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Exhibit 10.49

SECURITIES PURCHASE AGREEMENT

        This SECURITIES PURCHASE AGREEMENT (this "Agreement"), is entered into
as of December 20, 2002, between Brigham Exploration Company, a Delaware
corporation (the "Company"), and the Credit Suisse First Boston entities listed
on Schedule A hereto (collectively referred to as "Investors").

        WHEREAS, the Company has authorized the sale and issuance of an
aggregate of up to 500,000, shares of its Series B Preferred Stock (the
"Shares") and warrants to acquire 2,298,850 shares of its Common Stock, (the
"Warrants"), in the form attached hereto as Exhibit A;

        WHEREAS, Investors desire to purchase the Shares and the Warrants on the
terms and conditions set forth herein; and

        WHEREAS, the Company desires to issue and sell the Shares and the
Warrants to Investors on the terms and conditions set forth herein;

        NOW, THEREFORE, in consideration of the premises and the mutual
covenants and agreements herein contained, and intending to be legally bound
hereby, the Company and Investors hereby agree as follows:

ARTICLE I
TERMS OF THE TRANSACTION

        1.1    Authorization of Shares.    On or prior to the Closing (as
defined in Section 2.1 below), the Company shall have authorized (a) the sale
and issuance to Investors of the Shares and the Warrants and (b) the issuance of
such shares of Common Stock to be issued upon exercise of the Warrants (the
"Warrant Shares"). The Shares shall have the rights, preferences, privileges and
restrictions set forth in the Certificate of Designations of the Company, in the
form attached hereto as Exhibit B as amended by the Certificate of Amendment of
Certificate of Designations in the form attached hereto as Exhibit C (as so
amended, the "Certificate of Designations").

        1.2    Sale and Purchase.    Subject to the terms and conditions hereof,
at the Closing the Company hereby agrees to issue and sell to Investors, and
Investors agree to purchase from the Company, 500,000 Units at a purchase price
of Twenty Dollars ($20.00) per Unit, with each such Unit consisting of (i) one
Share and (ii) Warrants to purchase 4.5977 Warrant Shares and such Shares and
Warrants shall be allocated among the Investors as set forth on Schedule A
hereto.

ARTICLE II
CLOSING

        2.1    Closing.    The closing of the sale and purchase of the Shares
and Warrants under this Agreement (the "Closing") shall take place at the
offices of Brigham Exploration Company, 6300 Bridge Point Parkway, Building 2,
Suite 500, Austin, Texas 78730, at 10:00 a.m., local time, on the date of this
Agreement or at such other time or place as the Company and Investors may
mutually agree (the "Closing Date"). All closing transactions at the Closing
shall be deemed to have occurred simultaneously.

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ARTICLE III
REPRESENTATIONS AND WARRANTIES OF THE COMPANY

        The Company represents and warrants to Investors, as of the date hereof,
that:

        3.1    Corporate Organization.    The Company is a corporation duly
organized, validly existing, and in good standing under the laws of the State of
Delaware and has all requisite corporate power and authority in all material
respects to own, lease, and operate its properties and to carry on its business
as now being conducted. No actions or proceedings to dissolve the Company are
pending or, to the best knowledge of the Company, threatened. The Company is
duly qualified to do business as a foreign corporation and is in good standing
in each jurisdiction where such qualification is necessary, except where the
failure to so qualify or to be in good standing would not reasonably be expected
to have a Material Adverse Effect.

        3.2    Capitalization of the Company.    

        (a)  On the Closing Date, the authorized capital stock of the Company
will consist of 50,000,000 shares of Common Stock and 10,000,000 shares of
preferred stock, $.01 par value, 2,250,000 of which are designated as Series A
Preferred Stock and 1,000,000 of which are designated as Series B Preferred
Stock. As of the date hereof, (i) 16,302,857 shares of Common Stock are
outstanding and 1,730,238 shares of preferred stock are outstanding and
(ii) 1,852,235 shares of Common Stock are reserved for issuance upon exercise of
outstanding employee, officer and director stock options and 16,990,503 shares
of Common Stock are reserved for issuance upon exercise of outstanding warrants
or conversion rights. All outstanding shares of capital stock of the Company
have been validly issued and are fully paid and nonassessable, and no shares of
capital stock of the Company are subject to, nor have any been issued in
violation of, preemptive or similar rights. On the Closing Date, the rights,
preferences, privileges and restrictions of the Shares will be as stated in the
Certificate of Designations.

        (b)  Except as set forth above in subparagraph (a) of this Section 3.2,
there are outstanding (i) no shares of capital stock or other voting securities
of the Company; (ii) no securities of the Company convertible into or
exchangeable for shares of capital stock or other voting securities of the
Company; (iii) no options or other rights to acquire from the Company, and no
obligation of the Company to issue or sell, any shares of capital stock or other
voting securities of the Company or any securities of the Company convertible
into or exchangeable for such capital stock or voting securities; and (iv) no
equity equivalents, interests in the ownership or earnings, or other similar
rights of or with respect to the Company.

        (c)  Neither the execution of this Agreement nor the performance of the
Company's obligations hereunder, nor the consummation of any other transaction
currently contemplated by the Company or any of its Subsidiaries, will trigger
or cause any adjustment under any anti-dilution provisions or any other similar
provisions contained in any agreement as currently in effect that have the
effect of (i) causing a decrease in any exercise price or conversion price in
any security exercisable for or convertible into shares of Common Stock (a
"Common Stock Equivalent"), or (ii) causing an increase in the number of shares
of Common Stock that may be acquired upon conversion or exercise of a Common
Stock Equivalent.

        3.3    Authority Relative to This Agreement.    The Company has full
corporate power and authority to execute, deliver, and perform this Agreement
and to execute, deliver, and where applicable, perform the Ancillary Documents
to which it is a party and to consummate the transactions contemplated hereby
and thereby. The execution, delivery and performance by the Company of this
Agreement and the execution, delivery, and where applicable, performance by it
of the Ancillary Documents to which it is a party, and the consummation by it of
the transactions contemplated hereby and thereby, have been (or prior to the
Closing will have been) duly authorized by all necessary corporate action of the
Company. This Agreement has been duly executed and delivered by the Company and
constitutes, and

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each Ancillary Document executed or to be executed by the Company has been, or
when executed will be, duly executed and delivered by the Company and
constitutes, or when executed and delivered will constitute, a valid and legally
binding obligation of the Company, enforceable against the Company in accordance
with its terms, except that such enforceability may be limited by (i) applicable
bankruptcy, insolvency, reorganization, moratorium, and similar laws affecting
creditors' rights generally and (ii) general equitable principles (regardless of
whether such enforceability is considered in a proceeding in equity or at law).

        3.4    Noncontravention.    The execution, delivery, and performance by
the Company of this Agreement and the execution, delivery, and where applicable,
the performance by it of Ancillary Documents to which it is a party and the
consummation by it of the transactions contemplated hereby and thereby do not
and will not (i) conflict with or result in a violation of any provision of the
Company's Certificate of Incorporation, as amended, or the Company's Bylaws, as
amended, or the charter, bylaws, partnership agreement or other governing
instruments of any Subsidiary, (ii) conflict with or result in a violation of
any provision of, or constitute (with or without the giving of notice or the
passage of time or both) a default under, or give rise (with or without the
giving of notice or the passage of time or both) to any loss of material
benefit, or of any right of termination, cancellation, or acceleration under,
any Material Agreement, (iii) result in the creation or imposition of any
Encumbrance upon the properties of the Company or any Subsidiary or
(iv) assuming compliance with the matters referred to in Section 3.5, violate
any Applicable Law binding upon the Company or any Subsidiary, except, in the
case of clauses (ii), (iii) and (iv) above, for any such conflicts, violations,
defaults, terminations, cancellations, accelerations, or Encumbrances which
would not, individually or in the aggregate, have a Material Adverse Effect on
the Company.

        3.5    Consents and Approvals.    No consent, approval, order, or
authorization of, or declaration, filing, or registration with, any Governmental
Entity is required to be obtained or made by the Company or any Subsidiary in
connection with the execution, delivery, or performance by the Company of this
Agreement and the execution, delivery, and where applicable, performance of
Ancillary Documents to which it is a party or the consummation of the
transactions contemplated hereby and thereby, other than (i) compliance with any
applicable requirements of the Securities Act; (ii) compliance with any
applicable requirements of the Exchange Act; (iii) compliance with any
applicable state securities laws; (iv) filing of the Certificate of Amendment of
Certificate of Designations with the Delaware Secretary of State;.
(v) compliance with any applicable requirements of the HSR Act as a result of
the exercise of any of the Warrants; and (vi) such consents, approvals, orders,
or authorizations which, if not obtained, and such declarations, filings, or
registrations which, if not made, would not, individually or in the aggregate,
have a Material Adverse Effect on the Company. Except for such consents as are
obtained before or contemporaneously with consummation of the Closing, no
consent or approval of any person other than the Company, Investors or any
Governmental Entity is required to be obtained or made by the Company or any
Subsidiary in connection with the execution, delivery, or performance by the
Company of this Agreement and execution, delivery and, where applicable,
performance of the Ancillary Documents to which it is a party or the
consummation of the transactions contemplated hereby and thereby, other than
such consents, approvals, orders, or authorizations which, if not obtained, and
such declarations, filings, or registrations which, if not made, would not,
individually or in the aggregate, have a Material Adverse Effect on the Company.

        3.6    Authorization of Issuance; Reservation of Shares.    When issued
and delivered pursuant to this Agreement and the Certificate of Designations
against payment therefor, the Shares and the Warrants will be validly issued,
fully paid and nonassessable. The Warrant Shares have been duly and validly
reserved for issuance. The issuances of the Shares and the Warrants are not
subject to any preemptive or similar rights.

        3.7    Financial Condition.    The audited consolidated balance sheet of
the Company and its Subsidiaries as at December 31, 2001 and the related
consolidated statement of income, stockholders'

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equity and cash flow of the Company and its Subsidiaries for the fiscal year
ended on said date, with the opinion thereon of PricewaterhouseCoopers LLP
heretofore furnished to the Investors and the unaudited consolidated balance
sheet of the Company and its Subsidiaries as at September 30, 2002 and their
related consolidated statements of income, stockholders' equity and cash flow of
the Company and its Subsidiaries for the six-month period ended on such date
heretofore furnished to the Investors, are complete and correct and fairly
present the consolidated financial condition of the Company and its Subsidiaries
as at said dates and the results of its operations for the fiscal year and the
nine-month period on said dates, all in accordance with GAAP, as applied on a
consistent basis (subject, in the case of the interim financial statements, to
normal year-end adjustments). Neither the Company nor any Subsidiary has on the
Closing Date any debt, trade payables, contingent liabilities, liabilities for
taxes, unusual forward or long-term commitments or unrealized or anticipated
losses from any unfavorable commitments, except as referred to or reflected or
provided for in the Company's financial statements provided to the Investors as
set forth in this Section 3.7 or in Schedule 3.7 or except to the extent that
the existence of any of the foregoing would not have a Material Adverse Effect
relative to the Company. Since December 31, 2001, there has been no change or
event having a Material Adverse Effect relative to the Company, except as
disclosed to the Investors in writing. Since December 31, 2001, neither the
business nor the properties of the Company's Subsidiaries, taken as a whole,
have been materially and adversely affected as a result of any fire, explosion,
earthquake, flood, drought, windstorm, accident, strike or other labor
disturbance, embargo, requisition or taking of property or cancellation of
contracts, permits or concessions by any Governmental Entity, riot, activities
of armed forces or acts of God or of any public enemy.

        3.8    Litigation.    Except as disclosed in Schedule 3.8 hereto, at the
Closing Date there is no litigation, legal, administrative or arbitral
proceeding, investigation or other action of any nature pending or, to the best
of the Company's knowledge, threatened against or affecting the Company or any
Subsidiary which both (a) involves the possibility of any judgment or liability
against the Company or any Subsidiary not fully covered by insurance (except for
normal deductibles), and (b) would be more likely than not to have a Material
Adverse Effect relative to the Company.

        3.9    ERISA.    The Company and each ERISA Affiliate have complied in
all material respects with ERISA and, where applicable, the Code regarding each
Plan. Each Plan is, and has been, maintained in substantial compliance with
ERISA and, where applicable, the Code.

        No act, omission or transaction has occurred which could result in
imposition on the Company or any ERISA Affiliate (whether directly or
indirectly) of an amount of $100,000 or more as (i) either a civil penalty
assessed pursuant to section 502(c), (i) or (1) of ERISA or a tax imposed
pursuant to Chapter 43 of Subtitle D of the Code or (ii) breach of fiduciary
duty liability damages under section 409 of ERISA.

        No Plan (other than a defined contribution plan) or any trust created
under any such Plan has been terminated since September 2, 1974. No liability to
the Pension Benefit Guaranty Corporation in excess of $100,000 (other than for
the payment of current premiums which are not past due) by the Company or any
ERISA Affiliate has been or is expected by the Company or any ERISA Affiliate to
be incurred with respect to any Plan. No ERISA Event with respect to any Plan
has occurred which could reasonably be expected to result in liabilities of
$100,000 or more.

        Full payment when due has been made of all amounts which the Company or
any ERISA Affiliate is required under the terms of each Plan or applicable law
to have paid as contributions to such Plan, and no accumulated funding
deficiency in an amount of $100,000 or more (as defined in section 302 of ERISA
and section 412 of the Code), whether or not waived, exists with respect to any
Plan.

        The actuarial present value of the benefit liabilities under each Plan
which is subject to Title IV of ERISA does not, as of the end of the Company's
most recently ended fiscal year, exceed the current value of the assets
(computed on a plan termination basis in accordance with Title IV of ERISA) of

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such Plan allocable to such benefit liabilities by $100,000 or more. The term
"actuarial present value of the benefit liabilities" shall have the meaning
specified in section 4041 of ERISA.

        None of the Company or any ERISA Affiliate sponsors, maintains, or
contributes to an employee welfare benefit plan, as defined in section 3(1) of
ERISA, including, without limitation, any such plan maintained to provide
benefits to former employees of such entities, that may not be terminated by the
Company or any ERISA Affiliate in its sole discretion at any time without any
material liability.

        None of the Company or any ERISA Affiliate sponsors, maintains or
contributes to, or has at any time in the preceding six calendar years,
sponsored, maintained or contributed to, any Multiemployer Plan.

        None of the Company or any ERISA Affiliate is required to provide
security under section 401(a)(29) of the Code due to a Plan amendment that
results in an increase in current liability for the Plan.

        3.10    Taxes.    The Company has filed all United States Federal income
tax returns and all other tax returns which are required to be filed by it and
has paid all material taxes due pursuant to such returns or pursuant to any
assessment received by the Company, except for any taxes which are being
contested in good faith and by proper proceedings and against which adequate
reserves are being maintained. The charges, accruals and reserves on the books
of the Company in respect of taxes and other governmental charges are, in the
opinion of the Company, adequate. No tax lien has been filed and, to the
knowledge of the Company, no claim is being asserted with respect to any such
tax, fee or other charge, except for any taxes, fees or other charges which are
not material or which are being contested in good faith and by proper
proceedings and against which adequate reserves are being maintained.

        3.11    Titles, etc.    

        (a)  Subject to the matters set out in Schedule 3.11, each of the
Company and the Subsidiaries has defensible title, in all material respects, to
the material Oil and Gas Properties that are evaluated in the most recently
delivered reserve report, free and clear of all Liens, other than Excepted
Liens. Except for immaterial divergences, after giving full effect to the
Excepted Liens, the Company owns, in all material respects, the net interests in
production attributable to the Hydrocarbon Interests that are evaluated in the
most recently delivered reserve report, and the ownership of such Hydrocarbon
Interests shall not in any material respect obligate the Company to bear the
costs and expenses relating to the maintenance, development and operations of
each such Hydrocarbon Interest in an amount in excess of the working interest of
such Hydrocarbon Interest (without a corresponding increase in net revenue
interest). The Company does not believe, based upon information in its
possession, that its most recently delivered reserve report materially
overstates its oil and gas reserves, bearing in mind that reserves are evaluated
based upon estimates and assumptions with respect to which reasonable minds of
competent reserve engineers may differ.

        (b)  All leases and agreements necessary for the conduct of the business
of the Company and the Subsidiaries are valid and subsisting, in all material
respects, in full force and effect and there exists no default or event or
circumstance which with the giving of notice or the passage of time or both
would give rise to a default under any such lease or leases, which would have a
Material Adverse Effect on the conduct of the business of the Company and the
Subsidiaries.

        (c)  The Oil and Gas Properties presently owned (whether of record or
beneficially owned), leased or licensed by the Company and the Subsidiaries,
including, without limitation, all easements and rights of way, include all
properties necessary to permit the Company and the Subsidiaries to conduct their
business in all material respects in the same manner as its business has been
conducted prior to the Closing Date.

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        (d)  All of the properties of the Company and the Subsidiaries which are
reasonably necessary for the operation of their business are in good working
condition in all material respects and are maintained in accordance with prudent
business standards.

        3.12    No Material Misstatements.    Taken as a whole, the written
information, statements, exhibits, certificates, documents and reports furnished
to Investors by the Company or any Subsidiary in connection with the negotiation
of this Agreement do not contain any material misstatement of fact or omit to
state a material fact or any fact necessary to make the statements contained
therein not materially misleading in the light of the circumstances in which
made and with respect to the Company or any Subsidiary. As of the Closing Date,
there is no fact peculiar to the Company or Subsidiary which has a Material
Adverse Effect relative to the Company or in the future is reasonably likely to
have (so far as the Company can now foresee) a Material Adverse Effect and which
has not been set forth in this Agreement or the other documents, certificates
and statements furnished to Investors by or on behalf of the Company or any
Subsidiary prior to, or on, the Closing Date in connection with the transactions
contemplated hereby.

        3.13    Investment Company Act.    Neither the Company nor any
Subsidiary is an "investment company" or a company "controlled" by an
"investment company," within the meaning of the Investment Company Act of 1940,
as amended.

        3.14    Public Utility Holding Company Act.    Neither the Company nor
any Subsidiary is a "holding company," or a "subsidiary company" of a "holding
company," or an "affiliate" of a "holding company" or of a "subsidiary company"
of a "holding company," or a "public utility" within the meaning of the Public
Utility Holding Company Act of 1935, as amended.

        3.15    Subsidiaries.    Except as set forth on Schedule 3.15, the
Company has no Subsidiaries. Each Subsidiary is a corporation, limited liability
company or limited partnership, duly incorporated or organized, validly existing
and in good standing under the laws of its jurisdiction of incorporation or
organization, if applicable, and has all requisite corporate power and authority
in all material respects to own, lease, and operate its properties and to carry
on its business as now being conducted. Each Subsidiary is duly qualified to do
business as a foreign corporation or limited partnership, if applicable, and is
in good standing in each jurisdiction where such qualification is necessary,
except where the failure to so qualify or to be in good standing would not
reasonably be expected to have a Material Adverse Effect. There are outstanding
(i) no securities of any Subsidiary of the Company convertible into or
exchangeable for shares of capital stock or other voting securities of any
Subsidiary of the Company and (ii) no options or other rights to acquire from
any Subsidiary of the Company, and no obligation of any Subsidiary of the
Company to issue or sell, any shares of capital stock or other voting securities
of any Subsidiary of the Company or any securities of any Subsidiary of the
Company convertible into or exchangeable for such capital stock or voting
securities.

        3.16    Defaults.    Neither the Company nor any Subsidiary is in
default nor has any event or circumstance occurred which, but for the expiration
of any applicable grace period or the giving of notice, or both, would
constitute a default under any material agreement or instrument to which the
Company is a party or by which the Company is bound, which default would have a
Material Adverse Effect.

        3.17    Environmental Matters.    Except for matters which are more
likely than not to not have a Material Adverse Effect (or with respect to (c),
(d) and (e) below, where the failure to take such actions is more likely than
not to not have a Material Adverse Effect):

        (a)  To the best of the Company's knowledge, neither any Oil and Gas
Property of the Company or any of its Subsidiaries nor the operations conducted
thereon violate any order or requirement of any court or Governmental Entity or
any Environmental Laws;

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        (b)  Without limitation of clause (a) above, no Oil and Gas Property of
the Company or any of its Subsidiaries nor the operations currently conducted
thereon or, to the best knowledge of the Company, by any prior owner or operator
of such property or operation, are in violation of or subject to any existing,
pending or threatened action, suit, investigation, inquiry or proceeding by or
before any court or Governmental Entity or to any remedial obligations under
Environmental Laws;

        (c)  All notices, permits, licenses or similar authorizations, if any,
required to be obtained or filed by the Company or any of its Subsidiaries in
connection with the operation or use of any and all Oil and Gas Property of the
Company and each of its Subsidiaries, including without limitation present, or
to the best of Company's knowledge, past treatment, storage, disposal or release
of a hazardous substance or solid waste into the environment, have been duly
obtained or filed, and the Company and each Subsidiary thereof are in compliance
with the terms and conditions of all such notices, permits, licenses and similar
authorizations;

        (d)  To the best of the Company's knowledge, all hazardous substances,
solid waste, and oil and gas exploration and production wastes, if any,
generated at any and all Oil and Gas Property of the Company and each of its
Subsidiaries have in the past, during the tenure of ownership of the Company and
its Subsidiaries and prior thereto, been transported, treated and disposed of in
accordance with Environmental Laws and so as not to pose an imminent and
substantial endangerment to public health or welfare or the environment, and, to
the best knowledge of the Company, all such transport carriers and treatment and
disposal facilities have been and are operating in compliance with Environmental
Laws and so as not to pose an imminent and substantial endangerment to public
health or welfare or the environment, and are not the subject of any existing,
pending or threatened action, investigation or inquiry by any Governmental
Entity in connection with any Environmental Laws;

        (e)  To the best of the Company's knowledge, no hazardous substances,
solid waste, or oil and gas exploration and production wastes, have been
disposed of or otherwise released and there has been no threatened release of
any hazardous substances on or to any Oil and Gas Property of the Company or any
of its Subsidiaries except in compliance with Environmental Laws and so as not
to pose an imminent and substantial endangerment to public health or welfare or
the environment; and

        (f)    To the extent applicable, all Oil and Gas Property of the Company
and each of its Subsidiaries currently satisfies all design, operation, and
equipment requirements imposed by the OPA or scheduled as of the Closing Date to
be imposed by OPA during the term of this Agreement, and the Company does not
have any reason to believe that such Oil and Gas Property, to the extent subject
to OPA, will not be able to maintain compliance with the OPA requirements during
the term of this Agreement; and

        (g)  Neither the Company nor any of its Subsidiaries has any known
contingent liability in connection with any release or threatened release of any
oil, hazardous substance or solid waste into the environment.

        3.18    Compliance with the Law.    Neither the Company nor any
Subsidiary has violated any Governmental Requirement or failed to obtain any
license, permit, franchise or other governmental authorization necessary for the
ownership of any of its Oil and Gas Properties or the conduct of its business,
which violation or failure would have (in the event such violation or failure
were asserted by any Person through appropriate action) a Material Adverse
Effect. Except for such acts or failures to act as would not have a Material
Adverse Effect, the Oil and Gas Properties (and properties unitized therewith)
have been maintained and developed, and to the best of the Company's knowledge
operated, in a good and workmanlike manner and in conformity with all applicable
laws and all rules, regulations and orders of all duly constituted authorities
having jurisdiction and in conformity with the provisions of all leases,
subleases or other contracts comprising a part of the Hydrocarbon Interests and
other contracts and agreements forming a part of the Oil and Gas Properties;
specifically in this connection, but subject to the Material Adverse Effect
qualification set forth above, (i) after the Closing Date, no Oil and Gas
Property is subject to having allowable production reduced below the full

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and regular allowable (including the maximum permissible tolerance) because of
any overproduction (whether or not the same was permissible at the time) prior
to the Closing Date and (ii) none of the wells comprising a part of the Oil and
Gas Properties (or properties unitized therewith) are deviated from the vertical
more than the maximum permitted by applicable laws, regulations, rules and
orders, and such wells are, in fact, bottomed under and are producing from, and
the well bores are wholly within, the Oil and Gas Properties (or in the case of
wells located on properties unitized therewith, such unitized properties).

        3.19    Insurance.    Schedule 3.19 attached hereto contains an accurate
and complete description of all material policies of fire, liability, workmen's
compensation and other forms of insurance owned or held by the Company and each
Subsidiary as of the Closing Date. All such policies are in full force and
effect, all premiums with respect thereto covering all periods up to and
including the Closing Date have been paid, and no notice of cancellation or
termination has been received with respect to any such policy. Such policies are
sufficient for compliance with all requirements of law and of all agreements to
which the Company or any Subsidiary is a party; are valid, outstanding and
enforceable policies; provide adequate insurance coverage in at least such
amounts and against at least such risks (but including in any event public
liability) as are usually insured against in the same general area by companies
engaged in the same or a similar business for the assets and operations of the
Company and each Subsidiary; will remain in full force and effect through the
respective dates set forth in Schedule 3.19 with the payment of additional
premiums; and will not in any way be affected by, or terminate or lapse by
reason of, the transactions contemplated by this Agreement. Schedule 3.19
identifies all material risks, if any, which the Company, the Subsidiaries and
their respective Board of Directors or officers have designated as being self
insured. Neither the Company nor any Subsidiary has been refused any insurance
with respect to its assets or operations, nor has its coverage been limited
below usual and customary policy limits, by an insurance carrier to which it has
applied for any such insurance or with which it has carried insurance during the
last three years.

        3.20    Hedging Agreements.    Schedule 3.20 sets forth, as of the
Closing Date, a true and complete list of all Hedging Agreements (including
commodity price swap agreements, forward agreements or contracts of sale which
provide for prepayment for deferred shipment or delivery of oil, gas or other
commodities) of the Company and each Subsidiary.

        3.21    Material Agreements.    Set forth on Schedule 3.21 hereto is a
complete and correct list of all material agreements, leases, indentures,
purchase agreements, obligations in respect of letters of credit, guarantees,
joint venture agreements, and other instruments in effect or to be in effect as
of the Closing Date (other than Hedging Agreements) providing for, evidencing,
securing or otherwise relating to any material Debt of the Company or any
Subsidiary, and all obligations of the Company or any Subsidiary to issuers of
surety or appeal bonds (excluding operator's bonds, plugging and abandonment
bonds, and similar surety obligations obtained in the ordinary course of
business) issued for account of the Company or any such Subsidiary.

        3.22    Gas Imbalances.    As of the Closing Date, except as set forth
in the most recent Reserve Report furnished to Investors, on a net basis there
are no gas imbalances, take or pay or other prepayments with respect to the
Company's or any Subsidiary's Hydrocarbon Interests in the aggregate which would
require the Company or such Subsidiary to deliver five percent (5%) or more of
the monthly production from the Company's and its Subsidiaries' Hydrocarbons
produced on a monthly basis from the Hydrocarbon Interests, at some future time
without then or thereafter receiving full payment therefor.

        3.23    Brokerage Fees.    The Company has not retained any financial
advisor, broker, agent, or finder or paid or agreed to pay any financial
advisor, broker, agent, or finder on account of the sale by the Company and the
purchase by Investors of the Shares pursuant to this Agreement.

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        3.24    SEC Filings.    The Company has complied in all material
respects with its obligations to file with the Securities and Exchange
Commission all forms, reports, schedules, statements and other documents
required to be filed by it since January 1, 1999 under the Securities Act and
the Exchange Act. All forms, reports, schedules, statements, and other documents
(including all amendments thereto) filed by the Company with the Securities and
Exchange Commission since such date are herein collectively referred to as the
"SEC Filings". The SEC Filings, at the time filed, complied in all material
respects with all applicable requirements of federal securities laws. None of
the SEC Filings, including, without limitation, any financial statements or
schedules included therein, at the time filed or as same may have been amended,
contained any untrue statement of a material fact or omitted to state any
material fact required to be stated therein or necessary in order to make the
statements contained therein, in light of the circumstances under which they
were made, not misleading.

        3.25    Stockholder Approval.    Neither the execution of this Agreement
nor the consummation of the transactions contemplated hereunder require the
approval of the stockholders of the Company under the applicable listing rules
of the Nasdaq Stock Market, Inc.; provided, however, that certain of the
anti-dilution provisions contained in the Warrants shall not be enforceable
until after approval of the stockholders of the Company as set forth therein.

ARTICLE IV
REPRESENTATIONS AND WARRANTIES OF INVESTORS

        Each Investor represents and warrants to the Company that:

        4.1    Organization.    Each of DLJ Merchant Banking Partners III, LP
("MBP"); Millennium Partners II, L.P. ("MPII"); and MBP III Plan Investors, L.P.
("MPIII") is a limited partnership duly organized, validly existing and in good
standing under the laws of the State of Delaware. Each of DLJ Merchant Banking
III, Inc., as Advisory General Partner on behalf of DLJ Offshore Partners III,
C.V.("DOP"); DLJ Merchant Banking III, Inc., as Advisory General Partner on
behalf of DLJ Offshore Partners III-1, C.V. and as attorney-in-fact for DLJ
Merchant Banking III, L.P., as Associate General Partner of DLJ Offshore
Partners III-1, C.V. ("DOP-1"); and DLJ Merchant Banking III, Inc., as Advisory
General Partner on behalf of DLJ Offshore Partners III-2, C.V. and as
attorney-in-fact for DLJ Merchant Banking III, L.P., as Associate General
Partner of DLJ Offshore Partners III-2, C.V. ("DOP-2") is a limited partnership
(commanditaire vennootschap) duly organized, validly existing and in good
standing under the laws of the Netherlands Antilles. DLJ MB PartnersIII GmbH &
Co. KG ("MBP GmbH") is a limited partnership duly organized, validly existing
and in good standing under the laws of the Republic of Germany. Each Investor
has all requisite corporate power and authority in all material respects to own,
lease, and operate its properties and to carry on its business as now being
conducted. No actions or proceedings to dissolve either Investor are pending or,
to the best knowledge of any Investor, threatened.

        4.2    Authority Relative to This Agreement.    Each Investor has full
corporate or (if applicable) other power and authority to execute, deliver, and
perform this Agreement and execute, deliver and, where applicable, perform the
Ancillary Documents to which it is a party and to consummate the transactions
contemplated hereby and thereby. The execution, delivery, and performance by
each Investor of this Agreement and execution, delivery, and, where applicable,
performance of the Ancillary Documents to which it is a party, and the
consummation by it of the transactions contemplated hereby and thereby, have
been duly authorized by all necessary corporate (if applicable) action of such
Investor. This Agreement has been duly executed and delivered by each Investor
and constitutes, and each Ancillary Document executed or to be executed by each
Investor has been, or when executed will be, duly executed and delivered by such
Investor and constitutes, or when executed and delivered will constitute, a
valid and legally binding obligation of such Investor, enforceable against such
Investor in accordance with its terms, except that such enforceability may be
limited by (i) applicable bankruptcy, insolvency, reorganization, moratorium,
and similar laws affecting creditors' rights generally and (ii) general

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equitable principles (regardless of whether such enforceability is considered in
a proceeding in equity or at law).

        4.3    Noncontravention.    The execution, delivery, and performance by
each Investor of this Agreement and the execution, delivery and, where
applicable, performance of Ancillary Documents to which it is a party and the
consummation by it of the transactions contemplated hereby and thereby do not
and will not (i) conflict with or result in a violation of any provision of
MBP's, MPII's or MPIII's Certificate of Limited Partnership or partnership
agreement, DOP's, DOP-1's or DOP-2's Agreement of Limited Partnership, or MBP
GmbH's Certificate of Kommanditgesellschaft/L.P., (ii) conflict with or result
in a violation of any provision of, or constitute (with or without the giving of
notice or the passage of time or both) a default under, or give rise (with or
without the giving of notice or the passage of time or both) to any right of
termination, cancellation, or acceleration under, any bond, debenture, note,
mortgage, indenture, lease, agreement or other instrument or obligation to which
any Investor is a party or by which Investor or any of its properties may be
bound, (iii) result in the creation or imposition of any Encumbrance upon the
properties of any Investor, or (iv) violate any Applicable Law binding upon any
Investor, except, in the case of clauses (ii), (iii) and (iv) above, for any
such conflicts, violations, defaults, terminations, cancellations,
accelerations, or Encumbrances which would not, individually or in the
aggregate, have a Material Adverse Effect on any Investor.

        4.4    Consents and Approvals.    No consent, approval, order, or
authorization of, or declaration, filing, or registration with, any Governmental
Entity is required to be obtained or made by Investors in connection with the
execution, delivery, or performance by Investors of this Agreement and the
execution, delivery and, where applicable, performance of the Ancillary
Documents to which it is a party or the consummation of the transactions
contemplated hereby or thereby. No consent or approval of any person other than
any Governmental Entity is required to be obtained or made by any Investor in
connection with the execution, delivery or performance by Investors of this
Agreement and the execution, delivery and, where applicable, performance of the
Ancillary Documents to which it is a party or the consummation of the
transactions contemplated hereby or thereby.

        4.5    Purchase for Investment.    Each Investor understands that none
of the Shares, the Warrants or the Warrant Shares have been registered under the
Securities Act. Each Investor also understands that the Shares, the Warrants and
the Warrant Shares are being offered and sold pursuant to an exemption from
registration contained in the Securities Act based in part upon Investors'
representations contained in this Agreement. Each Investor hereby represents and
warrants as follows:

        (a)    Investor Bears Economic Risk.    Each Investor has substantial
experience in evaluating and investing in private placement transactions of
securities in companies similar to the Company so that it is capable of
evaluating the merits and risks of its investment in the Company and has the
capacity to protect its own interests. Without limiting the generality of the
foregoing, each Investor further represents that it has such knowledge regarding
the oil and gas industry and the business of the Company and the current
circumstances surrounding such industry and business that it is capable of
evaluating the merits and risks of the acquisition of the Shares, the Warrants
and the Warrant Shares. Each Investor must bear the economic risk of this
investment indefinitely unless the Shares, the Warrants or the Warrant Shares
are registered pursuant to the Securities Act, or an exemption from registration
is available. Each Investor understands that the Company has no present
intention of registering the Shares, the Warrants or the Warrant Shares. Each
Investor also understands that there is no assurance that any exemption from
registration under the Securities Act will be available and that, even if
available, such exemption may not allow an Investor to transfer all or any
portion of the Shares, Warrants or Warrant Shares under the circumstances, in
the amounts or at the times an Investor might propose.

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        (b)    Acquisition for Own Account.    Each Investor is acquiring the
Shares, the Warrants and Warrant Shares for such Investor's own account for
investment only, and not with a view towards their distribution.

        (c)    Investor Can Protect Its Interest.    Each Investor represents
that by reason of its, or of its management's, business or financial experience,
such Investor has the capacity to protect its own interests in connection with
the transactions contemplated in this Agreement and the Ancillary Agreements.
Further, no Investor is aware of any publication of any advertisement in
connection with the transactions contemplated in the Agreement.

        (d)    Accredited Investor.    Each Investor represents that it is an
accredited investor within the meaning of Regulation D under the Securities Act.

        (e)    Company Information.    Each Investor has had access to the
Company's SEC Filings and has had an opportunity to discuss the Company's
business, management and financial affairs with directors, officers and
management of the Company and has had the opportunity to review the Company's
operations and facilities. Each Investor has also had the opportunity to ask
questions of, and receive answers from, the Company and its management regarding
the terms and conditions of this investment. Each Investor hereby acknowledges
and affirms that it has completed its own independent investigation, analysis,
and evaluation of the Company and its subsidiaries, that it has made all such
reviews and inspections of the business, assets, results of operations,
condition (financial or otherwise), and prospects of the Company and its
subsidiaries as it has deemed necessary or appropriate, and that in making its
decision to enter into this Agreement and to consummate the transactions
contemplated hereby it has relied solely on its own independent investigation,
analysis, and evaluation of the Company and its subsidiaries, or that of its own
independent advisers in evaluating its investment in the Shares, Warrants and
Warrant Shares.

        (f)    Rule 144.    Each Investor acknowledges and agrees that the
Shares and the Warrants, and, if issued, the Warrant Shares, must be held
indefinitely unless they are subsequently registered under the Securities Act or
an exemption from such registration is available. Each Investor has been advised
or is aware of the provisions of Rule 144, which permits limited resale of
shares purchased in a private placement subject to the satisfaction of certain
conditions, including, among other things: the availability of certain current
public information about the Company, the resale occurring following the
required holding period under Rule 144 and the number of shares being sold
during any three-month period not exceeding specified limitations.

        (g)    Transfer Restrictions.    Each Investor acknowledges and agrees
that the Shares, the Warrants and the Warrant Shares are subject to restrictions
on transfer as set forth in Section 5.5, below, and further understands that the
Shares, the Warrants and the Warrant Shares will not have been registered
pursuant to the Securities Act or any applicable state securities laws, that the
Shares, the Warrants and the Warrant Shares will be characterized as "restricted
securities" under federal securities laws, and that under such laws and
applicable regulations the Shares, the Warrants and the Warrant Shares cannot be
sold or otherwise disposed of without registration under the Securities Act or
an exemption therefrom. In this connection, each Investor represents that it is
familiar with Rule 144 promulgated under the Securities Act, as currently in
effect, and understands the resale limitations imposed thereby and by the
Securities Act. Appropriate stop transfer instructions may be issued to the
transfer agent for securities of the Company (or a notation may be made in the
appropriate records of the Company) in connection with the Shares, the Warrants
or the Warrant Shares.

        (h)    Confirmation.    The acquisition of the Shares by an Investor at
the Closing shall constitute such Investor's confirmation of the foregoing
representations.

        4.6    No Other Shares.    Except for such rights as may be conferred on
an Investor under the First Purchase Agreement, the Second Purchase Agreement or
by this Agreement and the Ancillary

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Documents, Investors do not beneficially own, directly or indirectly, any shares
of capital stock or other securities of the Company or any of its Subsidiaries.

        4.7    Financial Resources.    Each Investor has the financial resources
available to it as are necessary to perform its obligations to acquire the
Shares pursuant to the terms of this Agreement.

        4.8    Brokerage Fees.    No Investor has retained any financial
advisor, broker, agent, or finder or paid or agreed to pay any financial
advisor, broker, agent, or finder on account of the sale by the Company and the
purchase by Investors of the Shares pursuant to this Agreement.

ARTICLE V
ADDITIONAL AGREEMENTS

        5.1    Reasonable Best Efforts.    

        (a)  Each party hereto agrees that it will use its reasonable best
efforts to take, or cause to be taken, all action and to do, or cause to be
done, all things reasonably necessary, proper, or advisable under Applicable
Laws to consummate the transactions contemplated by this Agreement, including,
without limitation, (i) cooperation in determining whether any consents,
approvals, orders, authorizations, waivers, declarations, filings, or
registrations of or with any Governmental Entity or third party are required in
connection with the consummation of the transactions contemplated hereby;
(ii) reasonable best efforts to obtain any such consents, approvals, orders,
authorizations, and waivers and to effect any such declarations, filings, and
registrations; (iii) reasonable best efforts to cause to be lifted or rescinded
any injunction or restraining order or other order adversely affecting the
ability of the parties to consummate the transactions contemplated hereby;
(iv) reasonable best efforts to defend, and cooperation in defending, all
lawsuits or other legal proceedings challenging this Agreement or the
consummation of the transactions contemplated hereby; and (v) the execution of
any additional instruments necessary to consummate the transactions contemplated
hereby.

        (b)  Without limiting the generality of Section 5.1(a), to the extent
required by the HSR Act, each of the parties hereto shall (i) file or cause to
be filed, as promptly as practicable but in no event later than five
(5) consecutive Business Days after the execution and delivery of this
Agreement, with the Federal Trade Commission and the United States Department of
Justice, all reports and other documents required to be filed by such party
under the HSR Act concerning the transactions contemplated hereby and
(ii) promptly comply with or cause to be complied with any requests by the
Federal Trade Commission or the United States Department of Justice for
additional information concerning such transactions, in each case so that the
waiting period applicable to this Agreement and the transactions contemplated
hereby under the HSR Act shall expire as soon as practicable after the execution
and delivery of this Agreement. Each party hereto agrees to request, and to
cooperate with the other party or parties in requesting, early termination of
any applicable waiting period under the HSR Act. Notwithstanding the foregoing,
if any report or other document is required to be filed by any Investor under
the HSR Act solely as a result of the purchase and sale of the Shares or the
Warrants (with no regard to any other securities held by such Investor or its
Affiliates), the Company shall pay any and all fees and expenses, including
filing fees and legal expenses, incurred by such Investor in connection with the
filing of such reports or other documents and any other actions required to
comply with the provisions of the HSR Act.

        5.2    Press Releases.    Except as may be required by Applicable Law or
by the rules of any national securities exchange or registered securities
association, prior to the Closing, neither Investors nor the Company shall issue
any press release with respect to this Agreement or the transactions
contemplated hereby without the prior consent of the other party (which consent
shall not be unreasonably withheld under the circumstances). Any such press
release required by Applicable Law or by the rules of any national securities
exchange or registered securities association shall only be made after
reasonable notice to the other party.

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        5.3    Fees and Expenses.    Except as otherwise expressly provided in
this Agreement, all fees and expenses, including fees and expenses of counsel,
financial advisors and accountants, incurred in connection with this Agreement
and the transactions contemplated hereby shall be paid by the party incurring
such fee or expense.

        5.4    Survival.    The representations and warranties made herein shall
survive the Closing, regardless of any investigation made by or on behalf of any
party, until the second anniversary of the Closing Date; provided, however, the
representations and warranties contained in Sections 3.9, 3.10 and 3.17 shall
survive until the expiration of the applicable statute limitations relating to
the subject matters of such representations and warranties (the "Survival
Date".) All statements as to factual matters contained in any certificate or
other instrument delivered by or on behalf of the Company pursuant hereto in
connection with the transactions contemplated hereby shall be deemed to be
representations and warranties by the Company herein for purposes of this
Section 5.4. No action may be brought with respect to a breach of any
representation or warranty after the Survival Date unless, prior to such time,
the party seeking to bring such an action has notified the other parties of such
claim, specifying in reasonable detail the nature of the loss suffered.

        5.5    Transfer Restrictions.    

        (a)  Notwithstanding any provision contained in this Agreement to the
contrary, each Investor agrees that it will not, directly or indirectly, sell,
assign, transfer, pledge, encumber, or otherwise dispose of any of the Shares,
Warrants or Warrant Shares except:

(i)In compliance with Rule 144; provided, however, that the Investor shall
provide the Company with copies of all filings made with the Securities and
Exchange Commission with respect to sales of securities under Rule 144 and with
such other information and documents as the Company shall reasonably require in
order to assure full compliance with Rule 144; or (ii) Pursuant to a no-action
letter or other interpretive statement or release of the Securities and Exchange
Commission to the effect that the proposed sale or other disposition may be
effected without registration under the Securities Act; or

(iii)Pursuant to an applicable exemption (other than Rule 144) under the
Securities Act; provided, however, that the Investor shall have furnished the
Company with an opinion of counsel, which opinion and counsel shall be
reasonably acceptable to the Company, to the effect that such disposition does
not require registration of such securities under the Securities Act; provided
further, however, that no opinion of counsel shall be required in the case of a
transfer to affiliates (as hereinafter defined) of Investor if such affiliates
shall have furnished the Company with the representations contained in
Section 4.5 of this Agreement and shall have agreed with the Company to be
subject to the terms of this Agreement to the same extent as if an original
holder of securities pursuant hereto. For purposes of this Section 5.5(a)(iii),
"affiliates" shall mean one or more of (A) Affiliates as defined in
Section 11.1, or (B) any other Investor; or

(iv)Pursuant to an effective registration statement filed under the Securities
Act.

        (b)  It is agreed and understood by each Investor that the certificates
or instruments representing the Shares, Warrants and Warrant Shares shall each
be stamped or otherwise imprinted with a legend in substantially the following
form:

        "THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED
UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR ANY APPLICABLE STATE SECURITIES
LAWS, AND MAY NOT BE SOLD OR TRANSFERRED IN THE ABSENCE OF SUCH REGISTRATION OR
AN EXEMPTION THEREFROM. SUCH SECURITIES ARE SUBJECT TO THE RESTRICTIONS AND
PRIVILEGES SPECIFIED IN A SECURITIES PURCHASE AGREEMENT, DATED AS OF DECEMBER
20, 2002, BETWEEN BRIGHAM EXPLORATION COMPANY AND THE

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INITIAL HOLDERS OF SECURITIES NAMED THEREIN, A COPY OF WHICH IS ON FILE WITH THE
SECRETARY OF BRIGHAM EXPLORATION COMPANY AND WILL BE FURNISHED WITHOUT CHARGE TO
THE HOLDER HEREOF UPON WRITTEN REQUEST, AND THE HOLDER OF THIS CERTIFICATE
AGREES TO BE BOUND THEREBY."

        5.6    Consideration.    The sum of Five Hundred Thousand Dollars
($500,000) shall be deducted from the Purchase Price as consideration for the
Investors entering into the purchase of the Units. The Company shall pay all
reasonable out-of-pocket expenses ("Investor Expenses") incurred by the
Investors, including attorneys' fees. At the Closing, the company shall pay
$75,000 in partial payment of the Investor Expenses, with a detailed final
accounting for the Investor Expenses to be submitted by the Investors within
thirty (30) days after the Closing Date. The Company shall pay to the Investors
such final amount of Investor Expenses (less expenses already paid at Closing)
within thirty (30) days following the Company's receipt of such final accounting
from the Investors.

        5.7    Action at Annual Meeting of Stockholders.    

        (a)  The Company shall take all action necessary in accordance with
applicable law and the Company's Certificate of Incorporation and Bylaws to have
the Company's common stockholders, at the Annual Meeting to be held on or before
May 31, 2003, consider and approve the matters described in the Stockholders
Voting Agreement dated December 20, 2002, by and among the Company and certain
of its stockholders, such approval, when so obtained, shall be referred to as
the "Stockholder Approval". The Company shall not mail or otherwise distribute
the proxy statement or information statement (or any related proxy materials or
amendments or supplements thereto, if any) relating to the Annual Meeting to its
stockholders without consultation with Investors and their counsel, and such
proxy statement or information statement and such other items shall, to the
extent same relate to the subject matter of the Stockholders Voting Agreement,
be in such form as Investors and their counsel shall approve (such approval not
to unreasonably withheld).

        (b)  The Company shall provide a certificate signed by a duly authorized
officer of the Company to each holder of Warrants promptly after the Annual
Meeting certifying whether the Stockholder Approval has been obtained at the
Annual Meeting and whether the anti-dilution provisions contained in the
Warrants are then enforceable.

        5.8    Capitalization Certificate.    The Company shall provide,
immediately after the Closing, a schedule reflecting the capitalization of the
Company as of immediately after the transactions contemplated by this Agreement,
including at least the information provided in the representation in Section 3.2
and indicating the number of fully-diluted shares of Common Stock, and certified
by the Chief Financial Officer of the Company (the "Certificate"). Until the
second anniversary of the Closing Date, the Company shall amend the Certificate
at any time after the Closing to reflect any changes to the Certificate (which
in all cases shall reflect the capitalization of the Company as of immediately
after the transactions contemplated by this Agreement) if the Company learns
that the Certificate is incorrect or not complete in any respect.
Notwithstanding any provision contained in this Agreement, the Amended
Registration Rights Agreement and the Warrant Certificate, if the number of
fully-diluted shares of common stock as reflected in the Certificate at any time
is more than 33,828 shares in excess of 33,827,779 shares of Common Stock, then
the number of shares purchasable upon exercise of the Warrant shall be increased
to a number of shares equal to 6.796% of the fully-diluted shares of Common
Stock. Upon any such adjustment to the number of shares to be acquired upon
exercise of the Warrant, the holder of the Warrant shall deliver to the Company
the Warrant Certificate for cancellation and immediately thereupon the Company
shall issue a new Warrant Certificate reflecting the registered number of shares
purchasable thereunder. For purposes of this Section 5.8, the term
"fully-diluted shares of Common Stock" means the sum of shares of Common Stock
outstanding, plus all shares of Common Stock issuable pursuant to (i) the
conversion or exchange of securities that are convertible into or exchangeable
for shares of Common Stock or the exercise of any option, warrant or other right
to acquire shares of Common Stock from the Company, (ii) the conversion or
exchange of

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any security that is convertible into or exchangeable for any securities
referred to in Section 5.8(i) or the exercise of any security that is
exercisable for any securities referenced in Section 5.8(i), and (iii) the
exercise of any rights under any agreement regarding equity equivalents,
interest in the ownership or earnings, or other similar rights of or with
respect to the Company.

        5.9    Restrictions on Certain Actions.    Investors hereby agree
(subject to the occurrence of the Closing) that for a period of one year from
the Closing Date, Investors shall not, without the prior written approval of the
Board of Directors of the Company, in any manner, directly or indirectly,
acquire for their own accounts any Voting Securities (or beneficial ownership
thereof), except by way of stock dividends or other distributions or offerings
made available to holders of Voting Securities generally and except for
acquisitions of Common Stock upon exercise of the Warrants (as defined herein),
upon exercise of the Warrants (as defined in the First Purchase Agreement), upon
exercise of the Warrants (as defined in the Second Purchase Agreement) or upon
conversion of the Loans (as defined in the Assignment Agreement) in accordance
with the Equity Conversion Agreement (as defined in the Assignment Agreement).
The parties acknowledge that various Affiliates of the Investors are brokers or
investment advisors or are otherwise engaged in transactions in securities
generally as part of their ordinary course of business. The parties agree that
actions taken by Affiliates of the Investors as such in the ordinary course of
their business, such as acting as broker for clients acquiring shares of Voting
Securities, shall not be deemed a violation of any of the provisions of this
Section 5.9.

ARTICLE VI
CONDITIONS TO OBLIGATIONS OF THE COMPANY

        The obligations of the Company to consummate the transactions
contemplated by this Agreement shall be subject to the fulfillment on or prior
to the Closing Date of each of the following conditions:

        6.1    Representations and Warranties.    All the representations and
warranties of Investors contained in this Agreement shall be true and correct in
all material respects, except as affected by transactions contemplated or
permitted by this Agreement.

        6.2    Covenants and Agreements.    Investors shall have performed and
complied with in all material respects all covenants and agreements required by
this Agreement to be performed or complied with by them on or prior to the
Closing Date.

        6.3    HSR Act.    All waiting periods (and any extensions thereof)
applicable to this Agreement and the transactions contemplated hereby under the
HSR Act shall have expired or been terminated.

        6.4    Legal Proceedings.    No Proceeding shall, on the Closing Date,
be pending or threatened seeking to restrain, prohibit or obtain damages or
other relief in connection with this Agreement or the consummation of the
transactions contemplated hereby.

        6.5    Consents.    All consents, approvals, orders, authorizations and
waivers of, and all declarations, filings and registrations with, third parties
(including Governmental Entities) required to be obtained or made by or on the
part of the parties hereto, or otherwise reasonably necessary for the
consummation of the transactions contemplated hereby, shall have been obtained
or made, and all thereof shall be in full force and effect at the time of
Closing.

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ARTICLE VII
CONDITIONS TO OBLIGATIONS OF INVESTORS

        The obligations of Investors to consummate the transactions contemplated
by this Agreement shall be subject to the fulfillment on or prior to the Closing
Date of each of the following conditions:

        7.1    Representations and Warranties.    All the representations and
warranties of the Company contained in this Agreement shall be true and correct
in all material respects, except as affected by transactions contemplated or
permitted by this Agreement (or the announcement thereof).

        7.2    Covenants and Agreements.    The Company shall have performed and
complied with in all material respects all covenants and agreements required by
this Agreement to be performed or complied with by it on or prior to the Closing
Date.

        7.3    HSR Act.    All waiting periods (and any extensions thereof)
applicable to this Agreement and the transactions contemplated hereby under the
HSR Act shall have expired or been terminated.

        7.4    Legal Proceedings.    No Proceeding shall, on the Closing Date,
be pending or threatened seeking to restrain, prohibit or obtain damages or
other relief in connection with this Agreement or the consummation of the
transactions contemplated hereby.

        7.5    Consents.    All consents, approvals, orders, authorizations and
waivers of, and all declarations, filings and registrations with, third parties
(including Governmental Entities) required to be obtained or made by or on the
part of the parties hereto, or otherwise reasonably necessary for the
consummation of the transactions contemplated hereby, shall have been obtained
or made, and all thereof shall be in full force and effect at the time of
Closing.

        7.6    Legal Opinion.    Thompson & Knight, L.L.P., counsel to the
Company, shall have delivered to the Investors a legal opinion satisfactory in
form and substance to the Investors.

        7.7.    Assignment Agreement.    All conditions precedent to the
effectiveness of the sale, assignment and transfer contemplated under the
Assignment Agreement shall have been satisfied or waived.

        7.8    Letter Agreement.    All conditions precedent to the purchase of
the Shares and Warrants contained in the Letter Agreement dated as of
November 21, 2002, between the Company, BOG, and DLJ Merchant Banking III, Inc.,
shall have been satisfied or waived.

ARTICLE VIII
COVENANTS

        8.1    Affirmative Covenants.    The Company covenants and agrees that,
so long as any of the Shares are outstanding:

        (a)  Financial Statements and Other Reports. The Company shall deliver,
or shall cause to be delivered, to the Investors:

(i)Annual Financial Statements. As soon as available and in any event within
90 days after the end of each fiscal year of the Company and its consolidated
Subsidiaries for such fiscal year, and the related consolidated and unaudited
consolidating balance sheets of the Company and its consolidated Subsidiaries as
at the end of such fiscal year, and setting forth in each case in comparative
form the corresponding figures for the preceding fiscal year, and accompanied by
the related opinion of independent public accountants which opinion shall state
that said financial statements fairly present the consolidated financial
condition and results of operations of the Company and its consolidated
Subsidiaries as at the end of, and for, such fiscal year and that such financial
statements have been prepared in accordance with GAAP except for such changes in
such principles with which the independent public accountants shall have
concurred.

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(ii)Quarterly Financial Statements. As soon as available and in any event within
60 days after the end of each of the first three fiscal quarterly periods of
each fiscal year of the Company, consolidated statements of income,
stockholders' equity, changes in financial position and cash flow of the Company
and its consolidated Subsidiaries for such period and for the period from the
beginning of the respective fiscal year to the end of such period, and the
related consolidated and consolidating balance sheets as at the end of such
period.

(iii)Monthly Financial Statements. As soon as available and in any event within
forty-five (45) days after the end of each calendar month that is not also the
end of one of the Company's first three fiscal quarterly periods or of the
Company's fiscal year, consolidated statements of income and changes in
financial position of the Company and its consolidated Subsidiaries for such
period and for the period from the beginning of the respective fiscal year to
the end of such period, and the related consolidated balance sheets as at the
end of such period and beginning statements setting forth in each case in
comparative form the corresponding figures for the corresponding period in the
preceding fiscal year.]

        (b)  SEC Filings, Etc. Promptly, upon its becoming available, each
financial statement, report, notice or proxy statement sent by the Company to
stockholders generally.

        (c)  Engineering Reports. Not later than April 30 and October 30 of each
year, the Company shall furnish to the Investors a Reserve Report as of the
preceding December 31 and June 30, respectively. The Reserve Report to be
furnished in April of each year shall be prepared by certified independent
petroleum engineers or other independent petroleum consultant(s) and the Reserve
Report to be furnished in October of each year shall be prepared by or under the
supervision of the chief engineer or Vice President of Operations of the Company
who shall certify such Reserve Report to have been prepared in accordance with
the procedures used in the immediately preceding April Reserve Report. At
Company's option, the Reserve Report to be furnished in October of each year may
instead consist of a report from the independent petroleum engineers referred to
above on any new wells and a roll-forward by Company on any wells previously
reported in the Reserve Report described in the immediately preceding April.

        (d)  Exchange Act Reports. At all times (i) timely file all reports
required to be filed by the Company under Section 13(d) or Section 15 of the
Exchange Act and the rules and regulations thereunder, and (ii) if the Company
is no longer subject to the requirements of the Exchange Act, provide holders of
the Shares reports in substantially the same form and at the same times as would
be required if the Company were subject to the Exchange Act.

        (e)  Nasdaq Listing. Maintain at all times a valid listing for the
Common Stock on a national securities exchange or the National Market System or
SmallCap Market of the NASDAQ Stock Market, Inc.

        (f)    Further Assurances. The Company at its expense will promptly
execute and deliver to the Investors upon request all such other documents,
agreements and instruments to comply with or accomplish the covenants and
agreements of the Company in this Agreement or any other agreements and
documents executed by and between the Company and the Investors.

        8.2    Negative Covenants.    The Company covenants and agrees that, so
long as at least 10% of the Shares are outstanding, without the prior written
consent of the persons holding 75% of the then outstanding Shares:

        (a)  Dividends, Distributions and Redemptions. The Company will not
declare or pay any dividend, purchase, redeem, or otherwise acquire for value
any, other than those issued under the First Purchase Agreement or the Second
Purchase Agreement, Parity Security or Junior Security

17

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now or hereafter outstanding, return any capital or make a distribution of its
assets to its stockholders.

        (b)  Nature of Business. Neither the Company nor Brigham Oil & Gas, L.P.
will allow any material change to be made in the character of its business as an
independent oil and gas exploration and production company.

        (c)  Environmental Matters. Neither the Company nor any Subsidiary will
knowingly cause or permit any of its Property to be in violation of, or
knowingly do anything or permit anything to be done which will subject any such
Property to any remedial obligations under any Environmental Laws, assuming
disclosure to the applicable Governmental Authority of all relevant facts,
conditions and circumstances, if any, pertaining to such Property where such
violations or remedial obligations would have a Material Adverse Effect.

        (d)  Transactions with Affiliates. Neither the Company nor any
Subsidiary will enter into any transaction, including, without limitation, any
purchase, sale, lease or exchange of Property or the rendering of any service,
with any Affiliate unless such transactions are otherwise not in violation of
this Agreement, and are upon fair and reasonable terms no less favorable to it
than it would obtain in a comparable arm's length transaction with a Person not
an Affiliate.

        8.3    Venture Capital Investment.    The rights contained in this
Section 8 are intended to satisfy the requirement of management rights for
purposes of qualifying the ownership of Common Stock, Preferred Stock and
Warrants by one or more of the Investors as a venture capital investment for
purposes of the Department of Labor "plan asset" regulation, 29 C.F.R. §
2510.3-101. In the event such rights are not satisfactory for such purpose, the
Company and such Investors shall reasonably cooperate in good faith to agree
upon mutually satisfactory management rights that satisfy such regulation.

        8.4    Amended Registration Rights Agreement.    Within two business
days after the Closing, the Company shall execute and deliver to the Investors
the Second Amendment to Registration Rights Agreement by and among the Company,
the Investors, MB and ESC.

ARTICLE IX
AMENDMENT AND WAIVER

        9.1    Amendment.    This Agreement may not be amended except by an
instrument in writing signed by or on behalf of all the parties hereto.

        9.2    Waiver.    No failure or delay by a party hereto in exercising
any right, power, or privilege hereunder shall operate as a waiver thereof nor
shall any single or partial exercise thereof preclude any other or further
exercise thereof or the exercise of any other right, power, or privilege. The
provisions of this Agreement may not be waived except by an instrument in
writing signed by or on behalf of the party against whom such waiver is sought
to be enforced.

ARTICLE X
MISCELLANEOUS

        10.1    Notices.    All notices, requests, demands, and other
communications required or permitted to be given or made hereunder by any party
hereto shall be in writing and shall be deemed to have been duly given or made
if (i) delivered personally, (ii) sent by prepaid overnight courier service, or
(iii) sent by telecopy or facsimile transmission, answer back requested, to the
parties at the following addresses (or at such other addresses as shall be
specified by the parties by like notice):

(a) If to the Company:

Brigham Exploration Company
6300 Bridge Point Parkway

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Building 2, Suite 500
Austin, TX 78730
Attention: Chief Financial Officer
Telefax: 512-427-3400

with a copy to:
Thompson & Knight L.L.P.
1700 Pacific Avenue, Suite 3300
Dallas, Texas 75201
Attention: Joe Dannenmaier
Telefax: 214-969-1751

(b) If to the Investors at:

Global Energy Partners
1100 Louisiana Street
Houston, Texas 77002
Fax: 713-890-1429
Attn: Steven A. Webster

and

CSFB Private Equity
11 Madison Avenue
New York, New York 10010
Fax: 917-326-8076
Attn: Ivy Dodes

with a copy to:
Gardere Wynne Sewell, LLP
1000 Louisiana, Suite 3400
Houston, Texas 77002
Attention: N.L. Stevens III
Telefax: 713-276-5807

Such notices, requests, demands, and other communications shall be effective
(i) if delivered personally or sent by courier service, upon actual receipt by
the intended recipient, or (ii) if sent by telecopy or facsimile transmission,
when the answer back is received.

        10.2    Entire Agreement.    This Agreement, together with the
Schedules, Exhibits, Annexes, and other writings referred to herein or delivered
pursuant hereto, constitutes the entire agreement between the parties hereto
with respect to the subject matter hereof and supersedes all prior agreements
and understandings, both written and oral, between the parties and their
Affiliates with respect to the subject matter hereof.

        10.3    Binding Effect; Assignment; No Third Party Benefit.    This
Agreement shall be binding upon and inure to the benefit of the parties hereto
and their respective successors and permitted assigns. Except as otherwise
expressly provided in this Agreement, neither this Agreement nor any of the
rights, interests or obligations hereunder shall be assigned by any of the
parties hereto without the prior written consent of the other party. Nothing in
this Agreement, express or implied, is intended to or shall confer upon any
person other than the parties hereto, and their respective heirs, legal
representatives, successors, and permitted assigns, any rights, benefits or
remedies of any nature whatsoever under or by reason of this Agreement.

        10.4    Severability.    If any provision of this Agreement is held to
be unenforceable, then this Agreement shall be considered divisible and such
provision shall be deemed inoperative to the extent it

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is deemed unenforceable, and in all other respects this Agreement shall remain
in full force and effect to the maximum extent permitted by Applicable Law.

        10.5    Injunctive Relief.    The parties hereto acknowledge and agree
that irreparable damage would occur in the event any of the provisions of this
Agreement were not performed in accordance with their specific terms or were
otherwise breached. It is accordingly agreed that the parties shall be entitled
to an injunction or injunctions to prevent breaches of the provisions of this
Agreement, and shall be entitled to enforce specifically the provisions of this
Agreement, in any court of the United States or any state thereof having
jurisdiction, in addition to any other remedy to which the parties may be
entitled under this Agreement or at law or in equity.

        10.6    Governing Law.    THIS AGREEMENT SHALL BE GOVERNED BY AND
CONSTRUED AND ENFORCED IN ACCORDANCE WITH THE LAWS OF THE STATEOF NEW YORK,
WITHOUT REGARD TO THE PRINCIPLES OF CONFLICTS OF LAWS THEREOF.

        10.7    Jurisdiction.    Except as otherwise expressly provided in this
Agreement, any suit, action or proceeding seeking to enforce any provision of,
or based on any matter arising out of or in connection with, this Agreement or
the transactions contemplated hereby may be brought in the United States
District Court for the Southern District of New York or any other New York State
court sitting in New York City, and each of the parties hereby consents to the
jurisdiction of such courts (and of the appropriate appellate courts therefrom)
in any such suit, action or proceeding and irrevocably waives, to the fullest
extent permitted by law, any objection which it may now or hereafter have to the
laying of the venue of any such suit, action or proceeding in any such court or
that any such suit, action or proceeding which is brought in any such court has
been brought in an inconvenient forum. Process in any such suit, action or
proceeding may be served on any party anywhere in the world, whether within or
without the jurisdiction of any such court. Without limiting the foregoing, each
party agrees that service of process on such party as provided in Section 10.01
shall be deemed effective service of process on such party.

        10.8    Counterparts.    This Agreement may be executed by the parties
hereto in any number of counterparts, each of which shall be deemed an original,
but all of which shall constitute one and the same agreement. Each counterpart
may consist of a number of copies hereof each signed by less than all, but
together signed by all, the parties hereto.

ARTICLE XI
DEFINITIONS

        11.1    Certain Defined Terms.    As used in this Agreement, each of the
following terms has the meaning given it in this Article:

        "Affiliate" of any Person shall mean (i) any Person directly or
indirectly controlled by, controlling or under common control with such first
Person, (ii) any director or officer of such first Person or of any Person
referred to in clause (i) above and (iii) if any Person in clause (i) above is
an individual, any member of the immediate family (including parents, spouse and
children) of such individual and any trust whose principal beneficiary is such
individual or one or more members of such immediate family and any Person who is
controlled by any such member or trust. For purposes of this definition, any
Person which owns directly or indirectly 50% or more of the securities having
ordinary voting power for the election of directors or other governing body of a
corporation or 50% or more of the partnership or other ownership interests of
any other Person (other than as a limited partner of such other Person) will be
deemed to "control" (including, with its correlative meanings, "controlled by"
and "under common control with") such corporation or other Person.

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        "Ancillary Documents" means each agreement, instrument, and document
(other than this Agreement) executed or to be executed by the Company or any
Investor in connection with the sale and purchase of the Shares and Warrants and
the other transactions contemplated by this Agreement.

        "Applicable Law" means any statute, law, rule, or regulation or any
judgment, order, writ, injunction, or decree of any Governmental Entity to which
a specified person or property is subject.

        "Assignment Agreement" means the Assignment Agreement dated as of
November 21, 2002, by and between Shell Capital Inc. as Assignor and the
Investors as Assignees.

        "BOG" means Brigham Oil & Gas, L.P.

        "Business Day" shall mean any day other than a Saturday, a Sunday, or a
day on which banking institutions in Austin, Texas are authorized or obligated
by law or executive order to close.

        "Code" shall mean the Internal Revenue Code of 1986, as amended from
time to time and any successor statute.

        "Common Stock" means the common stock, par value of $.01 per share, of
the Company, and such other class of securities as shall represent the common
equity of the Company.

        "Debt" shall mean, for any Person the sum of the following (without
duplication): (i) all obligations of such Person for borrowed money or evidenced
by bonds, debentures, notes or other similar instruments (including principal,
interest, fees and charges); (ii) all obligations of such Person (whether
contingent or otherwise) in respect of bankers acceptances, letters of credit,
surety or other bonds and similar instruments; (iii) all obligations of such
Person to pay the deferred purchase price of Property or services (other than
for borrowed money) excluding Trade Payables; (iv) all obligations under leases
which shall have been, or should have been, in accordance with GAAP, recorded as
capital leases in respect of which such Person is liable (whether contingent or
otherwise); (v) all obligations under leases (other than capital leases and oil
and gas leases) which require such Person or its Affiliate to make payments
exceeding $100,000 over the term of such lease, including payments at
termination, which are substantially equal to at least eighty percent (80%) of
the purchase price of the Property subject to such lease plus interest at an
imputed market rate of interest; (vi) all Debt (as described in the other
clauses of this definition) of others secured by a Lien on any asset of such
Person, whether or not such Debt is assumed by such Person; (vii) all Debt (as
described in the other clauses of this definition) of others guaranteed by such
Person or in which such Person otherwise assures a creditor against loss of the
Debt of others; (viii) all obligations or undertakings of such Person to
maintain or cause to be maintained the financial position or covenants of others
including without limitation agreements expressed as an agreement to purchase
the Debt or Property of others or otherwise; (x) obligations to pay for goods or
services whether or not such goods or services are actually received or utilized
by such Person; (xi) any capital stock of such Person in which such Person has a
mandatory obligation to redeem such stock; (xii) the undischarged balance of any
production payment created by such Person or for the creation of which such
Person directly or indirectly received payment; and (xiii) all obligations of
such Person under Hedging Agreements.

        "Encumbrances" means liens, charges, pledges, options, mortgages, deeds
of trust, security interests, claims, restrictions (whether on voting, sale,
transfer, disposition, or otherwise), easements, and other encumbrances of every
type and description, whether imposed by law, agreement, understanding, or
otherwise.

        "Environmental Laws" shall mean any and all Governmental Requirements
pertaining to the environment in effect in any and all jurisdictions in which
the Company or any Subsidiary is conducting or at any time has conducted
business, or where any Oil and Gas Property of the Company or any Subsidiary is
located, including without limitation, the Oil Pollution Act of 1990 ("OPA"),
the Clean Air Act, as amended, the Comprehensive Environmental, Response,
Compensation, and Liability Act of

21

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1980 ("CERCLA"), as amended, the Federal Water Pollution Control Act, as
amended, the Occupational Safety and Health Act of 1970, as amended, the
Resource Conservation and Recovery Act of 1976 ("RCRA"), as amended, the Safe
Drinking Water ACT, as amended, the Toxic Substances Control Act, as amended,
the Superfund Amendments and Reauthorization Act of 1986, as amended, the
Hazardous Materials Transportation Act, as amended, and other environmental
conservation or protection laws. As used in the provisions hereof relating to
Environmental Laws, the term "oil" shall have the meaning specified in OPA, the
terms "hazardous substance" and "release" (or "threatened release") have the
meanings specified in CERCLA, and the terms "solid waste" and "disposal" (or
"disposal") have the meanings specified in RCRA; provided that to the extent the
laws of the state in which any Oil and Gas Property of the Company or any
Subsidiary is located establish a meaning for "oil", "hazardous substance,"
"release," "solid waste" or "disposal" which is broader than that specified in
either OPA, CERCLA or RCRA, such broader meaning shall apply.

        "ERISA" shall mean the Employee Retirement Income Security Act of 1974,
as amended from time to time and any successor statute.

        "ERISA Affiliate" shall mean each trade or business (whether or not
incorporated) which together with the Company or any Subsidiary of the Company
would be deemed to be a "single employer" within the meaning of
section 4001(b)(1) of ERISA or subsections (b), (c), (m) or (o) of section 414
of the Code.

        "ESC" means DLJ ESC II, LP, a Delaware limited partnership.

        "Excepted Liens" shall mean: (i) Liens for taxes, assessments or other
governmental charges or levies not yet due or which are being contested in good
faith by appropriate action and for which adequate reserves have been maintained
in accordance with GAAP; (ii) Liens in connection with workmen's compensation,
unemployment insurance or other social security, old age pension or public
liability obligations not yet due or which are being contested in good faith by
appropriate action and for which adequate reserves have been maintained in
accordance with GAAP; (iii) operators', vendors', carriers', warehousemen's,
repairmen's, mechanics', workmen's, materialmen's, construction or other
likeLiensarising by operation of law in the ordinary course of business or
incident to the exploration, development, operation and maintenance of Oil and
Gas Properties or customary landlord's liens, each of which is in respect of
obligations that have not been outstanding more than 90 days or which are being
contested in good faith by appropriate proceedings and for which adequate
reserves have been maintained in accordance with GAAP; (iv) any Liens reserved
in leases or farmout agreements for rent or royalties and for compliance with
the terms of the farmout agreements or leases in the case of leasehold estates,
to the extent that any such Lien referred to in this clause does not materially
impair the use of the property covered by such Lien for the purposes for which
such property is held or materially impair the value of such property subject
thereto; (v) encumbrances (other than to secure the payment of borrowed money or
the deferred purchase price of property or services), easements, restrictions,
servitudes, permits, conditions, covenants, exceptions or reservations in any
rights of way or other property for the purpose of roads, pipelines,
transmission lines, transportation lines, distribution lines for the removal of
gas, oil, coal or other minerals or timber, and other like purposes, or for the
joint or common use of real estate, rights of way, facilities and equipment, and
defects, irregularities, zoning restrictions and deficiencies in title of any
rights of way or other property which in the aggregate do not materially impair
the use of such rights of way or other property for the purposes of which such
rights of way and other property are held or materially impair the value of such
property subject thereto; (vi) deposits of cash or securities to secure the
performance of bids, trade contracts, leases, statutory obligations and other
obligations of a like nature incurred in the ordinary course of business; and
(vii) Liens (including "Excepted Liens") permitted by or created pursuant to the
Senior Credit Agreement and Liens permitted by or created pursuant to the
Subordinated Credit Agreement.

        "Exchange Act" means the Securities Exchange Act of 1934, as amended.

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        "First Purchase Agreement" means that certain Securities Purchase
Agreement dated as of November 1, 2000, between the Company, MB and ESC.

        "Governmental Entity" means any court or tribunal in any jurisdiction
(domestic or foreign) or any public, governmental, or regulatory body, agency,
department, commission, board, bureau, or other authority or instrumentality
(domestic or foreign).

        "Governmental Requirement" shall mean any law, statute, code, ordinance,
order, determination, rule, regulation, judgment, decree, injunction, franchise,
permit, certificate, license, authorization or other directive or requirement
(in the case of banking regulatory authorities whether or not having the force
of law), including, without limitation, Environmental Laws, energy regulations
and occupational, safety and health standards or controls, of any Governmental
Entity.

        "Hedging Agreements" shall mean any commodity, interest rate or currency
swap, cap, floor, collar, forward agreement or other exchange or protection
agreements or any option with respect to any such transaction.

        "HSR Act" means the Hart-Scott-Rodino Antitrust Improvements Act of
1976, as amended.

        "Hydrocarbon Interests" shall mean all rights, titles, interests and
estates now or hereafter acquired in and to oil and gas leases, oil, gas and
mineral leases, or other liquid or gaseous hydrocarbon leases, mineral fee
interests, overriding royalty and royalty interests, net profit interests and
production payment interests, including any reserved or residual interests of
whatever nature.

        "Hydrocarbons" shall mean oil, gas, casinghead gas, drip gasoline,
natural gasoline, condensate, distillate, liquid hydrocarbons, gaseous
hydrocarbons and all products refined or separated therefrom.

        "Lien" shall mean any interest in property securing an obligation owed
to, or a claim by, a person other than the owner of the property, whether such
interest is based on the common law, statute or contract, and whether such
obligation or claim is fixed or contingent, and including but not limited to
(i) the lien or security interest arising from a mortgage, encumbrance, pledge,
security agreement, conditional sale or trust receipt or a lease, consignment or
bailment for security purposes or (ii) production payments and the like payable
out of Oil and Gas Properties. The term "Lien" shall include reservations,
exceptions, encroachments, easements, rights of way, covenants, conditions,
restrictions, leases and other title exceptions and encumbrances affecting
property. For the purposes of this Agreement, a Person shall be deemed to be the
owner of any property which it has acquired or holds subject to a conditional
sale agreement, or leases under a financing lease or other arrangement pursuant
to which title to the Property has been retained by or vested in some other
Person in a transaction intended to create a financing.

        "Material Adverse Effect" means, relative to the Company or the
Investors, as the case may be, any change, development, or effect (individually
or in the aggregate) which is, or is reasonably likely to be, materially adverse
(i) to the business, assets, results of operations, condition (financial or
otherwise), or prospects of the Company and the Subsidiaries considered as a
whole, or the Investors, as the case may be, or (ii) to the ability of the
Company or the Investors, as the case may be, to perform on a timely basis any
material obligation of the Company or the Investors, as the case may be, under
this Agreement or any agreement, instrument, or document entered into or
delivered in connection herewith.

        "Material Agreement" means (a) any written agreement, contract, lease,
commitment, understanding, instrument or obligation to which the Company or any
Subsidiary is a party or by which the Company or any Subsidiary or any of their
respective properties may be bound involving total value or consideration or
liability in excess of $500,000, (b) any loan or credit agreement, bond,
debenture, note, mortgage or indenture by which the Company or any Subsidiary or
any of their respective

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properties may be bound, or (c) any agreement set forth as an exhibit to the
Company's Form 10-K for the fiscal year ended December 31, 2001.

        "MB" means DLJMB Funding III, Inc., a Delaware corporation.

        "Oil and Gas Properties" shall mean Hydrocarbon Interests; the
Properties now or hereafter pooled or unitized with Hydrocarbon Interests; all
presently existing or future unitization, pooling agreements and declarations of
pooled units and the units created thereby (including without limitation all
units created under orders, regulations and rules of any Governmental Authority)
which may affect all or any portion of the Hydrocarbon Interests; all operating
agreements, contracts and other agreements which relate to any of the
Hydrocarbon Interests or the production, sale, purchase, exchange or processing
of Hydrocarbons from or attributable to such Hydrocarbon Interests; all
Hydrocarbons in and under and which may be produced and saved or attributable to
the Hydrocarbon Interests, including all oil in tanks, the lands covered thereby
and all rents, issues, profits, proceeds, products, revenues and other incomes
from or attributable to the Hydrocarbon Interests; all tenements, hereditaments,
appurtenances and Properties in any manner appertaining, belonging, affixed or
incidental to the Hydrocarbon Interests; and all Properties, rights, titles,
interests and estates described or referred to above, including any and all
Property, real or personal, now owned or hereinafter acquired and situated upon,
used, held for use or useful in connection with the operating, working or
development of any of such Hydrocarbon Interests or Property (excluding drilling
rigs, automotive equipment or other personal property which may be on such
premises for the purpose of drilling a well or for other similar temporary uses)
and including any and all oil wells, gas wells, injection wells or other wells,
buildings, structures, fuel separators, liquid extraction plants, plant
compressors, pumps, pumping units, field gathering systems, tanks and tank
batteries, fixtures, valves, fittings, machinery and parts, engines, boilers,
meters, apparatus, appliances, tools, implements, cables, wires, towers, casing,
tubing and rods, similar equipment, surface leases, rights-of-way, easements and
servitudes together with all additions, substitutions, replacements, accessions
and attachments to any and all of the foregoing.

        "Person" or "person" means any individual, corporation, partnership,
joint venture, association, joint-stock company, trust, enterprise,
unincorporated organization, or Governmental Entity.

        "Plan" shall mean any employee pension benefit plan, as defined in
Section 3(2) of ERISA, which (i) is currently or hereafter sponsored, maintained
or contributed to by the Company, any Subsidiary or an ERISA Affiliate or
(ii) was at any time during the preceding six calendar years sponsored,
maintained or contributed to, by the Company, any Subsidiary or an ERISA
Affiliate.

        "Proceeding" means any action, suit or proceeding, whether civil,
criminal, administrative, arbitrative or investigative, any appeal in such an
action, suit or proceeding, and any inquiry or investigation that could lead to
such an action, suit or proceeding.

        "Reasonable best efforts" means a party's best efforts in accordance
with reasonable commercial practice and without the incurrence of unreasonable
expense.

        "Rule 144" means Rule 144 promulgated under the Securities Act.

        "Second Purchase Agreement" means that certain Securities Purchase
Agreement dated as of March 5, 2001, between the Company, MB, MBP, DOP and ESC.

        "Securities Act" means the Securities Act of 1933, as amended.

        "Senior Credit Agreement" means that certain Amended and Restated Credit
Agreement dated as of February 17, 2000, by and between BOG, Bank of Montreal,
as Agent, and the Lenders signatory thereto, as amended on October 31, 2000,
together with the "Loan Documents" described therein.

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        "Subordinated Credit Agreement" means the Subordinated Credit Agreement
dated as of October 31, 2000 by and between BOG, Shell Capital, Inc., as Agent,
and the Lenders signatory thereto, together with the "Loan Documents" described
therein.

        "Subsidiaries" means Brigham Oil & Gas, L.P.; Brigham, Inc.; Brigham
Holdings I, LLC and Brigham Holdings II, LLC.

        "to the best of the Company's knowledge" and similar references to the
knowledge of the Company mean the actual knowledge of the executive officers and
senior management personnel of the Company after making a reasonable inquiry of
individuals responsible for the particular matter.

        "Voting Securities" means shares of Common Stock and any other
securities of the Company entitled to vote generally for the election of
directors or any other securities (including, without limitation, rights,
warrants, and options) convertible into or exchangeable or exercisable for any
of the foregoing (whether or not presently convertible, exchangeable, or
exercisable).

        IN WITNESS WHEREOF, the parties have executed this Agreement, or caused
this Agreement to be executed by their duly authorized representatives, all as
of the day and year first above written.

 
 
THE COMPANY:
 
 
BRIGHAM EXPLORATION COMPANY
 
 
By:
/s/  DAVID T. BRIGHAM              

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        Name: David T. Brigham

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        Title: Executive Vice President—Land and Administration

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INVESTORS:
 
 
DLJ MERCHANT BANKING PARTNERS III, L.P.
 
 
By: DLJ MERCHANT BANKING III, INC.,
its Managing General Partner
 
 
By:
 
/s/  ROBERT CABES      
 
     

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        ROBERT CABES
        Attorney-in-Fact    
DLJ MERCHANT BANKING III, INC., AS ADVISORY
GENERAL PARTNER ON BEHALF OF
DLJ OFFSHORE PARTNERS III, C.V.
By:
 
/s/  ROBERT CABES      
 
     

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        ROBERT CABES
        Attorney-in-Fact    

25

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DLJ MERCHANT BANKING III, INC.,
AS ADVISORY GENERAL PARTNER ON BEHALF OF
DLJ OFFSHORE PARTNERS III-1, C.V. AND AS
ATTORNEY-IN-FACT FOR DLJ MERCHANT BANKING III, L.P.,
AS ASSOCIATE GENERAL PARTNER OF
DLJ OFFSHORE PARTNERS III-1, C.V. By:   /s/  ROBERT CABES              

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        ROBERT CABES
        Attorney-in-Fact     DLJ MERCHANT BANKING III, INC., AS ADVISORY
GENERAL PARTNER ON BEHALF OF
DLJ OFFSHORE PARTNERS III-2, C.V. AND
AS ATTORNEY-IN-FACT FOR DLJ MERCHANT BANKING III, L.P.,
AS ASSOCIATE GENERAL PARTNER OF
DLJ OFFSHORE PARTNERS III-2, C.V. By:   /s/  ROBERT CABES              

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        ROBERT CABES
        Attorney-in-Fact     DLJ MB PARTNERS III GmbH & CO. KG     By:   DLJ
MERCHANT BANKING III, L.P.,
its Managing Limited Partner     By:   DLJ MERCHANT BANKING III, INC.,
its General Partner       By:   /s/  ROBERT CABES              

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ROBERT CABES
Attorney-in-Fact     MILLENNIUM PARTNERS II, L.P.     By:   DLJ MERCHANT BANKING
III, INC.,
its Managing General Partner       By:   /s/  ROBERT CABES                

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ROBERT CABES
Attorney-in-Fact     MBP III PLAN INVESTORS, L.P.     By:   DLJ LBO PLANS
MANAGEMENT CORPORATION,
its Managing General Partner       By:   /s/  ROBERT CABES                

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ROBERT CABES
Attorney-in-Fact
   

26

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SCHEDULE A

Name

--------------------------------------------------------------------------------

  No. of
Shares

--------------------------------------------------------------------------------

  No. of
Warrants

--------------------------------------------------------------------------------

DLJ Merchant Banking Partners III, L.P.   360,450   1,657,241
DLJ Merchant Banking III, Inc., as Advisory General Partner on behalf of DLJ
Offshore Partners III, C.V.
 
19,632
 
90,262
DLJ Merchant Banking III, Inc., as Advisory General Partner on behalf of DLJ
Offshore Partners III-1, C.V. and as attorney-in-fact for DLJ Merchant
Banking III, L.P., as Associate General Partner of DLJ Offshore Partners III-1,
C.V.
 
6,571
 
30,211
DLJ Merchant Banking III, Inc., as Advisory General Partner on behalf of DLJ
Offshore Partners III-2, C.V. and as attorney-in-fact for DLJ Merchant
Banking III, L.P., as Associate General Partner of DLJ Offshore Partners III-2,
C.V.
 
4,681
 
21,522
DLJ MB PartnersIII GmbH & Co. KG
 
3,106
 
14,280
Millennium Partners II, L.P.
 
626
 
2,878
MBP III Plan Investors, L.P.
 
104,934
 
482,456

27

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QuickLinks

Exhibit 10.49

SECURITIES PURCHASE AGREEMENT
ARTICLE I TERMS OF THE TRANSACTION
ARTICLE II CLOSING
ARTICLE III REPRESENTATIONS AND WARRANTIES OF THE COMPANY
ARTICLE IV REPRESENTATIONS AND WARRANTIES OF INVESTORS
ARTICLE V ADDITIONAL AGREEMENTS
ARTICLE VI CONDITIONS TO OBLIGATIONS OF THE COMPANY
ARTICLE VII CONDITIONS TO OBLIGATIONS OF INVESTORS
ARTICLE VIII COVENANTS
ARTICLE IX AMENDMENT AND WAIVER
ARTICLE X MISCELLANEOUS
ARTICLE XI DEFINITIONS
SCHEDULE A