XTO Energy Increases Proved Reserves to a Record 7.622 Tcfe, Up 30%

XTO Energy announced that Miller and Lents, Ltd., independent petroleum engineers, estimate XTO's proved oil and gas reserves at December 31, 2005 to be a record 7.622 trillion cubic feet of gas equivalent (Tcfe), up 30% compared with 5.860 Tcfe at December 31, 2004. Natural gas reserves increased 29% to 6.086 Tcf, and natural gas combined with natural gas liquids of 47 million barrels equaled 84% of total reserves. Oil reserves increased 37% to 209 million barrels. Proved developed reserves accounted for 69% of total proved reserves on an Mcfe basis.

During 2005, XTO Energy added 2.337 Tcfe at a cost of $1.44 per thousand cubic feet of gas equivalent (Mcfe), replacing 481% of production. Including asset retirement obligations, the cost rises to $1.47 per Mcfe. The Company's development program replaced 274% of production or 1.330 Tcfe at a cost of $1.12 per Mcfe.

Based on year-end prices of $9.26 per thousand cubic feet of gas (Mcf), $36.33 per barrel of natural gas liquids and $57.02 per barrel of oil and on constant cost assumptions, estimated future net cash flows, before income taxes, totaled $50.9 billion at December 31, 2005. The present value before income tax, discounted at 10%, was $25.8 billion, compared to $12.2 billion at year-end 2004. Year-end 2004 prices were $5.69 per Mcf of gas, $28.24 per barrel of natural gas liquids and $41.03 per barrel of oil.

XTO Energy Inc. is a domestic energy producer engaged in the acquisition, development and discovery of quality, long-lived oil and natural gas properties in the United States. Its properties are concentrated in Texas, New Mexico, Arkansas, Oklahoma, Kansas, Wyoming, Colorado, Alaska, Utah and Louisiana.


    Proved Oil and Gas Reserves
    December 31, 2005                Natural
    (in millions)            Gas   Gas Liquids    Oil
                            (Mcf)     (Bbls)     (Bbls)      BOE      Mcfe

    Proved Developed       4,033.1     36.5      168.5      877.1    5,262.9
    Proved Undeveloped     2,052.5     10.9       40.2      393.3    2,359.3

    Total Proved           6,085.6     47.4      208.7    1,270.4    7,622.2

    Estimated future net cash flows of proved
     reserves, before income tax (A)                      $50,897

    Present value of future net cash flows
     discounted at 10%, after income tax
     (or standardized measure disclosure under
     SFAS No. 69)                                         $17,094
    Add:  Present value of future income
     tax discounted at 10%                                  8,722

    Present value of future net cash flows
     discounted at 10% before income tax (A)              $25,816

    (A)  Management believes that pre-tax cash flow amounts are also useful
         for evaluative purposes since future income taxes, that are affected
         by a company's unique tax position and strategies, can make after-tax
         amounts less comparable.

    Changes in Proved Reserves        Natural
    (in millions)            Gas    Gas Liquids   Oil
                            (Mcf)     (Bbls)    (Bbls)        BOE     Mcfe

    December 31, 2004      4,714.5     38.5      152.5       976.7   5,860.3

    Revisions                  4.0      5.3       12.1        18.1     108.5
    Extensions and
     discoveries             986.6      4.9       34.2       203.5   1,221.2
    Production              (377.1)    (3.8)     (14.3)      (80.9)   (485.5)
    Purchases in place       803.4      2.8       31.1       167.9   1,007.1
    Sales in place           (45.8)    (0.3)      (6.9)      (14.9)    (89.4)

    December 31, 2005      6,085.6     47.4      208.7     1,270.4   7,622.2

    Acquisition, Development and Exploration Costs Incurred During 2005

    The following table summarizes costs incurred, whether such costs are
    capitalized or expensed for financial reporting purposes:

        (in millions)
              Proved properties                           $  1,710
              Unproved properties -
               acquisition of corporation (A)                  180
              Unproved properties - other                       92
        Development (B)                                      1,341
        Exploration ©                                         52
        Asset retirement obligation accrual                     53

        Total costs incurred disclosure under SFAS No. 69    3,428
        Asset retirement obligation accrual                    (53)

        Total costs incurred before asset
         retirement cost accrual (D)                      $  3,375

     (A)  Represents a portion of the allocated purchase price of Antero
          Resources Corporation.
     (B)  Includes $6 million of capitalized interest.
     ©  Primarily includes exploratory drilling, geological and geophysical
     (D)  For purposes of evaluating annual costs incurred, management
          excludes the asset retirement obligation accrual since these
          estimated costs are related to future activities, and are deducted
          in the calculation of estimated future net cash flows of proved