paid to
Mortgagee.

                                       13
<PAGE>

                  6.2 Postponement of Payment. For its convenience, Mortgagee
has elected not to exercise immediately its right to receive payment to it
directly of the proceeds of any sale of the oil, gas and other minerals produced
or sold from the Mortgaged Property and the purchasers may continue to make such
payment or delivery of the proceeds to Mortgagor until such time as Mortgagor
and the purchasers have received notice that an Event of Default has occurred
and is continuing, and that the purchasers are directed to make payment or
delivery of the proceeds directly to Mortgagee. Such failure by Mortgagee to
exercise its rights immediately shall not in any way waive the right of
Mortgagee to receive any of the proceeds, or to make any such demand, or to
affect any such assignment as to any proceeds not theretofore paid or delivered
to Mortgagor. In this regard, if any of the proceeds are paid or delivered
directly to Mortgagee and then, at the request of Mortgagee, the proceeds are.
for a period or periods of time, paid or delivered to Mortgagor, Mortgagee shall
nevertheless have the right, effective upon written notice, to require that
future proceeds be again paid or delivered directly to it. Mortgagee shall never
be required to send any such notice to all purchasers, and may direct such
notice only to those purchasers as it may, in its discretion, desire. It shall
never be necessary for Mortgagee to institute legal proceedings to enforce the
assignment of hydrocarbons, proceeds, or other rents, profits, or income
contained in this instrument. It shall not be necessary for Mortgagee to obtain
possession of the Mortgaged Property as a prerequisite to Mortgagee's right to
collect or receive any hydrocarbons, other minerals, proceeds, or other rents,
profits, or income assigned to Mortgagee under this instrument. Mortgagor and
Mortgagee expressly agree and it is the express intention of Mortgagor and
Mortgagee that in no event will any reduction in the obligations be measured by
the fair market value of the hydrocarbons, other minerals, proceeds, or other
rents, profits, or income assigned to Mortgagee under this instrument.

                  6.3 Change of Purchaser. Should any purchaser taking the
production from the Mortgaged Property fail to make prompt payment to Mortgagee
in accordance with the provisions of Section 6.1, Mortgagee shall have the
right, at the expense of Mortgagor, to demand a change of connection and to
designate another purchaser with whom a new connection may be made, without any
liability on the part of Mortgagee in making such selection, so long as ordinary
care is used in the making thereof. Promptly upon such demand, Mortgagor shall
take all necessary and appropriate action to effect such change of connection.

                  6.4 Application of Proceeds. Mortgagor authorizes and empowers
Mortgagee to receive, hold, and collect all sums of money paid to Mortgagee in
accordance with the provisions of Section 6.1, and to apply the same as
hereinafter provided, all without any liability or responsibility on the part of
Mortgagee, save and except as to good faith in so receiving and applying such
sums. Mortgagee may apply all sums received by Mortgagee pursuant to Section 6.1
to the payment of the Indebtedness, application to be made in such manner as
Mortgagee may elect, regardless of whether the application so made shall exceed
the payments of principal and interest then due as provided in the Loan
Documents. After such application has been so made by Mortgagee, the balance of
any such sums shall be paid to Mortgagor.

                  6.5 No Postponement of Installments on Indebtedness. It is
understood and agreed that should such payments provided for by Section 6.1 be
less than the sum or sums then due on the Indebtedness, such sum or sums then
due shall nevertheless be paid by Mortgagor in

                                       14
<PAGE>

accordance with the provisions of the Loan Documents, and neither the assignment
made pursuant to Section 6.1 nor any other provisions hereof shall in any manner
be construed to affect the terms and provisions of the Loan Documents. Likewise,
neither the assignment made pursuant to Section 6.1 nor any other provisions
hereof shall in any manner be construed to affect the Liens, rights, title, and
remedies herein granted securing the Indebtedness or the liability of Mortgagor
therefor. The rights under this Article VI are cumulative of all other rights,
remedies, and powers granted under this Deed of Trust and are cumulative of any
other security which Mortgagee now holds or may hereafter hold to secure the
payment of the Indebtedness.

                  6.6 Turnover to Mortgagee. Should Mortgagor receive any of the
proceeds of any sale of oil, gas, or other minerals produced, saved, or sold
from the Mortgaged Property, which under the terms hereof should have been
remitted to Mortgagee, Mortgagor will immediately remit same in full to
Mortgagee.

                  6.7 Release of Proceeds Upon Payment of Indebtedness. Upon
payment in full of all Indebtedness and the termination of the Commitment, the
remainder of such proceeds held by Mortgagee, if any, shall be paid over to
Mortgagor upon demand, and a release of the interest hereby assigned will be
made, without recourse or warranty, by Mortgagee to Mortgagor at its request and
its expense.

                  6.8 Duty of Mortgagee. Mortgagee shall not be liable for any
failure to collect, or for any failure to exercise diligence in collecting, any
funds assigned hereunder. Mortgagee shall be accountable only for funds actually
received.

                  6.9 Power of Attorney to Mortgagee. Mortgagor does hereby
designate Mortgagee as the agent of Mortgagor to act in the name, place, and
stead of Mortgagor for the purpose of taking any and all actions deemed by
Mortgagee necessary for the realization by Mortgagee of the benefits of the
assignment of production provided herein, recognizing such agency in favor of
Mortgagee to be coupled with the interests of Mortgagee under this Deed of Trust
and, thus, irrevocable so long as this Deed of Trust is in force and effect.

                                    ARTICLE 7

                                 MISCELLANEOUS

                  7.1 Further Assurances. Upon request of Mortgagee, Mortgagor
will promptly correct any defects, errors, or omissions in the execution or
acknowledgment of this Deed of Trust or any other Loan Document, and execute,
acknowledge, and deliver such other assurances and instruments as shall, in the
opinion of Mortgagee, be necessary to fulfill the terms of this Deed of Trust.

                  7.2 Interest. Any provision in any document that may be
executed in connection herewith to the contrary notwithstanding, Mortgagee shall
in no event be entitled to receive or

                                       15
<PAGE>

collect, nor shall any amounts received hereunder be credited so that Mortgagee
shall be paid, as interest a sum greater than that authorized by law. If any
possible construction of this Deed of Trust or any Loan Document seems to
indicate any possibility of a different power given to Mortgagee or any
authority to ask for, demand, or receive any larger rate of interest, this
clause shall override and control, and proper adjustments shall be made
accordingly.

                  7.3 Agreement as Entirety. This Deed of Trust, for convenience
only, has been divided into Articles, Sections, and subsections. The rights,
powers, privileges, duties, and other legal relations of Mortgagor, the Trustee,
and Mortgagee shall be determined from this Deed of Trust as an entirety and
without regard to the aforesaid division into Articles, Sections, and
subsections and without regard to headings affixed to such Articles, Sections,
or subsections.

                  7.4 Number and Gender. Whenever the context requires,
reference herein made to the single number shall be understood to include the
plural, and the plural shall likewise be understood to include the singular.
Words denoting sex shall be construed to include the masculine, feminine, and
neuter when such construction is appropriate; and specific enumeration shall not
exclude the general, but shall be construed as cumulative.

                  7.5 Rights and Remedies Cumulative. All rights, powers,
immunities, remedies, and Liens of Mortgagee existing and to exist hereunder or
under any other instruments or at law or in equity and all other or additional
security shall be cumulative and not exclusive, each of the other. Mortgagee
shall, in addition to the rights and remedies herein expressly provided, be
entitled to such other remedies as may now or hereafter exist at law or in
equity for securing and collecting the Indebtedness, for enforcing the covenants
herein, and for foreclosing the Liens hereof. Resort by Mortgagee to any right
or remedy provided for hereunder or at law or in equity shall not prevent
concurrent or subsequent resort to the same or any other right or remedy. No
security heretofore, herewith, or subsequently taken by Mortgagee shall in any
manner impair or affect the security given by this Deed of Trust or any security
by endorsement or otherwise presently or previously given; and all security
shall be taken, considered, and held as cumulative.

                  7.6 Parties in Interest. This Deed of Trust shall be binding
upon the parties and their respective heirs, administrators, legal
representatives, successors, and assigns and shall inure to the benefit of the
Mortgagee and its legal representatives, successors, and assigns. The terms used
to designate any of the parties herein shall be deemed to include the heirs,
administrators, legal representatives, successors, and assigns of such parties.
The term "Mortgagee" shall also include any lawful owner, holder, or pledgee of
any Indebtedness.

                  7.7 Supplements. Without in any manner limiting the effect of
Section 1.4 or any other provisions of this Deed of Trust as to the binding
effect of this Deed of Trust on after-acquired rights of Mortgagor, it is
contemplated by the parties hereto that from time to time additional interests
and properties may or will be added to the interests and properties subject to
the Liens, rights, titles, and interests created by this Deed of Trust by means
of supplemental indentures identifying this Deed of Trust and describing such
interests and properties to be so added and included. Upon the execution of any
such supplemental indenture, the Liens, rights, titles, and interests created
herein shall immediately attach to and be effective with respect to any such
interests

                                       16
<PAGE>

and properties so described, the same as if such interests and properties had
been specifically described herein, and such interests and properties being
included in the term "Mortgaged Property," as used herein.

                  7.8 Invalidity. In the event that any one or more of the
provisions contained in this Deed of Trust shall for any reason be held invalid,
illegal, or unenforceable in any respect, such invalidity, illegality, or
unenforceability shall not affect any other provision of this Deed of Trust or
any other Loan Document.

                  7.9 Construction. All titles or headings to Articles,
Sections, subsections, or other divisions of this Deed of Trust or the exhibits
hereto are only for the convenience of the parties and shall not be construed to
have any effect or meaning with respect to the other content of such Articles,
Sections, subsections, or other divisions, such other content being controlling
as to the agreement among the parties hereto. Article, Section, subsection, and
Exhibit references herein are to such Articles, Sections, subsections, and
Exhibits of this Deed of Trust unless otherwise specified. The words "hereby,"
"herein," "hereinabove," "hereinafter," "hereinbelow," "hereof," and "hereunder"
when used in this Deed of Trust shall refer to this Deed of Trust as a whole and
not to any particular Article, Section, subsection, or provision of this Deed of
Trust.

                  7.10 Fixtures, Minerals and Accounts. Without in any manner
limiting the generality of any of the foregoing hereof, some portions of the
personal Property described hereinabove are or are to become fixtures on the
Lands. In addition, the security interest created hereby under applicable
provisions of the UCC attaches to minerals, including oil and gas, and accounts
resulting from the sale thereof, at the wellhead or minehead located on the
Lands.

                  7.11 Financing Statement Filings. This Deed of Trust may be
filed as provided in Article 9 of the UCC to assure that the security interests
granted by this Deed of Trust are perfected. In this connection, this Deed of
Trust may be presented to a filing officer under the UCC to be filed in the real
estate records as a Financing Statement covering minerals and fixtures. Further,
Mortgagor authorizes Mortgagee to execute and file at any time and from time to
time any and all Financing Statements and amendments thereto in any UCC
jurisdiction, pursuant to Article 9 of the UCC, as Mortgagee deems necessary in
its sole discretion, in conjunction with this Deed of Trust, and Mortgagor
expressly authorizes execution and filing of such Financing Statements by
Mortgagee without need of signature or execution by Mortgagor.

                  7.12 Addresses. For purposes of filing this Deed of Trust as a
financing statement, the addresses for Mortgagor, as the debtor, and Mortgagee,
as the secured party, are as set forth hereinabove.

                  7.13 Counterparts. For the convenience of the parties, this
Deed of Trust may be executed in multiple counterparts, each of which for all
purposes shall be deemed, and may be enforced from time to time as, a chattel
mortgage, real estate mortgage, deed of trust, security agreement, assignment or
contract, or as one or more thereof. For recording purposes, various
counterparts have been executed, and there may be attached to each such
counterpart an Exhibit A containing only the description of the Mortgaged
Property, or portions thereof, which relates to the

                                       17
<PAGE>

county or state in which the particular counterpart is to be recorded. A
complete, original counterpart of this Deed of Trust with a complete Exhibit A
may be obtained from Mortgagee. Each of the counterparts hereof so executed
shall for all purposes be deemed to be an original, and all such counterparts
shall together constitute but one and the same instrument.

                  7.14 No Waiver by Mortgagee. No course of dealing on the part
of Mortgagee, its officers or employees, nor any failure or delay by Mortgagee
with respect to exercising any of its rights or remedies hereunder shall operate
as a waiver thereof nor shall the exercise or partial exercise of any such right
or remedy shall preclude the exercise of any other right or remedy.

                  7.15 Governing Agreement. This Deed of Trust is made pursuant
and subject to the terms and provisions of the Credit Agreement. In the event of
a conflict between the terms and provisions of this Deed of Trust and those of
the Credit Agreement, the terms and provisions of the Credit Agreement shall
govern and control. The inclusion in this Deed of Trust of provisions not
addressed in the Credit Agreement shall not be deemed a conflict, and all such
additional provisions contained herein shall be given full force and effect.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK]

                                       18
<PAGE>

                  IN WITNESS WHEREOF, this Deed of Trust is executed on the date
of the acknowledgment below but effective as of the 22nd day of September, 2003.

                                       MORTGAGOR AND BORROWERS (DEBTOR):

                                       F-W OIL EXPLORATION L.L.C.

                                       By:______________________________________
                                                  Jim R. Brock
                                                  President and CFO

                                       PRIMEENERGY CORPORATION
                                       PRIMEENERGY MANAGEMENT CORPORATION
                                       PRIME OPERATING COMPANY
                                       EOWS MIDLAND COMPANY
                                       EASTERN OIL WELL SERVICE COMPANY
                                       SOUTHWEST OIL FIELD CONSTRUCTION COMPANY,
                                       each company represented by

                                       _________________________________________
                                       Beverly A. Cummings
                                       Executive Vice President, Treasurer,
                                       and Chief Financial Officer of each of
                                       the companies listed above

                                       19
<PAGE>

STATE OF CONNECTICUT                 Section
                                     Section
COUNTY OF___________________         Section

         BEFORE ME, the undersigned authority, on this day personally appeared
BEVERLY A. CUMMINGS, Executive Vice President, Treasurer, and Chief Financial
Officer of each of PRIMEENERGY CORPORATION, a Delaware corporation, PRIMEENERGY
MANAGEMENT CORPORATION, a New York corporation, PRIME OPERATING COMPANY, a Texas
corporation, EASTERN OIL WELL SERVICE COMPANY, a West Virginia corporation, EOWS
MIDLAND COMPANY, a Texas corporation, and SOUTHWEST OILFIELD CONSTRUCTION
COMPANY, an Oklahoma corporation, on behalf of each of said corporations, known
to me to be the person whose name is subscribed to the foregoing instrument, and
acknowledged to me that she executed the same for the purposes and consideration
therein expressed, as the act and deed of each of such corporations, and in the
capacity therein stated for each of said corporations.

         GIVEN UNDER MY HAND AND SEAL OF OFFICE this _____________ day of
September, 2003.

                                       _________________________________________
                                       NOTARY PUBLIC in and for_________________

THE STATE OF TEXAS                          Section
                                            Section
COUNTY OF HARRIS                            Section

         BEFORE ME, the undersigned authority, on this day personally appeared
JIM R. BROCK, President and CFO of F-W OIL EXPLORATION L.L.C., a Delaware
limited liability company, known to me to be the person whose name is subscribed
to the foregoing instrument, and acknowledged to me that he executed the same
for the purposes and consideration therein expressed, as the act and deed of
such savings bank, and in the capacity therein stated.

         GIVEN UNDER MY HAND AND SEAL OF OFFICE this ____________ day of
September, 2003.

                                  ______________________________________________
                                  NOTARY PUBLIC in and for the State of Texas

                                       20
<PAGE>

                                    EXHIBIT A
                                       TO
                  MORTGAGE, DEED OF TRUST, SECURITY AGREEMENT,
                FINANCING STATEMENT AND ASSIGNMENT OF PRODUCTION

         The designation "Working Interest" or "WI" when used in this Exhibit
means an interest owned in an oil, gas, and mineral lease that determines the
cost-bearing percentage of the owner of such interest. The designation "Net
Revenue Interest" or "NRI" means that portion of the production attributable to
the owner of a working interest after deduction for all royalty burdens,
overriding royalty burdens or other burdens on production, except severance,
production, and other similar taxes. The designation "Overriding Royalty
Interest" or "ORRI" means an interest in production which is free of any
obligation for the expense of exploration, development, and production, bearing
only its pro rata share of severance, production, and other similar taxes and,
in instances where the document creating the overriding royalty interest so
provides, costs associated with compression, dehydration, other treating or
processing, or transportation of production of oil, gas, or other minerals
relating to the marketing of such production. The designation "Royalty Interest"
or "RI" means an interest in production which results from an ownership in the
mineral fee estate or royalty estate in the relevant land and which is free of
any obligation for the expense of exploration, development, and production,
bearing only its pro rata share of severance, production, and other similar
taxes and, in instances where the document creating the royalty interest so
provides, costs associated with compression, dehydration, other treating or
processing or transportation of production of oil, gas, or other minerals
relating to the marketing of such production.

         Any reference in this Exhibit to wells or units is for warranty of
interest administrative convenience, and identification and shall not limit or
restrict the right, title, interest, or properties covered by this Deed of
Trust. All right, title, and interest of Mortgagor in the properties described
herein are and shall be subject to this Deed of Trust, regardless of the
presence of any units or wells not described herein.

         The references to book or volume and page herein refer to the recording
location of each respective Mortgaged Property described herein in the county
where the land covered by the Mortgaged

                                      A-i

<PAGE>

                                    EXHIBIT A
                                       TO
                  MORTGAGE, DEED OF TRUST, SECURITY AGREEMENT,
                FINANCING STATEMENT AND ASSIGNMENT OF PRODUCTION

                         OIL, GAS AND MINERAL INTERESTS

                                      A-ii