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Exhibit 10.48

OMNIBUS AGREEMENT

        This Omnibus Agreement (this "Agreement"), dated as of December 20,
2002, is by and among Brigham Exploration Company, a Delaware corporation (the
"Company"), Brigham Oil & Gas, L.P., a Delaware limited partnership (the
"Borrower"), and the Credit Suisse First Boston entities listed on Schedule A
hereto (the "CSFB Entities"). Unless otherwise defined herein, all terms used
herein shall have the meaning given such terms in the Credit Agreement (defined
herein).

RECITALS

        WHEREAS, the CSFB Entities and Shell Capital Inc., a Delaware
corporation ("SCI") are parties to that certain Assignment Agreement, dated as
of November 21, 2002 (the "Assignment Agreement"), pursuant to which the CSFB
Entities purchased the Assigned Interest (as such term is defined in the
Assignment Agreement) (the "Assignment") held by SCI pursuant to that certain
Amended and Restated Credit Agreement, dated as of February 17, 2000, among the
Borrower, Agent, and each of the Lenders (as amended and supplemented, the
"Credit Agreement");

        WHEREAS, the parties desire that the CSFB Entities immediately convert
all outstanding Loans acquired by the CSFB Entities pursuant to the Assignment
Agreement into 2,564,102 shares of the Company's common stock, $0.01 par value
(the "Shares"), in accordance with the Equity Conversion Agreement (the
"Conversion");

        WHEREAS, the parties desire to waive certain actions required under the
Credit Agreement or other Loan Documents in order to effect the Conversion in an
expedient manner; and

        WHEREAS, the Company, the Borrower and SCI are parties to that certain
Exchange Agreement, dated as of November 21, 2002 (the "Exchange Agreement"),
pursuant to which certain of the Loan Documents will be amended or terminated;

        NOW, THEREFORE, in consideration of the mutual representations,
covenants, and agreements contained herein, the parties hereto, intending to be
legally bound, hereby agree as follows:

        1.    No Liability; Release. The Company and the Borrower agree that,
upon completion of the Assignment and the Conversion, the CSFB Entities will not
be a party to the Credit Agreement or any of the Loan Documents, and effective
as of such time, the Company and the Borrower hereby release and indemnify the
CSFB Entities from any liability of any kind thereunder (whether for matters
occurring before or after the Conversion). The CSFB Entities acknowledge and
agree that, upon completion of the Assignment and Conversion, they will have no
further rights or obligations under the Credit Agreement or any of the Loan
Documents and will cease to be a party under the Loan Documents.

        2.    Waiver of Delivery of Notes to the CSFB Entities. The CSFB
Entities hereby irrevocably waive the requirement under Section 12.06(d) of the
Credit Agreement that the Borrower deliver new Notes representing the principal
amount of the CSFB Entities' Maximum Credit Amount following the Assignment.

        3.    Conversion; Delivery of Stock Certificates. On the Closing Date
(as defined in the Assignment Agreement), the Company shall deliver stock
certificates representing the Shares to the CSFB Entities in accordance with the
allocations set forth in Schedule A hereto. The CSFB Entities shall not be
required to present a Note representing the outstanding Loans owned in order to
effect the Conversion.

        4.    Waiver of Conversion Notice. The Company and the Borrower hereby
irrevocably waive any requirement under the Equity Conversion Agreement,
including but not limited to Section 2.01(h) thereof, to provide any notice of
the Conversion.

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        5.    Inducement Payment. The Company shall pay the CSFB Entities the
sum of Five Hundred Thousand Dollars ($500,000) on the Closing Date as an
inducement by the Company to the CSFB Entities to exercise their conversion
rights under the Equity Conversion Agreement. In addition, the Company shall pay
or reimburse all reasonable out-of-pocket expenses incurred by the CSFB
Entities, including attorneys' fees, in connection with the transactions
contemplated by the Assignment Agreement or this Agreement.

        6.    Conditions Precedent. The effectiveness of this Agreement is
subject to the execution and delivery of a consent and waiver letter executed by
the Company, the Borrower, Agent and each of the Lenders in the form attached
hereto as Exhibit A.

        7.    Notices. All notices and other communications provided for herein
(including, without limitation, any modifications of, or waivers, requests or
consents under, this Agreement) shall be given or made in writing (including,
without limitation, by telex or telecopy) to the intended recipient at its
"Address for Notices" specified below its name on the signature pages hereof or,
as to either party, at such other address as shall be designated by such party
in a notice to the other party.

        8.    Amendment, Modification or Waiver. No provision of this Agreement
may be amended, modified or waived except by an instrument in writing signed by
the parties.

        9.    Successors and Assigns. This Agreement shall be binding upon and
inure to the benefit of the parties hereto and their respective successors and
assigns.

        10.  Governing Law. This Agreement shall be, in accordance with New York
General Obligations Law Section 5-1401, governed by and construed in accordance
with the laws of the State of New York.

        11.  Headings. The section headings appearing herein are included solely
for convenience of reference and are not intended to affect the interpretation
of any provision of this Agreement.

        12.  Counterparts. This Agreement may be executed in any number of
counterparts, each of which shall be identical and all of which, taken together,
shall constitute one and the same instrument, and each of the parties hereto may
execute this Agreement by signing any such counterpart.

[REMAINDER OF PAGE INTENTIONALLY LEFT BLANK.]

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

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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Address for Notice:
6300 Bridge Point Parkway

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Building Two, Suite 500

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Austin, TX 78730

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BRIGHAM OIL & GAS, L.P.
 
 
 
By:
/s/  BRIGHAM, INC.      

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      Its General Partner    
 
 
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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Address for Notice:
6300 Bridge Point Parkway

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Building Two, Suite 500

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Austin, TX 78730

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CSFB ENTITIES:
 
 
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
 
 

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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
 
 
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
 
 

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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
 
 
ADDRESSES FOR NOTICES TO THE CSFB ENTITIES:
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: 212-448-3502
Attn: Dorian S. Forshner

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SCHEDULE A

Holder Name

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  No. of Shares

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DLJ Merchant Banking Partners III, L.P.
 
1,848,463
DLJ Merchant Banking III, Inc., as Advisory General Partner on behalf of DLJ
Offshore Partners III, C.V.
 
100,675
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.
 
33,699
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.
 
24,005
DLJ MB Partners III GmbH & Co. KG
 
15,926
Millennium Partners II, L.P.
 
3,210
MBP III Plan Investors, L.P.
 
538,124

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EXHIBIT A

[Brigham Exploration Company Letterhead]

Bank of Montreal
700 Louisiana Street, Suite 4400
Houston, Texas 77002

Societe Generale
1111 Bagby Street, Suite 2020
Houston, Texas 77002

Shell Capital Inc.
910 Louisiana Street, Suite 5000
Houston, Texas 77002

The Royal Bank of Scotland plc
600 Travis Street, Suite 6070
Houston, Texas 77002

Re: Consent and Waiver Request

Gentlemen and Ladies:

        Reference is made to (a) the Amended and Restated Credit Agreement dated
as of February 17, 2000 (as amended to date, the "Senior Credit Agreement")
among Brigham Oil & Gas, L.P., as Borrower ("Borrower"), Bank of Montreal, as
Agent (in such capacity, "Senior Agent", and individually, "BMO"), and BMO,
Societe Generale ("Soc Gen"), and Shell Capital Inc. ("SCI"), as Lenders, and
(b) the Subordinated Credit Agreement dated as of October 31, 2000 (as amended
to date, the "Subordinated Credit Agreement") as originally between Borrower and
SCI and now among Borrower, the Royal Bank of Scotland plc, as Agent (as
successor to SCI), and the Lenders signatory thereto.

        As used in this consent and waiver letter, "Loan Documents" means the
"Loan Documents" as defined in either the Senior Credit Agreement or the
Subordinated Credit Agreement, and "Brigham" means Brigham Exploration Company.

        Brigham and Borrower intend to participate in the transactions or enter
into the agreements (a copy of each of which is attached hereto) described
below:

        1.    a certain Assignment Agreement dated as of November 21, 2002 (the
"Assignment Agreement") between SCI, DLJ Merchant Banking Partners III, L.P. and
various other affiliates of, or entities otherwise associated with, Credit
Suisse First Boston (collectively, "CSFB") pursuant to which, among other
things, SCI will assign to CSFB the principal amount of the loans outstanding
under the Senior Credit Agreement equal to $10,000,000 and the right to convert
such loans into common stock of Brigham pursuant to the Equity Conversion
Agreement dated as of February 17, 2000 (as amended to date, the "Equity
Conversion Agreement") among SCI, Brigham and Borrower;

        2.    a certain Omnibus Agreement by and among Brigham, the Borrower and
CSFB in the form attached to the Assignment Agreement, that provides, among
other things, for the exercise by CSFB of its conversion right (the "Note
Conversion") in accordance with the Equity Conversion Agreement, the payment of
$500,000 by Brigham to CSFB as an inducement to the Note Conversion, and the
consequent issuance of 2,564,102 shares of Brigham's common stock to CSFB;

        3.    a certain Exchange Agreement dated as of November 21, 2002 (the
"Exchange Agreement") by and between Brigham, the Borrower and SCI, pursuant to
which, among other things, Brigham will issue 550,000 shares of its common stock
to SCI, SCI will surrender all of its

A-1

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warrants issued by Brigham, and Brigham, the Borrower and SCI will terminate the
Equity Conversion Agreement and other documents described therein;

        4.    a certain Registration Rights Agreement between Brigham and SCI in
the form attached to the Exchange Agreement, pursuant to which SCI and its
successors and assigns will have "demand" and "piggy back" registration rights
to obtain registration of such 550,000 shares of common stock in certain
circumstances; and

        5.    the sale by Brigham to CSFB, for $10,000,000 in cash, of shares of
a new, mandatorily redeemable preferred stock plus new warrants to purchase
common stock of Brigham at $4.35 per share, as more fully described on Exhibit
A.

        As a result of these transactions, both the "Maximum Credit Amount" of
SCI under the Senior Credit Agreement and the principal balance of SCI's loans
under the Senior Credit Agreement will be reduced to $30,000,000, and, after
giving effect to the Note Conversion, CSFB will have no such "Maximum Credit
Amount".

        Please execute a copy of this consent and waiver letter in the space
provided below to evidence (a) your consent to the execution of the documents
described above and the consummation of the transactions therein and herein on
the terms described above, (b) your agreement that the Assignment Agreement and
the Note Conversion may be completed without any issuance of a new $10,000,000
promissory note to CSFB and without any surrender of such a note by CFSB to
Brigham or Borrower, (c) your agreement that, upon completion of the Assignment
Agreement and the Note Conversion, CSFB will not be a party to the Senior Credit
Agreement or any of the Loan Documents and your release of CSFB from any
liability of any kind thereunder (whether for matters occurring before or after
the Note Conversion), and (d) your agreement to confirm the foregoing in writing
directly to CSFB, if hereafter requested to do so.

        Brigham and Borrower hereby (x) waive any requirement in the Loan
Documents that the Senior Agent or SCI give either of them notice of any of the
transactions described above (whether under Section 12.06(d) of the Senior
Credit Agreement, under the Equity Conversion Agreement, or otherwise),
(y) agree to issue a new promissory note to SCI, in the stated amount of
$30,000,000, and (z) confirm to Senior Agent, BMO, Soc Gen and SCI that the Loan
Documents remain in full force and effect and (except as described in the
Exchange Agreement) will remain in full force and effect after giving effect to
the transactions described above.

        This consent and waiver letter shall be governed by and construed under
the laws of the State of Texas. This consent and waiver le tter may be executed
in multiple counterparts, and by the different parties hereto in separate
counterparts (which may be delivered, among other ways, by the exchange of faxed
signature pages), and all of such counterparts will constitute a single letter
agreement.

A-2

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        Thank you very much for your cooperation.

 
 
 
 
Yours truly,
 
 
 
 
BRIGHAM EXPLORATION COMPANY
 
 
 
 
By:
  

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          Name:               Title:    
 
 
 
 
BRIGHAM OIL & GAS, L.P.
 
 
 
 
By:
Brigham, Inc., its general partner
 
 
 
 
 
By:
  

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            Name:               Title:  
CONSENTED TO as of the date
set out above:
BANK OF MONTREAL, as Senior Agent and Lender
By:
  

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    Name:               Title:            
SOCIETE GENERALE
By:
  

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    Name:               Title:            
SHELL CAPITAL INC.
By:
  

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    Name:               Title:            
THE ROYAL BANK OF SCOTLAND plc
By:
  

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    Name: Peter Buchanan             Title: Director          

A-3

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EXHIBIT A

[Description of preferred stock and warrants to come based on final term sheet.]

A-4

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QuickLinks

Exhibit 10.48

OMNIBUS AGREEMENT
RECITALS
SCHEDULE A
EXHIBIT A
EXHIBIT A