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                                                                   EXHIBIT 99.12


                                 March 26, 1999



Mr. Ron E. Hooper
Burlington Resources Coal Seam
   Gas Royalty Trust
NationsBank of Texas, N.A., Trustee
NationsBank Plaza
901 Main Street, 17th Floor
Dallas, Texas  75202

Dear Mr. Hooper:

         In accordance with your request, we have estimated, as of December 31,
1998, the Section 29 nonconventional fuels federal income tax credit
attributable to the Burlington Resources Coal Seam Gas Royalty Trust (Trust) net
profits interest in the Fruitland Coal Formation underlying the Northeast Blanco
Unit, Rio Arriba and San Juan Counties, New Mexico, as listed in the
accompanying tabulations. The tax credit is derived from the Burlington
Resources Oil & Gas Company (Burlington) interest in the proved gas reserves as
estimated in our report dated March 25, 1999. This report has been prepared
using constant prices and costs and conforms to the guidelines of the Securities
and Exchange Commission (SEC).

         The estimated net proved reserves in this report are defined as the
portion of the gross reserves attributable to the Trust net profits interest.
These reserves have been reduced by the amount of gas reserves necessary to
cover the lease operating costs at the current gas price. As presented in the
accompanying summary projection, Table I, we estimate the Trust net reserves and
the tax credit attributable to the Trust net profits interest, as of December
31, 1998, to be:

<TABLE>
<CAPTION>

                                        Trust Net Reserves                            Future Tax Credit
                                ------------------------------------      ------------------------------------------
                                  Condensate              Gas                                       Present Worth
        Category                  (Barrels)              (MCF)                  Total                  at 10%
--------------------------      ---------------      ---------------      ------------------      ------------------
<S>                            <C>                  <C>                   <C>                     <C>        
Proved Developed                      0                23,488,676            $22,267,800             $18,787,200
</TABLE>

         Gas volumes are expressed in thousands of standard cubic feet (MCF) at
the contract temperature and pressure bases. These properties no longer produce
commercial volumes of condensate.

         This report includes a summary projection of reserves and future tax
credit along with one-line summaries of reserves, economics, and basic data by
lease. For the purposes of this report, the term "lease" refers to a single
economic projection.

         The estimated reserves and future tax credit shown in this report are
for proved developed reserves only. Our study indicates that there are no proved
undeveloped reserves for these properties at 



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this time. In accordance with SEC guidelines, our estimates do not include any
value for probable or possible reserves which may exist for these properties.
This report does not include any value which could be attributed to interests in
undeveloped acreage.

         For the purposes of this report, a field inspection of the properties
has not been performed nor has the mechanical operation or condition of the
wells and their related facilities been examined. We have not investigated
possible environmental liability related to the properties; therefore, our
estimates do not include any costs which may be incurred due to such possible
liability. Also, our estimates do not include any salvage value for the lease
and well equipment nor the cost of abandoning the properties.

         The estimated 1998 tax credit rate used in this report is $1.07 per
MMBTU. This rate is held constant in accordance with SEC guidelines. The gas
price used in this report is based on the December 1998 price received, adjusted
for BTU content, the gathering fee, and shrinkage. This price is also adjusted
as specified in the gas purchase contract under provisions related to the
sharing price and price credit account and is held constant in accordance with
SEC guidelines.

         Lease and well operating costs are based on operating expense records
provided by Burlington and the Trustee. These costs include the per-well
overhead expenses allowed under joint operating agreements along with costs
estimated to be incurred at and below the district and field levels. General and
administrative overhead expenses of the Trustee are not included. Lease and well
operating costs are held constant in accordance with SEC guidelines. Capital
costs are included as required for workovers and production equipment.

         We have made no investigation of potential gas volume and value
imbalances which may have resulted from overdelivery or underdelivery to the
Burlington interest. Therefore, our estimates of reserves and tax credit do not
include adjustments for the settlement of any such imbalances; our projections
are based on Burlington receiving its net revenue interest share of estimated
future gross gas production.

         The reserves included in this report are estimates only and should not
be construed as exact quantities. They may or may not be recovered; if
recovered, the tax credit therefrom and the costs related thereto could be more
or less than the estimated amounts. The sales rates, prices received for the
reserves, and costs incurred in recovering such reserves may vary from
assumptions included in this report due to governmental policies and
uncertainties of supply and demand. Also, estimates of reserves may increase or
decrease as a result of future operations.

         In evaluating the information at our disposal concerning this report,
we have excluded from our consideration all matters as to which legal or
accounting, rather than engineering and geological, interpretation may be
controlling. As in all aspects of oil and gas evaluation, there are
uncertainties inherent in the interpretation of engineering and geological data;
therefore, our conclusions necessarily represent only informed professional
judgments.

         The titles to the properties have not been examined by Netherland,
Sewell & Associates, Inc., nor has the actual degree or type of interest owned
been independently confirmed. The data used in our 


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estimates were obtained from Burlington Resources Oil & Gas Company, the
Trustee, and the nonconfidential files of Netherland, Sewell & Associates, Inc.
and were accepted as accurate. We are independent petroleum engineers,
geologists, and geophysicists; we do not own an interest in these properties and
are not employed on a contingent basis. Basic geologic and field performance
data together with our engineering work sheets are maintained on file in our
office.

                                             Very truly yours,

                                             /s/ FREDERIC D. SEWELL


DDS:PJA