Exhibit 99.1
 Cawley, Gillespie & Associates, Inc.
  9601 AMBERGLEN BLVD., SUITE 117
    
    306 WEST SEVENTH STREET, SUITE 302
    
    1000 LOUISIANA STREET, SUITE 625AUSTIN, TEXAS 78729-1106
    
    FORT WORTH, TEXAS 76102-4987
    
    HOUSTON, TEXAS 77002-5008512-249-7000
FAX 512-233-2618
    
    817- 336-2461
FAX 817-877-3728
    
    713-651-9944
FAX 713-651-9980www.cgaus.com
  
 Re:
    
    Evaluation SummaryBrigham Oil & Gas, L. P. InterestsProved ReservesAs of December 31, 2010Pursuant to the Guidelines of the
Securities and Exchange Commission for
Reporting Corporate Reserves and
Future Net Revenue
  Securities and Exchange Commission




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Brigham Exploration Company (SEC Prices)
January 12, 2011
Page 2
  ProvedTotal
    
    
    Developed
    
    
    UndevelopedNet ReservesOil   bbl
    
    
    
    
    
    
    52,208,590
    
    
    
    17,521,908
    
    
    
    34,686,684Gas   Mcf
    
    
    
    
    
    
    87,821,742
    
    
    
    36,537,117
    
    
    
    51,284,617Net RevenueOil  $
    
    
    
    
    
    
    3,700,987,250
    
    
    
    1,244,022,375
    
    
    
    2,456,964,250Gas  $
    
    
    
    
    
    
    530,569,062
    
    
    
    207,980,250
    
    
    
    322,588,750Net BOE Production  BOE
    
    
    
    
    
    66,845,539
    
    
    
    23,611,428
    
    
    
    43,234,117Ad Valorem
Tax  $
    
    
    
    
    
    
    13,528,012
    
    
    
    6,550,199
    
    
    
    6,977,813Operating
Expense  $
    
    
    
    
    
    
    677,165,812
    
    
    
    259,770,875
    
    
    
    417,395,000Production
Severance Tax  $
    
    
    
    
    
    
    427,454,969
    
    
    
    144,554,531
    
    
    
    282,900,469Investments
 $
    
    
    
    
    
    
    770,356,562
    
    
    
    31,458,750
    
    
    
    738,897,812Future Net
Cash Flow  $
    
    
    
    
    
    
    2,344,497,750
    
    
    
    1,011,115,562
    
    
    
    1,333,382,250Discounted @ 10%
(Present Worth)  $
    
    
    
    
    
    
    1,108,685,000
    
    
    
    598,838,438
    
    
    
    509,846,438
    Hydrocarbon Pricing




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Brigham Exploration Company (SEC Prices)
January 12, 2011
Page 3
  SEC Conformance and Regulations
   Reserve Estimation Methods
   Economic Parameters




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Brigham Exploration Company (SEC Prices)
January 12, 2011
Page 4
 General Discussion
    Yours very truly,Cawley, Gillespie & Associates, Inc.Texas Registered Engineering Firm F-693(IMAGE)
    
    (-s- W. Todd Brooker)W. Todd Brooker, P. E.Vice President




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APPENDIX
 Explanatory Comments for Summary Tables
 HEADINGS
 
 FORECAST
  (1)(11)
    
    Calendar or Fiscal years/months commencing on effective date.(2)(3)
    
    Gross Production (8/8th) for the years/months which are economical. These are
expressed as thousands of barrels (Mbbl) and millions of cubic feet (MMcf) of gas at standard
conditions. Total future production, cumulative production to effective date, and ultimate
recovery at the effective date are shown following the annual/monthly forecasts. (Gross MBOE
is shown to right of Ultimate Recovery values in light gray font, calculated by dividing the
ultimate gross gas production by six (6) then adding to the ultimate gross oil production.)(4)(5)
    
    Net Production accruable to evaluated interest is calculated by multiplying the
revenue interest times the gross production. These values take into account changes in
interest and gas shrinkage.(6)
    
    Average (volume weighted) Gross Liquid Price per barrel adjusted for average
differential above or below Nymex, but before deducting production-severance taxes.
(Composite differential in $/bbl shown at left in light gray font)(7)
    
    Average (volume weighted) Gross Gas Price per Mcf adjusted for average differential
above or below Nymex, but before deducting production-severance taxes. (Composite
differential in $/mcf shown at left in light gray font)(8)
    
    Revenue derived from oil sales  column (4) times column (6).(9)
    
    Revenue derived from gas sales  column (5) times column (7).(10)
    
    Total Revenue  column (8) plus column (9).(11)
    
    Calendar or Fiscal years/months commencing on effective date.(12)
    
    Net MBOE Production (equivalent net oil production)  Accruable to evaluated
interest is calculated by dividing the net gas production by six (6) then adding to the net
oil production.(13)
    
    Ad Valorem Taxes.(14)
    
    Average Gross Wells.(15)
    
    Average Net Wells are gross wells times working interest.(16)
    
    Operating Expenses are direct operating expenses to the evaluated working interest.(17)
    
    Production Taxes  Severance Taxes deducted from gross oil and gas revenue.(18)
    
    Investment, if any, includes work-overs, future drilling costs, pumping units, etc.
and may be included either tangible or intangible or both.(19)
    
    Future Net Cash Flow is column (10) less columns (13), (16), (17) and (18). The
data in column (19) are accumulated in column (20). Federal income taxes have not been
considered.(20)
    
    Cumulative Future Net Cash Flow.(21)
    
    Cumulative Cash Flow Discounted @ 10% is calculated by discounting monthly
cash flows at the specified annual rates.
 MISCELLANEOUS
 DCF Profile
    
    
    
    The cash flow discounted at six different rates are shown at the bottom of
columns (20-21). Interest has been compounded monthly.Life
    
    
    
    The economic life of the appraised property is noted in the lower right-hand corner of the table.Footnotes
    
    
    
    Comments regarding the evaluation may be shown in the lower left-hand footnotes.Price Deck
    
    
    
    A table of oil and gas prices, price caps and escalation rates may be shown in the lower middle footnotes.
 AppendixCawley, Gillespie & Associates, Inc.
    
    Page 1




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APPENDIX
 Reserve Definitions and Classifications
  Proved oil and gas reserves
      Developed oil and gas reserves
   Undeveloped oil and gas reserves
    AppendixCawley, Gillespie & Associates, Inc.
    
    Page 2




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Probable reserves
     Possible reserves
       permitted, but not required
 Reserves
 Note to paragraph (26)
 AppendixCawley, Gillespie & Associates, Inc.
    
    Page 3




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APPENDIX
 Methods Employed in the Estimation of Reserves
 production
performance material balance volumetric analogy
 may
  Production performance
 Material balance
 Volumetric
 Analogy
  AppendixCawley, Gillespie & Associates, Inc.
    
    Page 4