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                                                                 EXHIBIT 10.1



              EXPENSE ALLOCATION AND PARTICIPATION AGREEMENT II



                                R E C I T A L S:


         A.      Brigham Oil & Gas, L.P., a Delaware limited partnership
("BOG"), is active in the exploration and development of oil and gas properties
in the domestic United States.

         B.      Gasco Limited Partnership a West Virginia limited partnership
("Gasco"), entered into that certain Expense Allocation and Participation
Agreement dated effective as of April 1, 1996 (the "Previous Agreement")
providing for its participation with BOG in the drilling of certain wells on
properties owned or acquired, in whole or in part, by BOG, up and until March
31, 1997 upon and subject to the provisions contained in the Previous
Agreement.

         B.      Gasco now desires to enter into this Expense Allocation and
Participation Agreement II (the "Agreement") to again participate with BOG in
the drilling of wells on properties owned or hereafter acquired, in whole or in
part, by BOG, during the term hereof and otherwise upon and subject to the
provisions herein contained.

                                A G R E M E N T:

         FOR A GOOD AND VALUABLE CONSIDERATION, the receipt and sufficiency of
which are hereby acknowledged, BOG and Gasco hereby act, agree and covenant as
follows:

         Section 1.  DEFINED TERMS.  As used herein, the following terms shall
have the following meanings:

                 "Affiliate" means, with respect to any Person:  (a) any other
         Person directly or indirectly owning, controlling or holding with
         power to vote 10% or more of the outstanding voting securities of such
         Person, (b) any other Person 10% or more of whose outstanding voting
         securities are directly or indirectly owned, controlled or held with
         power to vote by such Person, and (c) any other Person directly or
         indirectly controlling, controlled by or under common control with
         such Person.

                 "Agreement Term" means the period beginning on March 1, 1997
         at 12:01 a.m. Dallas, Texas local time, and ending on the earlier to
         occur of (i) March 31, 1998, at 11:59 p.m. Dallas, Texas local time,
         or (ii) the date on which Gasco's 18% share of the Drilling Costs
         incurred in drilling the Subject Wells and Subsequent Wells equals or
         exceeds $4,500,000.00.  However, in the event that it reasonably
         appears to BOG that such $4,500,000.00 amount will be reached before
         March 31, 1998 based upon the Drilling Costs incurred to that point in
         time and BOG's estimate of future Drilling Costs, BOG shall give Gasco
         written notice that such amount will probably be reached before March
         31, 1998 and Gasco shall have the option to nonetheless extend the
         term of this Agreement to 11:59 p.m. Dallas, Texas local time on March
         31, 1998, by giving BOG written notice of such extension no less than
         fifteen (15) days after Gasco's receipt of BOG's notice.

                 "Applicable Environmental Laws" means any federal, state
         and/or local laws, rules, orders or regulations, whether now existing
         or hereafter enacted, modified or amended, relating to health or to
         the protection of the environment, including without limitation the
         Comprehensive Environmental Response, Compensation and Liability Act
         of 1980, as amended by the Superfund Amendments and Reauthorization
         Act of 1986, the Resource Conservation and Recovery Act of 1976, a
         amended by the Used Oil Recycling Act of 1980, the Solid Waste
         Disposal Act Amendments of 1980, and the Hazardous and Solid Waste
         Amendments of 1984.

                 "Assigned Interests" shall have the meaning assigned to it in
         Section 9 hereof.

                 "Assignment" means any assignment executed pursuant to Section
         9 hereof by BOG in favor of Gasco.
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                 "BOG Completion Costs" means, with respect to any particular
         Subject Well or Subsequent Well, BOG's share of the Completion Costs
         associated with such Subject Well or Subsequent Well.  For purposes of
         the foregoing, "BOG's share" of Completion Costs shall be determined
         based upon the share of Completion Costs allocable to BOG Properties
         (a) without regard to any other agreement whereunder a third party
         agrees to carry BOG for all or any portion of what would otherwise be
         BOG's share of Completion Costs relative to any particular Subject
         Well or Subsequent Well, (b) without regard to any agreement
         whereunder BOG agrees to carry a third party for a share of such third
         party's Completion Costs, and (c) with regard to and taking into
         account any additional interest (and attendant share of Completion
         Costs) in any particular Subject Well or Subsequent Well which BOG may
         acquire, temporarily or permanently, due to the election by one or
         more third parties not to participate in the Completion of such
         Subject Well or Subsequent Well, provided, however, that the interests
         that are the subject of such third party election not to participate
         shall be deemed to be part of the BOG Properties for the full term of
         the relinquishment of the interest by the third party in accordance
         with the terms of the agreement creating the temporary interest.  By
         way of illustration, assume that BOG owns (or is entitled to earn,
         under a BOG Farmout Agreement or otherwise) a 25% interest in a lease
         covering 100% of the mineral fee interest in Tract A, and ABC Oil
         Company ("ABC") owns 25% and CDE Oil Company ("CDE") owns the
         remaining 50% interest.  If BOG proposes the Completion of a Subject
         Well or Subsequent Well on Tract A and all of BOG, ABC and CDE elect
         to participate therein, BOG's share of the Completion Costs associated
         with such well would, in typical circumstances, be 25%.  If, however,
         ABC elects not to participate in the Completion of the well and BOG
         and CDE elect to proceed to Complete the well and each acquire a
         proportionate part of ABC's non-consent interest, BOG's share of the
         Completion Costs would, in typical circumstances, be 33.333%.  In the
         event ABC has the right to again participate in the well after, for
         example, payout of a nonconsent penalty, the interests of BOG and
         Gasco shall both proportionately be reduced to take into account the
         after payout interest of ABC.  In both of the examples set out above,
         assume further that XYZ Oil Company ("XYZ") has agreed to carry BOG
         for 50% of what would otherwise be BOG's share of Completion Costs in
         order to earn 25% of BOG's interest in the well.  Under such
         circumstances, the BOG Completion Costs shall be determined without
         regard to XYZ's agreement to pay 50% of what would otherwise be BOG's
         share of the Completion Costs associated with the well, but the 25%
         interest BOG is obligated to assign to XYZ shall be taken into account
         in determining the interest in any particular BOG Property subject to
         this Agreement.  As such, in this example in which XYZ has agreed to
         pay 50% of BOG's share of Completion Costs in return for 25% of BOG's
         interest in the Subject Well or Subsequent Well, as BOG's interest in
         the well is reduced to 18.75% in the example in which all of the
         parties elected to participate and to 24.99975% in the example in
         which ABC elected not to participate in order to account for XYZ's
         earned interest, the BOG Completion Costs associated with such well
         would be reduced to BOG's reduced interest in the Subject Well or
         Subsequent Well.

                 "BOG Drilling Costs" means, with respect to any particular
         Subject Well or Subsequent Well, BOG's share of the Drilling Costs
         associated with such Subject Well or Subsequent Well.  For purposes of
         the foregoing, "BOG's share" of Drilling Costs shall be determined
         based upon the share of Drilling Costs allocable to BOG Properties (a)
         without regard to any other agreement whereunder a third party agrees
         to carry BOG for all or any portion of what would otherwise be BOG's
         share of Drilling Costs relative to any particular Subject Well or
         Subsequent Well, (b) without regard to any agreement whereunder BOG
         agrees to carry a third party for a share of such third party's
         Drilling Costs, and (c) with regard to and taking into account any
         additional interest (and attendant share of additional Drilling Costs)
         in any particular Subject Well or Subsequent Well which BOG may
         acquire, temporarily or permanently, due to the election by one or
         more third parties not to participate in the drilling of such Subject
         Well or Subsequent Well, provided, however, that the interests that
         are the subject of such third party election not to participate shall
         be deemed to be part of the BOG Properties for the full term of the
         relinquishment of the interest by the third party in accordance with
         the terms of the agreement creating the temporary interest.  By way of
         illustration, assume that BOG owns (or is entitled to earn, under a
         BOG Farmout Agreement or otherwise) a 25% interest in a lease covering
         100% of the mineral fee interest in Tract A, and ABC Oil Company
         ("ABC") owns 25% and CDE Oil Company ("CDE") owns the remaining 50%
         interest.  If BOG proposes the drilling of a well on Tract A and all
         of BOG, ABC and CDE elect to participate therein, BOG's share of the
         Drilling Costs associated with such well would, in typical
         circumstances be 25%.  If, however, ABC elects not to participate in
         the drilling of the well and BOG and CDE elect to proceed to drill the
         well and each acquire their proportionate part of ABC's non-consent
         interest, BOG's share of the Drilling Costs would, in typical




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         circumstances, be 33.333%.  In the event ABC has the right to again 
         participate in the well after, for example, payout of a nonconsent 
         penalty, the interests of BOG and Gasco shall both proportionately    
         be reduced to take into account the after payout interest of ABC. 
         In both of the examples set out above, assume further that XYZ Oil
         Company ("XYZ") has agreed to carry BOG for 50% of what would
         otherwise be BOG's share of Drilling Costs in order to earn 25% of
         BOG's interest in the Subject Well or Subsequent Well.  Under such
         circumstances, the BOG Drilling Costs shall be determined without
         regard to XYZ's agreement to pay 50% of what would otherwise be BOG's
         share of the Drilling Costs associated with the well, but the 25%
         interest BOG is obligated to assign to XYZ shall be taken into account
         in determining  the interest in any particular BOG Property subject to
         this Agreement.  As such, in this example in which XYZ has agreed to
         pay 50% of BOG's share of Drilling Costs in return for 25% of BOG's
         interest in the Subject Well or Subsequent Well, as BOG's interest in
         the well is reduced to 18.75% in the example in which all of the
         parties elected to participate and to 24.99975% in the example in
         which ABC elected not to participate in order to account for XYZ's
         earned interest, the BOG Drilling Costs associated with such well
         would be reduced to BOG's reduced interest in the Subject Well or
         Subsequent Well.

                 "BOG Farmout Agreement" means any agreement through which BOG
         and/or Gasco must either provide seismic data, drill a Subject Well or
         drill a Subsequent Well in order to earn an assignment of BOG
         Properties from a third party.

                 "BOG Participation Agreements" means any agreements now or
         hereafter existing whereunder BOG agrees with certain third parties
         upon terms and conditions of joint exploration and/or development of
         oil and/or gas properties located in the domestic United States,
         including without limitation the existing participation agreements
         described in Exhibit A hereto, as same may be amended, modified or
         extended from time to time.

                 "BOG Properties" means BOG's undivided right, title and
         interest in and to any property, right or interest that gives BOG the
         right to drill for and produce oil, gas and associated hydrocarbons in
         any of the states set forth in Exhibit B attached hereto and any state
         bottom offshore lands and waters for the states listed in Exhibit B,
         whether now owned or hereafter acquired by BOG during the term hereof;
         BOG Properties shall in no event include any overriding royalty
         interest owned by or owing to BOG, whether pursuant to a BOG
         Participation Agreement or otherwise.   However, in the event that
         prior to the Completion of a Subject Well BOG has assigned or has
         agreed to assign interests in properties, rights or interests which
         are related to such Subject Well or the Drilling and Production Unit
         for the applicable Subject Well, the interests in such properties,
         rights or interests which BOG has assigned or agreed to assign shall
         not be part of the BOG Properties for purposes of this Agreement;
         provided, however, that in the event that BOG enters into an agreement
         with a third-party that is similar in form and substance as the terms
         of this Agreement (being for participation in at least the majority of
         all of the wells that are drilled by BOG over at least a six month
         period and being hereinafter referred to as a "Parallel Agreement" and
         which Parallel Agreement shall comply with the provisions of Section
         3(c) hereof), then in such event the interests BOG has agreed to
         assign to such third-party pursuant to the terms of the Parallel
         Agreement shall be deemed to be part of the BOG Properties for
         purposes of this Agreement.  In addition, anything to the contrary
         contained herein notwithstanding, in the event that BOG Drilling Costs
         with respect to any particular Subject Well are estimated, as set out
         in the initial authority for expenditure or "AFE" circulated for the
         drilling of such Subject Well (which AFE may be circulated by BOG or
         by some third party), to exceed $750,000.00, BOG's undivided interests
         in and to the properties, rights and interests included in the
         Drilling and Production Unit for such Subject Well shall be reduced in
         the same proportion which is necessary to cause the estimated BOG
         Drilling Costs (as reflected in the AFE) allocable to the BOG
         Properties to be reduced to $750,000.00, and the amount of the
         reduction shall not be a part of the BOG Properties and shall
         otherwise be excluded from this Agreement for all purposes.  By way of
         illustration, assume that (a) the estimated BOG Drilling Costs for any
         particular Subject Well is $1,000,000.00 and thus exceeds the amount
         of $750,000.00 by $250,000.00, (b) the Drilling and Production Unit
         for such Subject Well covers 80 acres and as part of the BOG
         Properties BOG owns and undivided 70% interest in an oil and gas lease
         (for purposes of this example referred to as the "Lease") covering 60
         net mineral acres in such Drilling Unit and an undivided 40% interest
         in the minerals (for purposes of this example referred to as the
         "Minerals") covering the other 20 net mineral acres in the Drilling
         and Production Unit.  Under this example, only 75% of BOG's interest
         in both the Lease and the Minerals would constitute




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         the BOG Properties for such Drilling and Production Unit; as such,
         only an undivided 52.5% (i.e. 75% of BOG's 70%) interest in the Lease
         and an undivided 30% (i.e. 75% of BOG's 40%) interest in the Minerals
         would be included the BOG Properties for the Drilling and Production
         Unit for such  Subject Well. Notwithstanding any provision hereof to
         the contrary,  the original estimate of BOG Drilling Costs as set
         forth in the  initial AFE circulated relative to any Subject Well will
         always, unless BOG and Gasco mutually agree to the contrary,
         definitely be utilized for purposes of determining whether and by how
         much the above-described $750,000.00 benchmark has been exceeded.

                 "Casing Point" means the time when the well has been drilled
         to the objective depth stated in the initial notice, appropriate tests
         have been made, and the drilling operator notifies all of the
         participating parties of his recommendation with respect to completing
         or plugging and abandoning the well.

                 "Complete" or "Completion" means a single operation designed
         to complete a Subject Well or Subsequent Well as a producer in one or
         more zones, including without limitation the setting of production
         casing, perforating, and, where necessary or appropriate, well
         stimulation.

                 "Completion Costs" means the costs and expenses associated
         with any attempted Completion of a Subject Well or Subsequent Well.
         In addition, in the event that Completion operations are attempted
         within a well but the well is not ultimately completed as a producer,
         the costs incurred to plug and abandon such well shall also constitute
         Completion Costs for purposes of this Agreement.

                 "Consent" means any right of a third party to grant or deny
         its consent to the execution of this Agreement or the consummation of
         all or any part of the transactions contemplated herein, including
         without limitation any consents provided for or otherwise disclosed in
         the existing BOG Participation Agreements.

                 "Drilling Costs" means all costs and expenses related to (a)
         the preparation for drilling and then the drilling and equipping of a
         well up and to Casing Point, and (b) all activities associated with
         plugging and abandoning a well in which Completion operations have not
         been attempted.  Without limitation of the generality of the
         foregoing, Drilling Costs shall include all costs associated with (i)
         clearing and building a location and creating or improving access to
         such location (e.g., by building roads), (ii) setting surface casing,
         and (iii) logging and testing the well prior to the commencement of
         Completion operations.

                 "Drilling and Production Unit" means, with respect to any
         particular well, the acreage allocable, as determined by reference to
         the formation initially Completed in such well, to such well under
         applicable laws, rules or regulations of governmental authorities
         having jurisdiction for the drilling and production of such well at a
         legal location and the production from such well of its maximum
         allowable, such maximum allowable to be determined by reference to the
         lesser of (a) the maximum permissible allowable for such well as set
         by any governmental authority having jurisdiction, and (b) such well's
         maximum prudent physical productive capability, as determined by
         reference to the initial potential test or initial deliverability
         test, as the case may be, for such well, limited in each instance to
         those depths between the surface and 100 feet below the deepest depth
         drilled in the relevant well; the exact configuration of any such
         Drilling and Production Unit shall be designated by BOG utilizing
         reasonable discretion and good faith.  In the event that no
         governmental authority having jurisdiction has promulgated any laws,
         rules or regulations pursuant to which the Drilling and Production
         Unit for any particular well can be determined as set forth in the
         immediately preceding sentence, BOG shall, utilizing reasonable
         discretion and good faith, designate a Drilling and Production Unit
         for such well.  However, in the event that after a Drilling and
         Production Unit is established for a Subject Well as provided herein,
         the Drilling and Production Unit for a Subject Well that has been
         completed as a producer is reconfigured or otherwise altered or
         changed under law, rule, order or regulation of any governmental
         authority having jurisdiction (which BOG agrees to neither apply for
         or support if an effect of such order would be to reduce the interest
         of Gasco in the applicable Drilling and Production Unit from that
         which existed when the Subject Well was drilled and completed),
         commencing with the effective date of such change, the Drilling and
         Production Unit for such Subject Well shall be deemed to have been
         altered as required by the law, rule, order or regulation and the
         Parties shall execute all conveyance instruments necessary to cause
         Gasco to own the interests (and only the interests) in the entirety of
         the BOG Properties which are included within the revised Drilling and
         Production Unit; provided, however, that in the event that





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         prior to the change in the Drilling and Production Unit a well has
         been drilled on acreage (or lands pooled or otherwise combined
         therewith) which was not previously included within such Drilling and
         Production Unit or BOG has assigned interests in acreage which was not
         previously included within such Drilling and Production Unit, BOG
         shall not be required to assign such well (or any production
         therefrom) or interests to Gasco despite the later inclusion of such
         well or acreage in the Drilling and Production Unit.  Similarly, in
         the event that prior to a change in a Drilling and Production Unit a
         Subsequent Well has been drilled on acreage which was previously
         included within such Drilling and Production Unit and Gasco
         participated in the drilling of such Subsequent Well as provided in
         Section 9(b) below, Gasco shall not be required to assign its interest
         in such Subsequent Well (or any production therefrom) to BOG despite
         the later exclusion of such Subsequent Well or acreage from the
         Drilling and Production Unit.  The Drilling and Production Unit for
         any particular Subject Well shall in no event include any acreage
         and/or depths otherwise allocable to the drilling and spacing,
         proration or pooled unit reasonably and in good faith designated by
         BOG for any other well, the actual drilling of which was commenced
         prior to the date hereof or which is the subject of the Previous
         Agreement, in which BOG owns an interest and which does not constitute
         a Subject Well.

                 "Initial Deposit" shall have the meaning assigned to it in
         Section 8 hereof.

                 "Initial Period" shall have the meaning assigned to it in
         Section 8 hereof.

                 "Person" means, an individual, corporation, partnership,
         limited liability company, association, joint stock company, pension
         fund, trust or trustee thereof, estate or executor thereof,
         unincorporated organization or joint venture, court or governmental
         unit or any agency or subdivision thereof, or any other legally
         recognizable entity.

                 "Preferential Rights" means a preferential right or option in
         favor of a third party to acquire all or a portion of a BOG Property,
         or to otherwise participate with BOG in the exploration, or
         development thereof.

                 "Pre-Payment Balance" means the balance of the funds that have
         been paid to BOG for Gasco's share of BOG Drilling Costs and BOG
         Completion Costs which have not yet been paid or advanced to the
         drilling operator.

                 "Routine Governmental Approvals" means the right of any
         governmental entity to consent to or approve the transfer of any
         interest in a specific BOG Property.

                 "Seismic Data" means all data secured by or on behalf of BOG
         in the conduct of 3-D seismic operations on, across or through the BOG
         Properties, including any tapes, reproducibles and interpretations.
         Seismic Data shall not include any data which BOG, in its sole and
         absolute discretion, deems to be subject to a confidentiality
         restriction imposed by or for the benefit of a third party.

                 "Shortfall Deposit" means any additional funds required to be
         deposited by Gasco with BOG pursuant to subsection 8(b)(iii) hereof.

                 "Subject Well" means each well on a BOG Property, or on lands
         pooled or unitized therewith, for which drilling operations are
         actually commenced after the commencement of  the Agreement Term and
         for which Gasco's share of the BOG Drilling Costs for such well have
         been forwarded to the drilling operator for such well prior to the
         expiration of the Agreement Term in accordance with the terms of
         Section 8 below, regardless of when the well was proposed; the term
         Subject Well shall not include (a) any well in the drilling of which
         BOG elects not to participate, or (b) any recompletion, deepening,
         side track, plug back, rework or other operation in a wellbore already
         in existence at the time the subject new operation is proposed.  For
         purposes of this definition, drilling operations for a well shall not
         be deemed to have been "actually commenced" unless and until a drill
         bit is turning in the ground at the well's surface location utilizing
         a drilling rig that is capable of drilling the well to its proposed
         total depth.  The Parties recognize and agree that any well which is
         drilled within the Drilling and Production Unit (or on lands pooled or
         unitized therewith) that is established for a well which was the
         subject of the Previous Agreement or for a well for which drilling
         operations were actually commenced prior to the Agreement Term, shall
         not be a Subject Well or Subsequent





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         Well for purposes of this Agreement and such a well shall not be
         subject to this Agreement, to the effect that Gasco shall not be
         obligated hereunder to pay any share of the Drilling Costs associated
         with any such well or wells and shall further have no right hereunder
         to receive assignment of any interest therein (or in any Drilling and
         Production Unit otherwise allocable thereto), except to the extent
         that such costs are to be paid and/or assignments are to be made under
         the terms of the Previous Agreement.  In addition, in the event that
         BOG and Gasco mutually so agree with respect to any particular well or
         wells proposed to be drilled during the Agreement Term, such well or
         wells shall not become Subject Wells and shall otherwise not be
         subject to this Agreement, to the effect that Gasco shall not be
         obligated to pay any share of the Drilling Costs associated with any
         such well or wells and shall further have no right to receive
         assignment of any interest therein (or in any Drilling and Production
         Unit otherwise allocable thereto).

                 "Subsequent Deposit" shall have the meaning assigned to it in
         Section 8 hereof.

                 "Subsequent Month" means the next occurring calendar month.

                 "Subsequent Well" shall have the meaning assigned to it in
         subsection 9(b) hereof.

         Section 2.  REPRESENTATIONS OF BOG.  BOG represents to Gasco that:

                 (a)      BOG is a limited partnership, duly formed and legally
         existing under the laws of the State of Delaware.  BOG has full power
         to enter into and perform its obligations under this Agreement and has
         taken all appropriate action to authorize entering into this Agreement
         and performance of its obligations hereunder.  Other than requirements
         (if any) that there be obtained Consents or waivers of Preferential
         Rights regarding the transfer of specific BOG Properties, and except
         for Routine Governmental Approvals which are customarily obtained
         post-closing and which BOG has no reason to believe cannot be
         obtained, neither the execution and delivery of this Agreement, nor
         the consummation of the transactions contemplated hereby, nor the
         compliance with the terms hereof, will result in any material default
         under any material agreement or instrument to which BOG is a party or
         by which the BOG Properties are bound, or violate any order, writ,
         injunction, decree, statute, rule or regulation applicable to BOG or
         to the BOG Properties.  This Agreement constitutes the legal, valid
         and binding obligation of BOG, enforceable in accordance with its
         terms, except as limited by bankruptcy or other laws applicable
         generally to creditor's rights and as limited by general equitable
         principles.

                 (b)      There are no suits, actions, claims, investigations,
         inquiries, proceedings or demands pending (or, to the best of BOG's
         knowledge, threatened) which affect the execution and delivery of this
         Agreement, the consummation of the transactions contemplated hereby,
         or the BOG Properties, other than as disclosed in Exhibit A.

                 (c)      BOG has not entered into, and shall not during the
         term of this Agreement enter into Parallel Agreements which would
         result in the assignment of more than 40% of BOG's undivided interest
         in the BOG Properties.

THE EXPRESS REPRESENTATIONS OF BOG CONTAINED IN THIS SECTION OR IN ANY
ASSIGNMENT EXECUTED PURSUANT HERETO ARE EXCLUSIVE AND ARE IN LIEU OF ALL OTHER
REPRESENTATIONS AND WARRANTIES, EXPRESS, IMPLIED, STATUTORY OR OTHERWISE, AND
BOG EXPRESSLY DISCLAIMS ANY AND ALL SUCH OTHER REPRESENTATIONS AND WARRANTIES.
WITHOUT LIMITATION OF THE FOREGOING, UNDIVIDED INTERESTS EARNED BY GASCO
HEREUNDER IN THE BOG PROPERTIES SHALL BE CONVEYED WITHOUT ANY WARRANTY OR
REPRESENTATION, WHETHER EXPRESS, IMPLIED, STATUTORY OR OTHERWISE, RELATING TO
THE CONDITION, QUANTITY, QUALITY, FITNESS FOR A PARTICULAR PURPOSE, CONFORMITY
TO THE MODELS OR SAMPLES OF MATERIALS OR MERCHANTABILITY OF ANY EQUIPMENT OR
ITS FITNESS FOR ANY PURPOSE AND GASCO SHALL ACCEPT ALL OF THE SAME IN THEIR "AS
IS, WHERE IS" CONDITION.  BOG MAKES NO WARRANTY OR REPRESENTATION, EXPRESS,
IMPLIED, STATUTORY OR OTHERWISE, AS TO THE ACCURACY OR COMPLETENESS OF ANY
DATA, INTERPRETATIONS, REPORTS, RECORDS, PROJECTIONS, INFORMATION OR MATERIALS
NOW,





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HERETOFORE OR HEREAFTER FURNISHED OR MADE AVAILABLE TO GASCO IN CONNECTION WITH
THIS AGREEMENT INCLUDING, WITHOUT LIMITATION, RELATIVE TO SEISMIC OR GEOLOGICAL
MATTERS, PRICING ASSUMPTIONS, OR QUALITY OR QUANTITY OF HYDROCARBON RESERVES
(IF ANY) ATTRIBUTABLE TO THE BOG PROPERTIES OR THE ABILITY OR POTENTIAL OF THE
BOG PROPERTIES TO PRODUCE HYDROCARBONS OR ANY OTHER MATTERS CONTAINED IN THE
PROPRIETARY DATA OR ANY OTHER MATERIALS FURNISHED OR MADE AVAILABLE TO GASCO BY
BOG OR BY BOG'S AGENTS OR REPRESENTATIVES.  ANY AND ALL SUCH DATA, RECORDS,
REPORTS, PROJECTIONS, INFORMATION AND OTHER MATERIALS (WRITTEN OR ORAL)
FURNISHED BY BOG OR OTHERWISE MADE AVAILABLE OR DISCLOSED TO GASCO ARE PROVIDED
GASCO AS A CONVENIENCE AND SHALL NOT CREATE OR GIVE RISE TO ANY LIABILITY OF OR
AGAINST BOG AND ANY RELIANCE ON OR USE OF THE SAME SHALL BE AT GASCO'S SOLE
RISK TO THE MAXIMUM EXTENT PERMITTED BY LAW.

         Section 3.  REPRESENTATIONS OF GASCO.  Gasco represents to BOG that:

                 (a)      Gasco is a limited partnership duly organized and
         legally existing under the laws of the State of West Virginia.  Gasco
         has full power to enter into and perform its obligations under this
         Agreement and has taken all appropriate action to authorize entering
         into this Agreement and performance of its obligations hereunder.
         Neither the execution and delivery of this Agreement, nor the
         consummation of the transactions contemplated hereby, nor the
         compliance with the terms hereof, will result in any default under any
         material agreement or instrument to which Gasco is a party or by which
         Gasco is bound, or violate any order, writ, injunction, decree,
         statute, rule or regulation applicable to Gasco.  This Agreement
         constitutes the legal, valid and binding obligation of Gasco,
         enforceable in accordance with its terms, except as limited by
         bankruptcy or other laws applicable generally to creditor's rights and
         as limited by general equitable principles.

                 (b)      There are no suits, actions, claims, investigations,
         inquiries, proceedings or demands pending (or, to the best of Gasco's
         knowledge, threatened) which affect the execution and delivery of this
         Agreement or the consummation of the transactions contemplated hereby.

                 (c)      Gasco is a knowledgeable purchaser, owner and
         operator of oil and gas properties, has the ability to evaluate (and
         in fact has evaluated or will evaluate, as the case may be) the BOG
         Properties for acquisition, and is acquiring the BOG Properties and
         its rights and interests hereunder for its own account and not with
         the present intent to make a distribution in violation of the
         Securities Act of 1933 as amended (and the rules and regulations
         pertaining thereto) or in violation of any other applicable securities
         laws, rules, or regulations.

         Section 4.  PREFERENTIAL RIGHTS AND CONSENTS.

         BOG will utilize reasonable efforts, consistent with industry
practices in transactions of this type, to identify any Preferential Rights or
Consents which would be applicable to the BOG Properties and the transactions
contemplated hereby.  In attempting to identify such Preferential Rights and
Consents, BOG is in no event obligated to go beyond its own records.  BOG shall
have no obligation other than to so attempt to identify such Preferential
Rights or Consents and to give the notices required by such identified
Preferential Rights or Consents prior to the drilling of a Subject Well or
Subsequent Well on the applicable BOG Properties.  To the extent a Preferential
Right applicable to any BOG Property (or portion thereof) is properly exercised
prior to the execution of an Assignment covering such BOG Property in favor of
Gasco, any well located or proposed to be located on the lands covered by such
BOG Property shall not be considered a Subject Well for purposes hereof, and
Gasco shall have no obligation to pay or bear any BOG Drilling Costs associated
therewith; any share of BOG Drilling Costs paid by Gasco relating to such well
prior to the exercise of the subject Preferential Right shall be reimbursed by
BOG to Gasco.  To the extent any Preferential Right applicable to any BOG
Property (or portion thereof) is identified after the date of an Assignment to
Gasco covering such BOG Property, and is further validly and properly exercised
by a third party or third parties after such date, Gasco shall convey the
specific BOG Property affected by such Preferential Right to the exercising
third party or third parties, and Gasco shall be entitled, as its sole remedy
against BOG, to a reimbursement of the 18% share of BOG Drilling Costs and 9%
share of BOG Completion Costs paid by Gasco with respect to the applicable
Subject Well or Subsequent Well which must be conveyed to such third party;
provided, however, that the amount of such reimbursement shall be
proportionately reduced in the event that less





                                      -7-
<PAGE>   8
than all of Gasco's interest in the BOG Property is required to be conveyed to
such third-party and BOG shall receive any and all consideration and/or
payments which are to be made by the third-party as a result of its exercise of
the Preferential Right.  BOG and Gasco hereby recognize that any Preferential
Right shall apply only to the specific property described in the instrument
creating same, and shall in no event be construed to apply to all, or any group
of, the BOG Properties, other than the specific property described in the
instrument creating the Preferential Right.  BOG shall use reasonable
commercial efforts to secure any Consent of which it becomes aware (whether
such Consent was identified before or after an Assignment was made covering the
BOG Property burdened by such Consent), and to the extent BOG so utilizes
reasonable commercial efforts, whether successful or not, Gasco shall have no
legal redress against BOG relating to any Consent (or the failure to obtain
same).  Prior to the drilling of each Subject Well, at Gasco's request, Gasco
will be given reasonable access, in BOG's offices, to BOG's copies of the
operating agreements and BOG Participation Agreements affecting the drilling of
such Subject Well.

         Section 5.  MAINTENANCE OF UNIFORM INTEREST PROVISIONS.

         It is hereby recognized that some of the BOG Properties may now be, or
hereafter become, subject to agreements (the "MUI Agreements") containing
maintenance of uniform interest provisions or similar restrictions against
assigning an interest in part, but less than all, of the contract area covered
by such agreement.  In this connection, BOG undertakes to use reasonable
commercial efforts to secure waivers from the other parties to each MUI
Agreement that will allow Assignments to be made hereunder.  In order to secure
these waivers, BOG may agree that any separate measurement and/or storage
facilities necessitated by an assignment by BOG to Gasco of an interest in
part, but less than all, of the contract area covered by the applicable MUI
Agreement shall be arranged and paid for in equal shares by BOG (50%) and Gasco
(50%).  BOG and Gasco further agree that any other costs, liabilities, damages
or obligations, of whatever kind or character,  arising out of or relative to
any maintenance of uniform interest or similar provision contained in an MUI
Agreement shall be borne and paid for in equal shares by BOG (50%) and Gasco
(50%).

         Section 6.  PARTICIPATION IN BOG DRILLING COSTS BY GASCO.

         Gasco shall have the obligation to fund 18% of the BOG Drilling Costs
associated with each Subject Well.  The election whether or not to participate
in the drilling of any particular well, and thus whether such well becomes a
Subject Well hereunder, will be exercised in the sole and absolute discretion
of BOG; upon an election by BOG to participate in the drilling of any
particular Subject Well, Gasco's obligation to pay 18% of the BOG Drilling
Costs associated with such Subject Well shall become absolute.  The Parties
recognize and agree that anything to the contrary contained herein
notwithstanding, in the event that Gasco's share of BOG Drilling Costs have
been forwarded to the drilling operator for a Subject Well prior to the
expiration of the Agreement Term, Gasco's responsibility to fund 18% of the BOG
Drilling Costs associated with such Subject Well shall continue despite the
termination of the Agreement Term.  If prior to the expiration of the Agreement
Term BOG has not furnished to the operator funds advanced to it by Gasco
pursuant to the terms hereof for the payment of BOG Drilling Costs with respect
to a Subject Well, and such Subject Well is for such reason not a well which
remains subject to this Agreement, BOG shall, within fifteen (15) days after
the expiration of the Agreement Term, refund to Gasco all funds advanced to it
regarding such well.

         Section 7.  COMPLETION ELECTIONS.

         Gasco shall have the obligation to fund 9% of the BOG Completion Costs
associated with each Subject Well.  In the event there is a separate Completion
point election relative to any particular Subject Well, BOG shall, in its sole
and absolute discretion, make such election for itself and for Gasco.  Any
election by BOG to Complete or not to Complete any Subject Well shall for all
purposes be binding upon Gasco, the same as if Gasco had also made the same
election.  Gasco shall have the obligation to fund a 9% share of all BOG
Completion Costs associated with any Subject Well.  The Parties recognize and
agree that anything to the contrary contained herein notwithstanding, in the
event that Gasco's share of BOG Drilling Costs have been forwarded to the
drilling operator for a Subject Well prior to the expiration of the Agreement
Term, Gasco's responsibility to fund 18% of the BOG Drilling Costs and 9% of
the BOG Completion Costs associated with such Subject Well shall continue
despite the termination of the Agreement Term.





                                      -8-
<PAGE>   9
         Section 8.  FUNDING AND PAYMENT OBLIGATIONS

                 (a)      Drilling Costs For March and April of 1997.

                          (i)  On or prior to the execution hereof, BOG has
                 provided to Gasco an estimate, based on BOG's best judgment,
                 of all BOG Drilling Costs related to Subject Wells for which
                 costs are estimated to be incurred or advanced between March
                 1, 1997 and April 30, 1997 (the "Initial Period").

                          (ii)  Contemporaneously with the execution of this
                 Agreement, Gasco shall forward to BOG two hundred ninety-four
                 thousand two hundred ten dollars ($294,210.00) (the "Initial
                 Deposit"), in readily available funds, representing the sum of
                 Gasco's 18% share of the estimated BOG Drilling Costs relating
                 to Subject Wells for the Initial Period estimated to be
                 incurred or advanced during the Initial Period.

                          (iii)  It is hereby recognized that the amount of the
                 Initial Deposit has been calculated based on estimated BOG
                 Drilling Costs relating to Subject Wells for the Initial
                 Period.  BOG shall have the right from time to time during the
                 Initial Period to revise its estimate of BOG Drilling Costs
                 relating to Subject Wells in the event that it reasonably
                 appears that the original estimate will be exceeded.  To the
                 extent that the Pre-Payment Balance is (or is reasonably
                 estimated by BOG to be) less at any particular time than the
                 sum of Gasco's 18% share of the revised estimate of BOG
                 Drilling Costs relating to Subject Wells for the Initial
                 Period, Gasco shall forward to BOG readily available funds
                 representing 18% of the portion of the estimated shortfall
                 attributable to BOG Drilling Costs relating to Subject Wells
                 (which funds shall constitute a Shortfall Deposit); such
                 Shortfall Deposit shall be made by Gasco, in immediately
                 available funds, within 15 days after receipt by Gasco of a
                 written request for the subject Shortfall Deposit.

                          (iv)  BOG shall pay when due, out of and to the
                 extent of the Initial Deposit and any Shortfall Deposit, the
                 share of BOG Drilling Costs relating to Subject Wells actually
                 incurred and charged to the account of Gasco.  The balance of
                 the Initial Deposit and any Shortfall Deposit which has not
                 been incurred and paid for Gasco's share of BOG Drilling Costs
                 will be applied against Gasco's share of the BOG Drilling
                 Costs relating to Subject Wells to be incurred and paid in the
                 next Subsequent Month; to the extent that the Pre-Payment
                 Balance is at the conclusion of the Initial Period (or any
                 Subsequent Month) more than the sum of Gasco's 18% share of
                 the estimate of BOG Drilling Costs and Completion Costs
                 relating to Subject Wells to be incurred and paid in the next
                 Subsequent Month, BOG shall promptly (and not later than 15
                 days after the beginning of such Subsequent Month) refund any
                 such excess to Gasco.

                 (b)      Drilling and Completion Costs During Subsequent
                 Months.

                          (i)  On or before the 25th day of each calendar month
                 preceding each Subsequent Month (other than March and April of
                 1997), BOG shall provide to Gasco a written estimate, based
                 upon BOG's best judgment, of the BOG Drilling Costs and BOG
                 Completion Costs relating to Subject Wells for such Subsequent
                 Month.

                          (ii)  On or before the first day of each Subsequent
                 Month, Gasco shall forward to BOG an amount (the "Subsequent
                 Deposit"), in readily available funds, representing the sum of
                 Gasco's 18% share of the estimated BOG Drilling Costs and
                 Gasco's 9% share of the estimated BOG Completion Costs
                 relating to Subject Wells for such Subsequent Month estimated
                 to be incurred or advanced during such Subsequent Month.  The
                 amount of each Subsequent Deposit shall, however, be
                 determined giving due credit to any Pre-Payment Balance that
                 is expected to remain unused from a previous period (i.e.,
                 from the Initial Period or a prior Subsequent Month, as the
                 case may be) and that further is not earmarked by BOG for
                 payment of Gasco's share of BOG Drilling Costs and/or BOG
                 Completion Costs relating to Subject Wells for such previous
                 period, which costs are reasonably expected to be paid during
                 the immediate Subsequent Month.





                                      -9-
<PAGE>   10
                          (iii)  It is hereby recognized that each Subsequent
                 Deposit shall be calculated based on estimated BOG Drilling
                 Costs and BOG Completion Costs relating to Subject Wells for
                 the applicable Subsequent Month.  BOG shall have the right
                 from time to time during each Subsequent Month to revise its
                 estimates of BOG Drilling Costs and/or BOG Completion Costs
                 relating to Subject Wells for such Subsequent Month upward in
                 the event that it reasonably appears that the original
                 estimates will be exceeded. To the extent that the Pre-Payment
                 Balance is (or is reasonably estimated by BOG to be) less at
                 any particular time than the sum of Gasco's 18% share of the
                 revised estimate of BOG Drilling Costs and Gasco's 9% share of
                 the revised estimate of BOG Completion Costs relating to
                 Subject Wells for the applicable Subsequent Month, Gasco shall
                 forward to BOG readily available funds (which shall constitute
                 a Shortfall Deposit) representing Gasco's share of the
                 estimated shortfall attributable to BOG Drilling Costs and BOG
                 Completion Costs relating to Subject Wells (such deposit shall
                 be made by Gasco, in immediately available funds, within 15
                 days after receipt by Gasco of a written request for the
                 Shortfall Deposit);  to the extent that the unexpended amount
                 of such Subsequent Deposit is at the conclusion of such
                 Subsequent Month more than the sum of Gasco's 18% share of the
                 estimate of BOG Drilling Costs and Gasco's 9% share of the
                 estimate of BOG Completion Costs relating to Subject Wells to
                 be incurred and paid in the next Subsequent Month, BOG shall
                 promptly (and not later than 15 days after the beginning of
                 such Subsequent Month) refund any such excess to Gasco.

                          (iv)  During each Subsequent Month BOG shall pay when
                 due, out of and to the extent of the Subsequent Deposit and
                 any Shortfall Deposit, the share of BOG Drilling Costs and BOG
                 Completion Costs relating to Subject Wells actually incurred
                 and charged to the account of Gasco during such Subsequent
                 Month.  The balance of the Subsequent Deposit and any
                 Shortfall Deposit which has not been incurred and paid for
                 Gasco's share of BOG Drilling Costs and BOG Completion Costs
                 will be applied against Gasco's share of the BOG Drilling
                 Costs and BOG Completion Costs relating to Subject Wells to be
                 incurred and paid in the next Subsequent Month;  to the extent
                 that the unexpended amount of such Subsequent Deposit is at
                 the conclusion of such Subsequent Month more than the sum of
                 Gasco's 18% share of the estimate of BOG Drilling Costs and
                 Gasco's 9% share of BOG Completion Costs relating to Subject
                 Wells to be incurred and paid in the next Subsequent Month,
                 BOG shall promptly (and not later than 15 days after the
                 beginning of such Subsequent Month) refund any such excess to
                 Gasco.

                 (c)      Reporting.  On or before a date that is Forty-five
         (45) days after expiration of each calendar quarter occurring within
         the Agreement Term, BOG shall provide to Gasco a statement reflecting,
         on a well-by-well basis, application of the funds attributable to
         Gasco's share of BOG Drilling Costs relating to Subject Wells and BOG
         Completion Costs relating to Subject Wells for the previous calendar
         quarter; such statement shall be based on actual numbers, where
         available, and on estimates, where actuals are not available.

         Section 9.   ASSIGNMENTS AND SUBSEQUENT WELLS.

                 (a)  Assignments.  BOG shall execute an Assignment in favor of
         Gasco covering each Subject Well that is Completed as a producer of
         oil, gas and/or associated hydrocarbons; any such Assignment shall be
         made on or before the later to occur of (i) thirty business days after
         the date the Subject Well was Completed, and (ii) thirty business days
         after BOG secures assignment from a third party of all or any portion
         of the interest in the Subject Well it is obligated to assign to Gasco
         hereunder.  Under each Assignment, BOG shall assign to Gasco an
         undivided 9% interest in and to the BOG Properties related to (A) the
         wellbore of any particular Subject Well that is Completed as a
         producer of oil, gas and/or associated hydrocarbons, and in and to the
         right to produce oil, gas and/or associated hydrocarbons therefrom,
         and (B) subject to the limitations and restrictions set forth in
         subsection 9(b), below, the Drilling and Production Unit allocable to
         such Subject Well.  Each Assignment shall be made effective on or
         before the date of first production from the Subject Well under
         instrument in substantially the form attached hereto as Exhibit C.
         Notwithstanding any provision hereof to the contrary, BOG shall not be
         obligated to execute any Assignment to Gasco hereunder if Gasco has
         failed to fund the BOG Drilling Costs or BOG Completion Costs for any
         Subject Well(s) in accordance with the provisions of Section 8 above;
         provided, however, that such Assignments shall not be withheld if
         there is a reasonable good faith dispute as to the accuracy of the
         invoice related to the amount of the BOG Drilling Costs or BOG
         Completion Costs which have not been paid and Gasco has paid any part
         of such BOG





                                      -10-
<PAGE>   11
         Drilling Costs and BOG Completion Costs which are not in good faith 
         dispute. The interest assigned to Gasco under any Assignment (the 
         "Assigned Interests") shall be burdened by an overriding royalty
         interest in favor of BOG (the "BOG ORRI") in the same proportions as
         the interests of the participants under the BOG Participation
         Agreement(s) relating to such Assigned Interests are burdened by an
         overriding royalty interest created or reserved in favor of BOG
         pursuant to the applicable BOG Participation Agreement(s).  The BOG
         ORRI shall be calculated in the same manner, and shall bear the same
         costs, expenses and taxes, as the overriding royalty interest of BOG
         burdening the interests of the other participants under the BOG
         Participation Agreements; provided, however, that in the event that
         the BOG ORRI would reduce Gasco's net revenue interest in any of the
         BOG Properties included within the Drilling and Production Unit of a
         Subject Well below 75%, proportionately reduced to Gasco's interest in
         the BOG Properties, with respect to those BOG Properties the amount of
         the BOG ORRI shall be reduced to an amount that is equal to the
         positive difference, if any, between 25% and the total of all existing
         royalty and overriding royally interests burdening such BOG
         Properties.  Any Assigned Interests shall further bear their
         proportionate share of any (i) rights of reversion or conversion in
         favor of third parties that do or may result in the reduction of BOG's
         interest in the Assigned Interests or the alteration of such interest
         (e.g. a back-in right under a BOG Farmout Agreement), and (ii)
         royalties, overriding royalties, production payments and any other
         burdens against BOG's interest in, or share of production from, the
         Assigned Interests, to the extent same are in existence or owing under
         documentation in existence as of the date the Assignment is made.

                 (b)  Subsequent Wells.  Any well drilled or commenced to be
         drilled, whether during or at any time after expiration of the
         Agreement Term, on acreage and to depths included within the Drilling
         and Production Unit (or on lands pooled or unitized therewith) for a
         Subject Well shall be considered a "Subsequent Well" for all purposes
         hereof.  Notwithstanding any provision hereof to the contrary:

                          (i)  In the event that both Gasco and BOG elect to
                 participate under the applicable BOG Participation Agreement,
                 joint operating agreement or similar agreement governing joint
                 operations on any Drilling and Production Unit in the drilling
                 of any particular Subsequent Well, Gasco shall have the
                 obligation to fund the sum of (A) 9% of BOG's share of all
                 Drilling Costs associated with such Subsequent Well (the "BOG
                 Carry Amount") and (B) Gasco's own share of the Drilling Costs
                 associated with such Subsequent Well.  Upon an election by
                 both Gasco and BOG to participate in the drilling of any
                 particular Subsequent Well, Gasco's obligation to pay all BOG
                 Carry Amounts associated with such Subsequent Well shall
                 become absolute.  Gasco shall pay over to BOG all BOG Carry
                 Amounts if and when incurred by BOG; provided that Gasco shall
                 have 15 business days after receipt from BOG of an invoice for
                 any particular BOG Carry Amounts to submit payment for same,
                 in immediately available funds, to BOG.

                          (ii)  In the event that Gasco fails to timely pay any
                 BOG Carry Amount within 15 days of Gasco's receipt of written
                 notice of such default from BOG, and the amount of such
                 deficiency exceeds $5,000.00, in addition to, and without
                 limitation of any remedies that may be available to BOG at law
                 or in equity, at BOG's option Gasco shall automatically and in
                 perpetuity forfeit to BOG all of Gasco's right, title and
                 interest, whether legal or equitable, vested or contingent, in
                 and to the entire wellbore of the Subsequent Well to which
                 such BOG Carry Amount relates, together with any right to oil,
                 gas or other substances that may be produced therefrom and any
                 proceeds related thereto, free and clear of any liens or
                 encumbrances created by, through or under Gasco, but not
                 otherwise, and subject to any superior rights of third parties
                 under any BOG Participation Agreement, joint operating
                 agreement or other agreement governing joint operations on the
                 relevant Drilling and Production Unit to which both Gasco and
                 BOG are parties or are otherwise bound.  However, in the event
                 that there is a reasonable good faith dispute as to whether an
                 invoiced BOG Carry Amount is accurate or otherwise due
                 hereunder and Gasco has paid any part of such BOG Carry Amount
                 which is not in good faith dispute, Gasco shall not be
                 required to forfeit its right, title and interest in and to
                 the Subsequent Well as otherwise provided in this Section
                 9(b)(ii).

                          (iii) Notwithstanding any provision hereof to the
                 contrary, in the event that any particular Subsequent Well has
                 allocated to it a drilling and spacing unit or a proration or
                 pooled unit, as the case may be, that includes acreage outside
                 the areal confines of the Drilling and Production Unit related
                 to





                                      -11-
<PAGE>   12
                 such Subsequent Well (the "Outside Lands"), Gasco shall in no
                 event be entitled to any right, title or interest in (A) any
                 such Outside Lands, or (B) any production or proceeds
                 allocable to such Outside Lands under applicable law, rule,
                 order or regulation or otherwise under any voluntary pooling,
                 unitization or similar agreement to which BOG is a party or is
                 otherwise bound; instead, Gasco shall be limited to its share
                 of production (or the proceeds thereof) as derived from its
                 right, title and interest only in the pooled unit, drilling
                 and spacing unit or proration unit, as the case may be, that
                 is made up of lands from the Drilling and Production Unit.
                 Further, BOG's share of Drilling Costs utilized in the
                 computation of BOG Carry Amounts shall be determined only by
                 reference to the proportionate share of any pooled unit,
                 drilling and spacing unit or proration unit, as the case may
                 be, that is made up of lands included in the Drilling and
                 Production Unit.  By way of example, assume that a particular
                 Drilling and Production Unit is comprised of Tract A,
                 containing 320 acres, and Tract B, containing 320 acres; Gasco
                 owns a 9% share of the oil, gas and other mineral leasehold
                 interest in Tracts A and B and BOG owns the remaining 91%.
                 Further assume that a Subsequent Well is drilled on Tract A,
                 and both Gasco and BOG elect to participate in the drilling of
                 such well.  Tract A, constituting Drilling and Production Unit
                 lands, is then pooled or otherwise combined with Tract C,
                 constituting Outside Lands; BOG owns a 100% interest in the
                 oil, gas and/other mineral leasehold interest in Tract C.
                 BOG's share of the Drilling Costs for the Subsequent Well is
                 $1,000,000.  Under these facts, Gasco would be entitled to
                 4.5% (i.e. 9% of 50%) of the production and allocable proceeds
                 from the subject Subsequent Well, prior to deduction of
                 royalties and other burdens, assuming production is allocable
                 as between Tracts A and B equally (i.e., on a surface acreage
                 basis); if production is allocable as between Tracts A and C
                 other than on a surface acreage basis (e.g., based on
                 acre-feet), then Gasco's share of production from the
                 Subsequent Well, again derived only from its 9% interest in
                 Tract A, will be adjusted accordingly.  Gasco's allocable
                 share of Drilling Costs under these facts would be $90,000
                 (i.e., the sum of (a) 9% x 50% x $1,000,000, and (b) the BOG
                 Carry Amount, which is 9% x 50% x $1,000,000), assuming that
                 Drilling Costs are allocable as between Tracts A and B on a
                 surface acreage basis; if Drilling Costs are allocable other
                 than on a surface acreage basis, Gasco's allocable share
                 thereof, again delivered from both its 9% interest in Tract A
                 and from its obligation to pay and bear the BOG Carry Amount,
                 shall be adjusted accordingly.

                          (iv)  The provisions of this subsection 9(b) shall be
                 binding upon and shall enure to the benefit of BOG and Gasco,
                 and their respective successors and assigns.  Any assignment
                 or other transfer by Gasco of any right, title or interest in
                 any Drilling and Production Unit established pursuant to this
                 Agreement shall be made expressly subject to the terms of this
                 subsection 9(b), and the transferee shall expressly agree to
                 assume and be bound by the terms of this subsection 9(b); any
                 attempted assignment or other transfer by Gasco that is not in
                 compliance with the foregoing shall be void.

         Section 10.  CONDITIONS PRECEDENT TO BOG PERFORMANCE AND TERMINATION
RIGHTS.

         The obligation of BOG under this Agreement to allow Gasco to
participate in the drilling of any particular Subject Well, and to receive
assignment of an undivided 9% of BOG's interest therein, is subject to the
fulfillment of each of the following conditions, unless any one or more of same
are waived, in whole or in part, by BOG:

                 a.       Each and every representation of Gasco under this
         Agreement shall be true and accurate in all material respects as of
         the date when made and shall be deemed to have been made again at and
         as of the time of the proposed drilling of each Subject Well, and
         shall at and as of the proposed drilling of each Subject Well be true
         and accurate in all material respects except as to changes
         specifically contemplated by this Agreement or consented to by BOG.

                 b.       Gasco shall have performed and complied in all
         material respects with (or compliance therewith shall have been waived
         by BOG) each and every covenant, agreement and condition required by
         this Agreement to be performed or complied with by Gasco, including
         without limitation Gasco shall have timely performed its funding and
         payment obligations under Section 8 hereof.

                 c.       No suit, action or other proceedings shall, on the
         date of the proposed drilling of each Subject Well, be pending or
         threatened against Gasco or BOG before any court or governmental
         agency seeking to





                                      -12-
<PAGE>   13
         restrain, prohibit, or obtain damages or other relief in connection
         with the consummation of the transactions contemplated by this
         Agreement, except to the extent that such suit, action or other
         proceedings arise, in whole or in part out of any action or inaction
         of BOG in breach of or otherwise in derogation of this Agreement.

Notwithstanding any provision hereof to the contrary, in the event Gasco fails
at any time or from time to time, within 15 days after receipt of written
notice of default from BOG, to make any payment owing to BOG hereunder or to
otherwise satisfy any funding obligation hereunder, and the amount of such
deficiency exceeds $5,000.00 in amount, in addition to and without limitation
of any and all other rights and remedies BOG may have in law or in equity for
such breach, BOG shall have the right, exercisable in its sole and absolute
discretion, to terminate this Agreement.

         Section 11.  CONDITIONS PRECEDENT TO GASCO PERFORMANCE.

         The obligation of Gasco under this Agreement to fund BOG Drilling
Costs and BOG Completion Costs for the drilling of Subject Wells as set forth
in Section 8 above, is subject to the fulfillment of each of the following
conditions, unless any one or more of same are waived, in whole or in part, by
Gasco:

                 a.       BOG shall have performed and complied in all material
         respects with (or compliance therewith shall have been waived by
         Gasco) each and every covenant, agreement and condition required by
         this Agreement to be performed or complied with by BOG.

                 b.       No suit, action or other proceedings shall, on the
         date for funding as set forth in Section 8, be pending or threatened
         against Gasco or BOG before any court or governmental agency seeking
         to restrain, prohibit, or obtain damages or other relief in connection
         with the consummation of the transactions contemplated by this
         Agreement, except to the extent that such suit, action or other
         proceedings arise, in whole or in part out of any action or inaction
         of Gasco in breach of or otherwise in derogation of this Agreement.

         Section 12. ASSUMPTION AND REIMBURSEMENT.

         Any assignment made by BOG to Gasco hereunder shall be made expressly
subject to any applicable BOG Participation Agreement(s), and any joint
operating agreements related thereto.  Gasco agrees to be bound by the terms of
any such BOG Participation Agreement(s) and any related joint operating
agreements, insofar as they apply to any Assigned Interests and related
facilities, and Gasco hereby agrees, effective as of the effective time of the
subject Assignment, to expressly assume a 9% share of BOG's obligations under
the applicable BOG Participation Agreements and joint operating agreement(s),
insofar as they pertain to the particular Assigned Interests and any related
facilities.  Nothing contained in this Section 12 or elsewhere in this
Agreement or any Assignment executed pursuant hereto shall be construed to
afford Gasco any right (and Gasco shall have no right) to participate in
production from or proceeds attributable to any well, other than a Subject Well
or a Subsequent Well, whether drilled under the terms of any particular BOG
Participation Agreement and/or joint operating agreement or otherwise.  In
addition, nothing contained in this Section 12 or elsewhere in this Agreement
or any Assignment executed pursuant hereto shall be construed to afford Gasco
any right (and Gasco shall have no right) to participate, as the result of the
operation of an area of mutual interest or similar provision, in any interests
acquired by third party participants under any BOG Participation Agreement or
joint operating agreement.

         Section 13.  INDEMNIFICATIONS.

                 (a)      INDEMNIFICATIONS BY BOG.  BOG agrees to indemnify and
         hold harmless Gasco and its officers, directors, employees, agents,
         and representatives from and against any and all claims, obligations,
         actions, liabilities, damages, or expenses of any kind or character
         arising out of or resulting from any agreement, arrangement or
         understanding alleged to have been made by, or on behalf of, such
         party with any broker or finder in connection with this Agreement or
         the transactions contemplated hereby.





                                      -13-
<PAGE>   14
                 (b)      INDEMNIFICATIONS BY GASCO.

                          (i)  GENERAL AND ENVIRONMENTAL.  NOTWITHSTANDING ANY
                 PROVISION HEREOF TO THE CONTRARY, GASCO SHALL, FROM AND AFTER
                 THE EFFECTIVE DATE OF EACH ASSIGNMENT, AGREE TO INDEMNIFY AND
                 HOLD BOG, ITS OFFICERS, DIRECTORS, EMPLOYEES, AGENTS AND
                 REPRESENTATIVES (HEREIN COLLECTIVELY CALLED THE "BOG
                 INDEMNIFIED PARTIES") HARMLESS FROM AND AGAINST ANY AND ALL
                 CLAIMS, OBLIGATIONS, ACTIONS, LIABILITIES, DAMAGES, OR
                 EXPENSES, INCLUDING WITHOUT LIMITATION COURT COSTS AND
                 ATTORNEYS' FEES (HEREIN COLLECTIVELY CALLED "CLAIMS"), TO THE
                 EXTENT SUCH CLAIMS AROSE OUT OF THE PHYSICAL CONDITION,
                 OWNERSHIP AND/OR OPERATION OF THE BOG PROPERTIES COVERED BY
                 THE SUBJECT ASSIGNMENT AT ANY TIME AFTER THE COMMENCEMENT OF
                 OPERATIONS FOR THE DRILLING OF THE SUBJECT WELL WHICH RESULTED
                 IN SUCH ASSIGNMENT, INCLUDING, WITHOUT LIMITATION, ANY CLAIMS
                 ARISING UNDER, OR AS A RESULT OF VIOLATION OF, APPLICABLE
                 ENVIRONMENTAL LAWS, WHETHER DUE, IN WHOLE OR IN PART, TO THE
                 NEGLIGENCE OR STRICT LIABILITY OF BOG, OTHER THAN GROSS
                 NEGLIGENCE OR WILLFUL MISCONDUCT.  THE PARTIES RECOGNIZE,
                 ACKNOWLEDGE AND AGREE THAT GASCO'S OBLIGATIONS AND
                 RESPONSIBILITIES UNDER THIS SECTION 13(b)(i) TO INDEMNIFY AND
                 HOLD THE BOG INDEMNIFIED PARTIES HARMLESS SHALL BE
                 PROPORTIONATELY REDUCED TO THE PERCENTAGE INTEREST IN THE
                 SUBJECT BOG PROPERTIES WHICH IS ASSIGNED OR TO BE ASSIGNED TO
                 GASCO UNDER THE TERMS OF THIS AGREEMENT.

                          (ii)    COMMISSIONS.  Gasco agrees to indemnify and
                 hold harmless BOG and the other BOG Indemnified Parties, from
                 and against any and all claims, obligations, actions,
                 liabilities, damages, or expenses of any kind or character
                 arising out of or resulting from any agreement, arrangement or
                 understanding alleged to have been made by, or on behalf of,
                 such party with any broker or finder in connection with this
                 Agreement or the transactions contemplated hereby.

         Section 14.  WELL DATA AND INFORMATION.

         For each Subject Well, BOG shall provide Gasco with the following: (i)
one copy of the AFE submitted for the Subject Well with an estimated working
interest and net revenue interest break down; (ii) one copy of the Exhibit A to
the final Joint Operating Agreement governing the drilling of such Subject Well
or any other document or instrument upon which BOG bases its allocation of
costs and expenses regarding such Subject Well; (iii) one copy of each drilling
and completion report received by BOG for the Subject Well; (iv) one copy of
each well log received by BOG for the Subject Well; and (v) all data and
information received regarding the testing and analysis of the well.  With
respect to each Subject Well which is completed as a producer, following the
completion of such Subject Well BOG shall provide Gasco with a copy of each of
the following documents which are in BOG's possession (i) the BOG Participation
Agreements which affect Gasco's interests in the Drilling and Production Unit
for the Subject Well, (ii) the operating agreements which govern the Drilling
and Production Unit for the Subject Well, and (iii) a copy of each oil and gas
lease and farm-in agreement which covers minerals which are located within the
Drilling and Production Unit for the Subject Well; provided, however, that
Gasco shall reimburse BOG for any third party copying charges which are
incurred to generate such copies.  In addition, with respect to each Subject
Well which is completed as a producer, subject to any contractual restrictions
that are placed on such interpretations pursuant to the terms of the applicable
BOG Participation Agreement(s) or the applicable seismic acquisition agreement,
BOG shall provide Gasco with one copy of a 3-D interpretational map generated
from Seismic Data by BOG for each of the targeted zone(s) in such Subject Well
(if a 3-D interpretational map has been generated by BOG for such zone),
limited in geographical extent to 1/2 mile of the outside perimeter of the
Drilling and Production Unit for the Subject Well.  Under no circumstances
shall Gasco acquire any ownership interest or license in any of the Seismic
Data.





                                      -14-
<PAGE>   15
         Section 15.  TITLE REVIEW.

         To the extent that it is within BOG's control, BOG agrees that a
reasonable title examination shall be performed for each Subject Well prior to
the commencement of actual drilling operations for such Subject Well.

         Section 16.  NON-COMPETE.

         During the Agreement Term and continuing for a period of 5 years
thereafter, unless BOG agrees in writing otherwise, except as provided in this
Agreement, neither Gasco, nor any Affiliate of Gasco, nor any broker or other
representative acting on behalf of Gasco shall own, purchase or otherwise
acquire any interest in the oil, gas and/or other minerals in, under or that
may be produced from any lands located within any of the following described
lands (hereinafter collectively referred to as the "Non-Compete Lands"): (1)
any lands located within one mile of the outside perimeter of the drilling
and/or proration units which are established for each Subject Well; and (2) the
lands which must be the subject of a non-compete agreement as the result of the
disclosure of 3-D interpretational maps or the assignment of interests in BOG
Properties pursuant to the terms of a BOG Participation Agreement which is
applicable to BOG Properties which are to be assigned to Gasco pursuant to the
terms of this Agreement.  The interests Gasco is precluded hereunder from
owning or acquiring include leasehold working interests, mineral fee interests
or servitudes, overriding royalty interests, royalty interests, production
payments, net profits interests, and any other interests, whether similar or
dissimilar, in the oil, gas and/or other minerals in, under or that may be
produced from any part of the Non-Compete Lands.  In the event that Gasco, any
Affiliate of Gasco or any broker or other representative acting on behalf of
Gasco or any Affiliate of Gasco owns or acquires any interest in breach of this
Section 16, BOG shall, in addition to any other remedies it may have at law or
in equity, have the right, exercisable in its sole discretion, to secure from
Gasco, an Affiliate of Gasco and/or any broker or other representative acting
on behalf of Gasco or any Affiliate of Gasco, as the case may be, an
assignment, free of all cost and expense, covering the entire interest so owned
or acquired in breach of this Section 16.  The provisions of this Section 16
shall survive the expiration of the Agreement Term and any earlier termination
of this Agreement.  Anything to the contrary contained in this Section 16
notwithstanding, the parties hereto agree that Gasco shall not be precluded
from acquiring interests from a third party which is a party to a BOG
Participation Agreement, provided that the interest acquired by Gasco from such
third party is subject to the BOG Participation Agreement to which such third
party is a party.  In addition, anything to the contrary contained in this
Section 16 notwithstanding, the parties hereto agree that Gasco shall not be
precluded from acquiring interests that have been acquired under a Parallel
Agreement, provided that the interest acquired by Gasco from such third party
is subject to the Parallel Agreement to which such third party is a party

         Section 17.  ACCOUNTING MATTERS.

         On or before a date that is 30 calendar days after the earlier of
expiration of the Agreement Term or termination of this Agreement under Section
10 or Section 11 hereof, BOG shall issue to Gasco a statement reflecting the
Pre-Payment Balance as of the statement date.  Along with said statement, BOG
shall, subject to any right of set-off afforded BOG hereunder, return to Gasco
the Pre-Payment Balance, less that portion which BOG believes should be
retained by BOG in order to satisfy Gasco's share of any BOG Drilling Costs or
BOG Completion Costs still to be paid or incurred hereunder.  On or before a
date that is 120 calendar days after the earlier of expiration of the Agreement
Term or termination of this Agreement under Section 10 or Section 11 hereof,
BOG shall return, subject to any right of set-off afforded BOG hereunder, to
Gasco any of the remaining Pre-Payment Balance, to the extent it exceeds an
amount sufficient to cover Gasco's share of any then-accrued BOG Drilling Costs
or BOG Completion Costs.

         Section 18.  INSURANCE.

         Gasco agrees to be bound by any election made by BOG concerning
insurance coverage relative to any particular Subject Well, and Gasco shall pay
a 9% share of what would otherwise be BOG's insurance costs relative to such
Subject Well and any related facilities.  Prior to execution of an Assignment
covering such Subject Well, BOG shall make any insurance elections for and on
behalf of Gasco, and such election shall be binding upon Gasco, the same as if
made by Gasco.  For example, if BOG elects to be covered by the operator's
insurance relative to any particular Subject Well, so will Gasco and if BOG
decides to secure or utilize its own insurance coverage relative to





                                      -15-
<PAGE>   16
any particular Subject Well, Gasco's interest in the Subject Well shall also
rely upon such insurance coverage; Gasco shall pay a 9% share of BOG's costs in
securing insurance coverage relative to any particular Subject Well.  If BOG
decides to secure or utilize its own insurance coverage relative to a Subject
Well, Gasco will be named as an additional insured in the certificate issued
for such coverage.

         Section 19.  NOTICES.

         All notices and other communications required under this Agreement
shall (unless otherwise specifically provided herein) be in writing and be
delivered personally, by recognized commercial courier or delivery service
(which provides a receipt), by telex or telecopier (with receipt acknowledged),
or by registered or certified mail (postage prepaid), at the following
addresses:

         If to Gasco:
                 194 Summers Street, 2nd Floor
                 Charleston, W.V.  25301
                 Facsimile # (304) 344-2467
                 Attention:  Mr. J. S. Stevens, III

         If to BOG:
                 Brigham Oil & Gas, L.P.
                 5949 Sherry Lane, Suite 1616
                 Dallas, Texas  75225
                 Facsimile # (214) 360-9825
                 Attention:  Mr. Bud Brigham

and shall be considered delivered on the date of receipt.  Either Gasco or BOG
may specify as its proper address any other post office address within the
continental limits of the United States by giving notice to the other party, in
the manner provided in this Section, at least two (2) business days prior to
the effective date of such change of address.

         Section 20.  SURVIVAL OF PROVISIONS.

         All representations, warranties and indemnifications made herein by 
BOG or Gasco shall survive in perpetuity the expiration of the Agreement Term
and any termination hereof under Section 10 or Section 11.

         Section 21.  DISCLAIMERS AND ELECTIONS.

         The liabilities of the parties hereunder shall be several, not joint or
collective.  It is not the intention of the parties to create, nor shall this
Agreement be deemed as creating, a joint venture, or a mining, tax or other
partnership or association or to render the parties liable as partners.
However, solely for purposes of income taxation and reporting of income taxes,
the parties agree that the relationship under this Agreement shall be
considered as a tax partnership in accordance with the provisions of the Tax
Partnership Agreement which is attached hereto as Exhibit D.

         Section 22.  MISCELLANEOUS MATTERS.

                 a.   Neither Gasco nor BOG shall assign or otherwise transfer 
         any rights, interests or obligations under this Agreement to any
         third party without first obtaining the written consent of the other,
         which consent may be either granted or withheld in the sole and
         absolute discretion of the party being asked to grant consent; provided
         that either of BOG or Gasco may freely transfer or otherwise dispose of
         all of its rights, interests and obligations hereunder (i) by sale or
         other transfer or disposition of all or substantially all of its assets
         (whether or not covered hereby) to an Affiliate or (ii) otherwise by
         merger, reorganization or consolidation.  This Agreement shall be
         binding upon and shall enure to the benefit of Gasco and BOG and their
         respective permitted successors and assigns.





                                      -16-
<PAGE>   17
                 b.   Each party shall bear and pay all expenses (including
         without limitation attorneys' fees) incurred by it in connection with
         the transaction contemplated by this Agreement.

                 c.   This Agreement contains the entire understanding of the
         parties hereto with respect to subject matter hereof and supersedes
         all prior agreements, understandings, negotiations, and discussions
         among the parties with respect to such subject matter.  The
         descriptive headings contained in this Agreement are for convenience
         only and shall not control or affect the meaning or construction of
         any provision of this Agreement.  Within this Agreement words of any
         gender shall be held and construed to cover any other gender, and
         words in the singular shall be held and construed to cover the plural,
         unless the context otherwise requires.  Time is of the essence in this
         Agreement.

                 d.   This Agreement may be amended, modified, supplemented,
         restated or discharged (and provisions hereof may be waived) only by
         an instrument in writing signed by the party against whom enforcement
         of the amendment, modification, supplement, restatement or discharge
         (or waiver) is sought.

                 e.   THIS AGREEMENT SHALL BE GOVERNED BY, AND CONSTRUED IN
         ACCORDANCE WITH THE LAWS OF THE STATE OF TEXAS, WITHOUT REGARD TO
         PRINCIPLES OF CONFLICTS OF LAWS, EXCEPT THAT, TO THE EXTENT THAT THE
         LAW OF A STATE IN WHICH A PORTION OF THE BOG PROPERTIES IS NOW OR
         HEREAFTER LOCATED (OR WHICH IS OTHER APPLICABLE TO A PORTION OF THE
         BOG PROPERTIES NECESSARILY GOVERNS, THE LAW OF SUCH STATE SHALL APPLY
         TO THAT PORTION OF THE BOG PROPERTIES LOCATED IN (OR OTHERWISE SUBJECT
         TO THE LAWS OF) SUCH STATE.

                 f.   This Agreement may be executed in counterparts, all of
         which are identical and all of which constitute one and the same
         instrument. It shall not be necessary for BOG and Gasco to sign the
         same counterpart and signature pages from different counterparts may
         be combined to form masters of this Agreement.

         This Agreement is executed by the parties hereto on the date set forth
beneath the signature of each but is effective for all purposes as of April 1,
1997.


         BRIGHAM OIL & GAS, L.P.            
         By:   Brigham, Inc.                 
         Its:  Managing General Partner     
                                            
                                            
                                            
         By: /s/ ANNE L. BRIGHAM                     
             ----------------------------------
               Name:  Anne L. Brigham       
               Title: Executive Vice President
               Date:  May 21, 1997             
                      -------------------------
                                            
                                            
                                            
         GASCO LIMITED PARTNERSHIP          
         By:   Gasco, Inc.                   
         Its:  General Partner              
                                            
                                            
                                            
         By: /s/ J. S. STEVENS, III                 
             -------------------------------
               Name:  J. S. Stevens, III    
               Title: President             
               Date:  5/22/97                  
                      -------------------------





                                      -17-
<PAGE>   18
                                  EXHIBIT LIST


EXHIBIT A:  Existing BOG Participation Agreements

EXHIBIT B:  AMI

EXHIBIT C:  Form of Assignment

EXHIBIT D:  Tax Partnership Agreement