<PAGE>
                       SECURITIES AND EXCHANGE COMMISSION
                             Washington, D.C. 20549



                                    Form 10-Q


                Quarterly Report Pursuant to Section 13 or 15(d)
                     of the Securities Exchange Act of 1934.


                For the Quarterly Period Ended September 30, 2001


                           Commission File No. 1-8032


                          SAN JUAN BASIN ROYALTY TRUST

              Texas                                              75-6279898
  (State or other jurisdiction                                (I.R.S. Employer
of incorporation or organization)                            Identification No.)


                         Bank One, NA, Trust Department
                                 P. O. Box 2604
                             Fort Worth, Texas 76113
                    (Address of principal executive offices)
                                   (Zip Code)

                          Telephone Number 817/884-4630
              (Registrant's telephone number, including area code)



Indicate by check mark whether the registrant (1) has filed all reports required
to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during
the preceding 12 months (or for such shorter period that the registrant was
required to file such reports) and (2) has been subject to such filing
requirements for the past 90 days. Yes [X] No [ ]

Number of Units of beneficial interest outstanding at November 12, 2001:
46,608,796



                                  Page 1 of 15
<PAGE>

                          SAN JUAN BASIN ROYALTY TRUST

                                     PART I
                              FINANCIAL INFORMATION

ITEM 1. FINANCIAL STATEMENTS.

The condensed financial statements included herein have been prepared by Bank
One, NA as Trustee for the San Juan Basin Royalty Trust (the "Trust"), without
audit, pursuant to the rules and regulations of the Securities and Exchange
Commission. Certain information and footnote disclosures normally included in
annual financial statements have been condensed or omitted pursuant to Rule
10-01 of Regulation S-X promulgated under the Securities and Exchange Act of
1934, although the Trustee believes that the disclosures are adequate to make
the information presented not misleading. These condensed financial statements
should be read in conjunction with the financial statements and the notes
thereto included in the Trust's annual report on Form 10-K for the year ended
December 31, 2000. In the opinion of the Trustee, all adjustments, consisting
only of normal recurring adjustments, necessary to present fairly the assets,
liabilities and trust corpus of the San Juan Basin Royalty Trust at September
30, 2001, and the distributable income and changes in trust corpus for the
three-month periods and nine-month periods ended September 30, 2001 and 2000
have been included. The distributable income for such interim periods is not
necessarily indicative of the distributable income for the full year.



                                       2
<PAGE>

SAN JUAN BASIN ROYALTY TRUST

CONDENSED STATEMENTS OF ASSETS, LIABILITIES AND TRUST CORPUS
--------------------------------------------------------------------------------

<Table>
<Caption>
                                                                         SEPTEMBER 30,     DECEMBER 31,
ASSETS                                                                        2001             2000
                                                                          (UNAUDITED)
<S>                                                                      <C>              <C>
Cash and short-term investments ......................................   $    3,196,224   $    6,972,892
Net overriding royalty interest in producing
   oil and gas properties (net of accumulated
   amortization of $95,216,461 and $92,588,674
   at September 30, 2001 and December 31, 2000, respectively) ........       38,059,067       40,686,854
                                                                         --------------   --------------

                                                                         $   41,255,291   $   47,659,746
                                                                         ==============   ==============
LIABILITIES AND TRUST CORPUS

Distribution payable to Unit holders .................................   $    3,196,224   $    6,972,892
Commitments and contingencies
Trust corpus - 46,608,796 Units of beneficial
   interest authorized and outstanding ...............................       38,059,067       40,686,854
                                                                         --------------   --------------

                                                                         $   41,255,291   $   47,659,746
                                                                         ==============   ==============
</Table>


CONDENSED STATEMENTS OF DISTRIBUTABLE INCOME (UNAUDITED)
--------------------------------------------------------------------------------

<Table>
<Caption>
                                          THREE MONTHS ENDED             NINE MONTHS ENDED
                                             SEPTEMBER 30,                 SEPTEMBER 30,
                                      ---------------------------   ---------------------------
                                          2001           2000           2001           2000
<S>                                   <C>            <C>            <C>            <C>
Royalty income ....................   $ 13,971,820   $ 19,747,200   $ 78,047,734   $ 43,432,740
Interest income ...................         13,600         60,985        145,292        102,587
                                      ------------   ------------   ------------   ------------
                                        13,985,420     19,808,185     78,193,026     43,535,327

General and administrative
expenditures ......................        270,489        156,718        964,837        802,537
                                      ------------   ------------   ------------   ------------

Distributable income ..............   $ 13,714,931   $ 19,651,467   $ 77,228,189   $ 42,732,790
                                      ============   ============   ============   ============

Distributable income per Unit
(46,608,796 Units) ................   $    .294255   $    .421626   $   1.656945   $    .916840
                                      ============   ============   ============   ============
</Table>

The accompanying notes to condensed financial statements are an integral part of
these statements.



                                       3
<PAGE>

SAN JUAN BASIN ROYALTY TRUST

CONDENSED STATEMENTS OF CHANGES IN TRUST CORPUS (UNAUDITED)
--------------------------------------------------------------------------------

<Table>
<Caption>
                                                THREE MONTHS ENDED              NINE MONTHS ENDED
                                                   SEPTEMBER 30,                   SEPTEMBER 30,
                                           ----------------------------    ----------------------------
                                               2001            2000            2001            2000
<S>                                        <C>             <C>             <C>             <C>
Trust corpus, beginning of period ......   $ 38,730,055    $ 43,008,647    $ 40,686,854    $ 45,186,199
Amortization of net overriding
royalty interest .......................       (670,988)     (1,349,513)     (2,627,787)     (3,527,065)
Distributable income ...................     13,714,931      19,651,467      77,228,189      42,732,790
Distributions declared .................    (13,714,931)    (19,651,467)    (77,228,189)    (42,732,790)
                                           ------------    ------------    ------------    ------------

Total corpus, end of period ............   $ 38,059,067    $ 41,659,134    $ 38,059,067    $ 41,659,134
                                           ============    ============    ============    ============
</Table>

The accompanying notes to condensed financial statements are an integral part of
these statements.



                                       4
<PAGE>

SAN JUAN BASIN ROYALTY TRUST

NOTES TO CONDENSED FINANCIAL STATEMENTS (UNAUDITED)
--------------------------------------------------------------------------------

1.       BASIS OF ACCOUNTING

         The San Juan Basin Royalty Trust was established as of November 1,
         1980. The financial statements of the Trust are prepared on the
         following basis:

         o        Royalty income recorded for a month is the amount computed and
                  paid by the working interest owner, Burlington Resources Oil &
                  Gas Company LP f/k/a Burlington Resources Oil & Gas Company
                  ("BROG"), to the Trustee for the Trust. Royalty income
                  consists of the amounts received by the owner of the interest
                  burdened by the net overriding royalty interest ("Royalty")
                  from the sale of production less accrued production costs,
                  development and drilling costs, applicable taxes, operating
                  charges, and other costs and deductions, multiplied by 75%.

         o        Trust expenses recorded are based on liabilities paid and cash
                  reserves established from Royalty income for liabilities and
                  contingencies.

         o        Distributions to Unit holders are recorded when declared by
                  the Trustee.

         o        The conveyance which transferred the overriding royalty
                  interest to the Trust provides that any excess of production
                  costs over gross proceeds must be recovered from future net
                  profits.

         The financial statements of the Trust differ from financial statements
         prepared in accordance with accounting principles generally accepted in
         the United States of America ("GAAP") because revenues are not accrued
         in the month of production; certain cash reserves may be established
         for contingencies which would not be accrued in financial statements
         prepared in accordance with GAAP; and amortization of the Royalty
         calculated on a unit-of-production basis is charged directly to trust
         corpus.

2.       FEDERAL INCOME TAXES

         For federal income tax purposes, the Trust constitutes a fixed
         investment trust which is taxed as a grantor trust. A grantor trust is
         not subject to tax at the trust level. The Unit holders are considered
         to own the Trust's income and principal as though no trust were in
         existence. The income of the Trust is deemed to have been received or
         accrued by each Unit holder at the time such income is received or
         accrued by the Trust rather than when distributed by the Trust.

         The Royalty constitutes an "economic interest" in oil and gas
         properties for federal income tax purposes. Unit holders must report
         their share of the revenues of the Trust as ordinary income from oil
         and gas royalties and are entitled to claim depletion with respect to
         such income. The Royalty is treated as a single property for depletion
         purposes.

         The Trust has on file technical advice memoranda confirming the tax
         treatment described above.

         The Trust began receiving royalty income from coal seam gas wells
         beginning in 1989. Under Section 29 of the Internal Revenue Code, coal
         seam gas production from wells drilled prior to



                                       5
<PAGE>

         January 1, 1993 (including certain wells recompleted in coal seam
         formations thereafter), generally qualifies for the federal income tax
         credit for producing non-conventional fuels if such production and the
         sale thereof occurs before January 1, 2003. For 2000, this tax credit
         was $1.06 per MMBtu. The Trust also receives production from wells
         producing from a tight sands formation. These wells must have been
         drilled after November 5, 1990, or must have been committed or
         dedicated to interstate commerce (as defined in Section 2(18) of the
         Natural Gas Policy Act as in effect November 5, 1990) as of April 20,
         1977. This credit is not adjusted for inflation, so the credit remains
         fixed at .517241 per MMBtu. To benefit from the credit, each Unit
         holder must determine from the tax information they receive from the
         Trust, their pro rata share of qualifying production of the Trust,
         based upon the number of Units owned during each month of the year, and
         the amount of available credit per MMBtu for the year, and then apply
         the tax credit against their own income tax liability, but such credit
         may not reduce their regular tax liability (after the foreign tax
         credit and certain other nonrefundable credits) below their alternative
         minimum tax. Section 29 also provides that any amount of Section 29
         credit disallowed for the tax year solely because of this limitation
         will increase their credit for prior year minimum tax liability, which
         may be carried forward indefinitely as a credit against the taxpayer's
         regular tax liability, subject, however, to the limitations described
         in the preceding sentence. There is no provision for the carryback or
         carryforward of the Section 29 credit in any other circumstances.

         The Trustee is provided summary Section 29 tax credit information
         related to Trust properties by BROG, which information is then passed
         along to the Unit holders. In 1999, the U.S. Court of Appeals for the
         10th Circuit upheld the position of the Internal Revenue Service and
         the Tax Court that nonconventional fuel such as coal seam gas does not
         qualify for the Section 29 credit unless the producer has received an
         appropriate well category determination from the Federal Energy
         Regulatory Commission ("FERC"). The FERC's certification authority
         expired effective January 1, 1993. However, on July 14, 2000, the FERC
         issued a final ruling amending its regulations to reinstate certain
         regulations involving well category determinations for all wells and
         tight formation areas that could qualify for the Section 29 tax credit.
         BROG has informed the Trustee that it has identified approximately 250
         wells as non-certified. Of those, BROG has determined that six do not
         qualify for the Section 29 tax credit. BROG has applied to the FERC for
         certification of the approximately 100 qualified wells operated by it,
         and is in communication with the operators of the remaining qualified
         wells to encourage the filing by those operators of applications for
         certification.

         The classification of the Trust's income for purposes of the passive
         loss rules may be important to a Unit holder. As a result of the Tax
         Reform Act of 1986, royalty income will generally be treated as
         portfolio income and will not reduce passive losses.

3.       CONTINGENCIES

         See Part II - Item 1, "Legal Proceedings" concerning the status of
         litigation matters.

4.       UNDERCHARGE OF CAPITAL EXPENDITURES AND LEASE OPERATING EXPENSES

         Based on its 1999 year-end review, BROG determined that it had
         undercharged the Trust for both capital expenditures and lease
         operating charges related to properties burdened by the Trust but not
         operated by BROG. In April and May of 2000, BROG reduced royalty income
         otherwise payable to the Trust by an additional $652,303 in capital
         expenditures and $1,689,509 in lease operating charges related to the
         undercharged non-operated properties. The Trust's consultants have
         reviewed BROG's cost reporting data and confirmed that these additional
         charges were appropriate.



                                       6
<PAGE>

5.       SETTLEMENT OF CLAIMS RELATING TO GAS IMBALANCE

         In June 2000, the Trust and BROG entered into a partial settlement of
         claims relating to a gas imbalance with respect to production from
         mineral properties currently operated by BROG. Under the terms of the
         partial settlement BROG paid the Trust $3,490,000 to settle the
         imbalance insofar as it relates to some of the wells located on the
         subject properties. The remainder of the imbalance is to be addressed
         through volume adjustments whereby the Trust's net overriding royalty
         interest will be applied to 50% of the overproduced parties' interest,
         on a monthly basis, until the imbalance is corrected. The Trust is in
         communication with BROG in order to determine the estimated value of
         the volume adjustments and the time during which the remainder of the
         imbalance will be corrected. Such volume adjustments will be monitored
         by the Trust's consultants.



                                       7
<PAGE>

ITEM 2. TRUSTEE'S DISCUSSION AND ANALYSIS OF FINANCIAL CONDITION AND RESULTS OF
OPERATIONS.

FORWARD-LOOKING INFORMATION.

Certain information included in this report contains, and other materials filed
or to be filed by the Trust with the Securities and Exchange Commission (as well
as information included in oral statements or other written statements made or
to be made by the Trust) may contain or include, forward-looking statements
within the meaning of Section 21E of the Securities Exchange Act of 1934, and
Section 27A of the Securities Act of 1933. Such forward-looking statements may
be or may concern, among other things, capital expenditures, drilling activity,
development activities, production efforts and volumes, hydrocarbon prices and
the results thereof, and regulatory matters. Such forward-looking statements
generally are accompanied by words such as "may," "will," "estimate," "expect,"
"predict," "anticipate," "goal," "should," "assume," "believe," "plan,"
"intend," or other words that convey the uncertainty of future events or
outcomes. Such statements reflect our current view with respect to future
events; are based on our assessment of, and are subject to, a variety of factors
deemed relevant by the Trustee and involve risks and uncertainties. Should one
or more of these risks or uncertainties occur, actual results may vary
materially and adversely from those anticipated.

THREE MONTHS ENDED SEPTEMBER 30, 2001 AND 2000:

The Trust received royalty income of $13,971,820 and interest income of $13,600
during the third quarter of 2001. After deducting administrative expenses of
$270,489, distributable income for the quarter was $13,714,931 ($.294257 per
Unit). In the third quarter of 2000, royalty income was $19,747,200, interest
income was $60,985, administrative expenses were $156,718 and distributable
income was $19,651,467 ($.421626 per Unit). The tax credit relating to
production from coal seam and tight sand wells totaled approximately $.03 per
Unit for the third quarter of 2001 and $.05 per Unit for the third quarter of
2000. For further information concerning this tax credit, Unit holders should
refer to the Trust's Annual Report for 2000. Based on 46,608,796 Units
outstanding, the per Unit distributions during the third quarter of 2001 were as
follows:

<Table>
<S>                              <C>
July .........................   $.116291
August .......................    .109390
September ....................    .068576
                                 --------

Quarter Total ................   $.294257
                                 ========
</Table>

The royalty income distributed in the third quarter of 2001 was lower than that
distributed in the third quarter of 2000, primarily due to a decrease in the
average gas price from $3.39 per Mcf for the third quarter of 2000 to $3.02 per
Mcf for the third quarter of 2001. Interest earnings for the quarter ended
September 30, 2001, as compared to the quarter ended September 30, 2000, were
lower, primarily due to a decrease in funds available for investment and delay
in the receipt of interest earnings. Administrative expenses were higher,
primarily as a result of differences in timing of the receipt and payment of
these expenses.

The capital costs attributable to the properties from which the Trust's 75% net
overriding royalty ("Royalty") was carved (the "Underlying Properties") for the
third quarter of 2001 were reported by BROG as $8,068,949. BROG advised the
Trust that capital expenditures for 2001 are projected to be $30,200,000.
Capital expenditures were $4,994,236 for the third quarter of 2000.
Approximately $25,600,000 in capital expenditures were used in calculating the
Royalty for the year 2000. BROG informed the Trust that its goal in increasing
capital expenditures for 2001 and 2000 was to offset the natural decline in
production from the Underlying Properties. BROG has reported favorable results
in this effort in that natural gas production for the nine months ended
September 2001 averaged approximately 120 MMcf per day, as compared to average



                                       8
<PAGE>

production of approximately 115 MMcf per day for calendar 2000 and approximately
113 MMcf per day for calendar 1999.

BROG has informed the Trust that lease operating expenses and property taxes
were $3,666,991 and $284,063, respectively, for the third quarter of 2001, as
compared to $3,068,852 and $84,317, respectively, for the third quarter of 2000.

BROG has informed the Trustee that during the third quarter of 2001, nine gross
(1.53 net) miscellaneous capital projects, 24 gross (8.32 net) conventional new
wells, 17 gross (4.01 net) payadds, five gross (3.65 net) recompletions and
three gross (2.34 net) restimulations were completed on the Underlying
Properties. Seven gross (.74 net) miscellaneous capital projects, 113 gross
(38.37 net) conventional new wells, 12 gross (7.89 net) payadds, 47 gross (25.64
net) recompletions and eight gross (.68 net) restimulations were in progress at
September 30, 2001. There was one gross (.35 net) coal seam recompletion
completed during the third quarter of 2001. Four (.94 net) coal seam
miscellaneous capital projects, six gross (.21 net) new coal seam wells, and 16
gross (.60 net) coal seam recompletions were in progress at September 30, 2001.
By comparison, twelve gross (8.36 net) conventional wells and one gross (0.003
net) conventional recompletion were completed on the Underlying Properties
during the third quarter of 2000. There were 103 gross (26.24 net) conventional
wells and 32 gross (5.43 net) conventional recompletions in progress at
September 30, 2000. Four gross (2.84 net) coal seam wells and six gross (0.04
net) coal seam recavitations were completed in the third quarter of 2000.
Fourteen gross (4.70 net) coal seam wells, eight gross (0.04 net) coal seam
recavitations and ten gross (1.57 net) coal seam recompletions were in progress
at September 30, 2000.

Royalty income for the quarter ended September 30, 2001 is associated with
actual gas and oil production during May 2001 through July 2001 from the
Underlying Properties. Gas and oil sales from the Underlying Properties for the
quarters ended September 30, 2001 and 2000 were as follows:

<Table>
<Caption>
                                                                                            2001           2000
<S>                                                                                     <C>            <C>
Gas:
   Total sales (Mcf) ................................................................     11,092,019     11,190,629
   Mcf per day ......................................................................        120,565        121,637
   Average price (per Mcf) ..........................................................   $       3.02   $       3.39

Oil:
   Total sales (Bbls) ...............................................................         21,756         27,858
   Bbls per day .....................................................................            236            303
   Average price (per Bbl) ..........................................................   $      23.72   $      25.58

Gas and oil sales attributable to the Royalty for the quarters ended September
30, 2001 and 2000 were as follows:

Gas sales (Mcf) .....................................................................      4,995,406      6,397,659
Oil sales (Bbls) ....................................................................          9,975         15,909
</Table>

Since the oil and gas sales attributable to the Royalty are based on an
allocation formula that is dependent on such factors as price and cost,
including capital expenditures, the aggregate production volumes from the
Underlying Properties may not provide a meaningful comparison to volumes
attributable to the Royalty.

During the third quarter of 2001, gas prices were lower than the prices reported
during the third quarter of 2000. The price per barrel of oil during the third
quarter of 2001 was $1.86 per barrel lower than that received for the third
quarter of 2000 due to decreases in oil prices in world markets generally,
including the posted prices applicable to oil sales attributable to the Royalty.

All volumes of gas which are subject to the Royalty (the "Trust gas") are
currently sold under a contract dated November 10, 1999 between BROG and Duke
Energy and Marketing L.L.C. That contract, as amended, provides for the delivery
of Trust gas at various delivery points over a period commencing January 1,
2000, and ending March 31, 2002, and provides for the sale of Trust gas at
prices which fluctuate in accordance with published indices for gas sold in the
San Juan Basin of New Mexico. Unit holders are



                                       9
<PAGE>

referred to Note 6 of the Notes to Financial Statements in the Trust's 2000
Annual Report for further information concerning the marketing of gas produced
from the Underlying Properties.

In June 2000, the Trust and BROG entered into a partial settlement of claims
relating to a gas imbalance with respect to production from mineral properties
currently operated by BROG. Under the terms of the partial settlement, BROG paid
the Trust $3,490,000 to settle the imbalance insofar as it relates to some of
the wells located on the subject properties. The remainder of the imbalance is
to be addressed through volume adjustments whereby the Trust's net overriding
royalty interest will be applied to 50% of the overproduced parties' interest,
on a monthly basis, until the imbalance is corrected. The Trust is in
communication with BROG in order to determine the estimated value of the volume
adjustments and the time during which the remainder of the imbalance will be
corrected. Such volume adjustments will be monitored by the Trust's
consultants.

NINE MONTHS ENDED SEPTEMBER 30, 2001 AND 2000:

For the nine months ended September 30, 2001, distributable income was
$77,228,189 ($1.656946 per Unit) which was greater than the $42,732,790
($.916840 per Unit) of income distributed during the same period in 2000. The
increase in distributable income resulted primarily from higher gas and oil
prices during the first half of 2001. The royalty income amount of $43,432,740
for the nine months ended September 30, 2000, included $3,490,000 paid to the
Trust as partial settlement of its claims relating to a gas imbalance with
respect to production from mineral properties currently operated by BROG.
Interest income for the nine months ended September 30, 2001 was $145,292
compared to $102,587 during the first nine months of 2000. This increase is due
to the timing of receipt of interest income. General and administrative expenses
were $990,246 compared to $802,537 during the 2000 period primarily due to
differences in timing of the receipt and payment of these expenses.

Capital expenditures incurred by BROG, attributable to the Underlying
Properties, for the first nine months of 2001 amounted to $21,471,867. Capital
expenditures were $14,356,455 for the first nine months of 2000. Lease operating
expenses and property taxes totaled $11,207,821 for the first nine months of
2001 compared to $11,289,538 for the first nine months of 2000.

In April 2000, BROG informed the Trustee that it had determined that since
January of 1999, BROG had undercharged the Trust for both capital expenditures
and lease operating charges related to properties burdened by the Trust's
Royalty but not operated by BROG. In April and May of 2000, BROG passed through
to the Trust additional charges of $652,303 in capital expenditures and
$1,689,509 in lease operating charges related to the undercharged non-operated
properties.

BROG advised the Trustee that during the nine months ended September 30, 2001,
61 gross (23.68 net) conventional wells were completed on the Underlying
Properties, and 16 gross (8.49 net) conventional wells were recompleted. Nine
gross (1.53 net) miscellaneous capital projects, three gross (2.34 net)
restimulations, and 52 gross (6.23 net) conventional payadds were completed.
Four gross (0.27 net) coal seam wells were completed during the first nine
months of 2001. During the nine months ended September 30, 2001, two gross (.76
net) coal seam recompletions, and one gross (.88 net) coal seam payadd were
completed. Six gross (.04 net) coal seam wells were recavitated during the first
nine months of 2001. During the nine months ended September 30, 2000, 26 gross
(14.34 net) conventional wells were completed on the Underlying Properties, and
nine gross (3.693 net) conventional wells were recompleted. Four gross (2.84
net) coal seam wells were completed. Twenty-five gross (0.15 net) coal seam
wells were recavitated and two gross (0.08 net) coal seam wells were
recompleted during the first nine months of 2000.

Royalty income for the nine months ended September 30, 2001 is associated with
actual gas and oil production during November 2000 through July 2001 from the
Underlying Properties. Gas and oil sales from the Underlying Properties for the
nine months ended September 30, 2001 and 2000 were as follows:



                                       10
<PAGE>

<Table>
<Caption>
                                          2001           2000
<S>                                   <C>            <C>
Gas:
   Total sales (Mcf) ..............  $32,711,954       31,933,285
   Mcf per day ....................      119,824          116,545
   Average price (per Mcf) ........  $      4.58     $       2.75

Oil:
   Total Sales (Bbls) .............       71,395           72,925
   Bbls per day ...................          262              266
   Average price (per Bbl) ........  $     25.13     $      23.62
</Table>

Gas and oil sales attributable to the Royalty for the nine months ended
September 30, 2001 and 2000 were as follows:

<Table>
<Caption>
                                          2001           2000
<S>                                   <C>            <C>
Gas sales (Mcf) ...................    17,788,133      15,708,443
Oil sales (Bbls) ..................        39,264          36,486
</Table>

During the first nine months of 2001, gas and oil prices were higher than
during the first nine months of 2000. Since the oil and gas sales attributable
to the Royalty are based on an allocation formula that is dependant on such
factors as price and cost, including capital expenditures, the aggregate sales
amounts from the Underlying Properties may not provide a meaningful comparison
to sales attributable to the Royalty.



                                       11
<PAGE>

CALCULATION OF ROYALTY INCOME:

Royalty income received by the Trust for the three months and nine months ended
September 30, 2001 and 2000, respectively, was computed as shown in the
following table:

<Table>
<Caption>
                                                     THREE MONTHS ENDED              NINE MONTHS ENDED
                                                        SEPTEMBER 30,                   SEPTEMBER 30,
                                                ----------------------------    ----------------------------
                                                    2001            2000            2001            2000
<S>                                             <C>             <C>             <C>             <C>
Gross proceeds of sales from the
Underlying Properties:
Gas proceeds ................................   $ 33,509,718    $ 37,930,505    $149,896,232    $ 85,686,811
Oil proceeds ................................        516,124         712,463       1,794,169       1,721,467
                                                ------------    ------------    ------------    ------------

Total .......................................     34,025,842      38,642,968     151,690,401      87,408,278
                                                ------------    ------------    ------------    ------------

Less production costs:
Severance tax - Gas .........................      3,327,808       4,080,262      14,739,169       8,540,899
Severance tax - Oil .........................         43,939          78,150         162,751         168,572
Severance tax - Other .......................             --              --             148              --
Lease operating expense and property
tax(a) ......................................      3,951,053       3,153,169      11,207,821      11,289,538
Capital expenditures(a) .....................      8,068,949       4,994,236      21,471,867      14,356,455
Other .......................................          5,000           7,551          45,000         129,161
                                                ------------    ------------    ------------    ------------

Total .......................................     15,396,749      12,313,368      47,626,756      34,484,625
                                                ------------    ------------    ------------    ------------

Net profits .................................     18,629,093      26,329,600     104,063,645      52,923,653
Net overriding royalty interest .............             75%             75%             75%             75%
                                                ------------    ------------    ------------    ------------

Subtotal ....................................     13,971,820      19,747,200      78,047,734      39,692,740
Other (b) ...................................             --              --              --       3,740,000
                                                ------------    ------------    ------------    ------------

Royalty income ..............................   $ 13,971,820    $ 19,747,200    $ 78,047,734    $ 43,432,740
                                                ============    ============    ============    ============
</Table>


(a) Includes charges received from BROG during the nine months ended September
30, 2000 for capital expenditures ($652,000) and lease operating costs
($1,690,000) relating to non-operated properties not previously charged to the
Trust (see Note 4 to the financial statements).

(b) Represents additional revenues of $3,490,000 received in the second quarter
of 2000 as settlement of a gas imbalance and a $250,000 offset to lease
operating expense in the first quarter of 2000 in connection with the settlement
of litigation (see Part II - Item 1, "Legal Proceedings.").

ITEM 3. QUANTITATIVE AND QUALITATIVE DISCLOSURES ABOUT MARKET RISK.

The Trust has not entered into derivative financial instruments, derivative
commodity instruments or other similar instruments during the quarter ended
September 30, 2001. The Trust does not market the Trust gas, oil and/or natural
gas liquids. BROG is responsible for such marketing.



                                       12
<PAGE>

                                     PART II
                                OTHER INFORMATION

ITEM 1. LEGAL PROCEEDINGS.

The Trust is not a party to any litigation. However, the Trust is aware that
BROG is involved in litigation from time to time that could affect the royalty
income received by the Trust.

On September 4, 1996, the Trustee announced the settlement of a lawsuit (the
"Litigation") filed by the Trustee against BROG and Southland Royalty Company.
Under the terms of the Settlement Agreement, BROG agreed (i) to pay $19,750,000
in cash plus interest earnings thereon from September 5, 1996, in settlement of
underpayment of royalty claims of the Trust; and (ii) commencing in 1997, to
credit the Trust with $250,000 per year for five years as an offset against
lease operating expenses chargeable to the Trust for purposes of the calculation
of net proceeds payable to the Trust. The Trustee expects that the credit for
2001, the fifth and final payment from BROG under the Settlement Agreement, will
be made in December of 2001. BROG also agreed to make certain adjustments that
represent cost reductions favorable to the Trust in the ongoing charges for coal
seam gas gathering and treating on BROG's Val Verde system. Additionally, the
Trustee and BROG established a formal protocol intended to provide the Trustee
and its representatives improved access to BROG's books and records applicable
to the Underlying Properties. Agreement was also reached regarding marketing
arrangements for the sale of Trust gas, oil and natural gas liquids products
going forward as more particularly described in "Pricing Information" under Item
2. "Properties" of the Trust's report on Form 10-K, filed on March 30, 2001.

The Mineral Management Service of the United States Department of the Interior
(the "MMS") has notified BROG of underpaid royalty related to coal seam gas
including inappropriate deductions for costs to separate carbon dioxide from the
gas. BROG has continued to calculate and pay royalties using deductions the MMS
is attempting to disallow. The Company has appealed the MMS Demand Letter dated
October 28, 1996. There is a tolling agreement with the MMS while settlement
negotiations are attempted.

An administrative claim was initiated on March 17, 1997, by the MMS against BROG
regarding a gas contract settlement dated March 1, 1990, between BROG and
certain other parties thereto (the "1997 MMS Claim"). The claim alleges that
additional royalties are due on production from federal and Indian leases in the
State of New Mexico on properties that are burdened by the Royalty. BROG has
informed the Trust that it has reached an agreement in principle to settle the
1997 MMS claim for $4,078,017.15, of which $2,853,974.15 is allocated to the
production from the Indian lease and of which $1,224,043.00 is allocated to the
production from the federal lease. If this claim is settled on that basis,
royalty income received by the Trust will be reduced by $3,058,512.80. The
Trust's legal advisors and joint interest auditors will review the proposed
reduction in royalty income.

A separate administrative claim was initiated on June 10, 1998, by the MMS
against BROG related to production from lands on the Jicarilla Apache Indian
Reservation (the "1998 MMS Claim"). The claim alleges that additional royalties
are due based upon the "major portion" valuation clause contained in the
Jicarilla leases. This clause contemplated royalty value to be calculated on
"the highest price paid or offered at the time of production for the major
portion of oil of the same gravity, and gas, and/or natural gasoline, and/or all
other hydrocarbon substances produced and sold from the field where the leased
lands are situated." BROG indicates that producers do not have access to prices
received by other producers in a field, so a "major portion" calculation must be
done by the MMS. BROG filed its statement of reasons in June 1999, thereby
contesting whether the royalties are payable as claimed. The 1998 MMS Claim is
in the appeal process. If the 1998 MMS Claim is successful, royalty income
received by the Trust could decrease. However, BROG has informed the Trust that
in connection with the agreement in principle for settlement of the 1997 MMS
Claim, documentation is being drafted to provide for a dollar-for-dollar credit
on the gross



                                       13
<PAGE>

proceeds from gas production ($1,184,600) against any potential liability on the
1998 MMS Claim in an amount equal to the amount paid in settlement of the 1997
MMS Claim.

BROG has successfully negotiated with the State of New Mexico for a tax refund
based upon a claim for reimbursement of compression costs used in calculating
wellhead values. BROG has obtained the approval of the Attorney General of New
Mexico of a settlement in the amount of $4,200,000. In December 2000, the
Royalty payable to the Trust was effectively increased by $263,607 since a
portion of the settlement proceeds in that amount was applied to reduce
production costs used in calculating the Royalty. The Trust's consultants are in
communication with BROG regarding questions which have arisen concerning the
allocation of settlement proceeds.

In June 2000, the Trust and BROG entered into a partial settlement of claims
relating to a gas imbalance with respect to production from mineral properties
currently operated by BROG. Under the terms of the partial settlement BROG paid
the Trust $3,490,000 to settle the imbalance insofar as it relates to some of
the wells located on the subject properties. The remainder of the imbalance is
to be addressed through volume adjustments whereby the Trust's net overriding
royalty interest will be applied to 50% of the overproduced parties' interest,
on a monthly basis, until the imbalance is corrected. The Trust is in
communication with BROG in order to determine the estimated value of the volume
adjustments and the time during which the remainder of the imbalance will be
corrected. BROG has informed the Trust that the volume adjustments were to have
commenced in August 2000. Such volume adjustments will be monitored by the
Trust's consultants.

ITEM 6. EXHIBITS AND REPORTS ON FORM 8-K.

         (a)      Exhibits.

                  (4)(a) San Juan Basin Royalty Trust Indenture dated November
                  3, 1980, between Southland Royalty Company (now Burlington
                  Resources Oil & Gas Company LP) and The Fort Worth National
                  Bank (now Bank One, NA), as Trustee, heretofore filed as
                  Exhibit (4)(a) to the Trust's Annual Report on Form 10-K to
                  the Securities and Exchange Commission for the fiscal year
                  ended December 31, 1980 is incorporated herein by reference.

                  (4)(b) Net Overriding Royalty Conveyance from Southland
                  Royalty Company (now Burlington Resources Oil & Gas Company
                  LP) to The Fort Worth National Bank (now Bank One, NA), as
                  Trustee, dated November 3, 1980 (without Schedules),
                  heretofore filed as Exhibit (4)(b) to the Trust's Annual
                  Report on Form 10-K to the Securities and Exchange Commission
                  for the fiscal year ended December 31, 1980 is incorporated
                  herein by reference.

         (b)      Reports on Form 8-K.

                  No reports on Form 8-K were filed during the quarter ended
                  September 30, 2001.



                                       14
<PAGE>

                                   SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the
Registrant has duly caused this Report to be signed on its behalf by the
undersigned thereunto duly authorized.

                                       BANK ONE, NA, AS TRUSTEE FOR
                                       THE SAN JUAN BASIN ROYALTY TRUST



                                       By /s/ LEE ANN ANDERSON
                                         ---------------------------------------
                                              Lee Ann Anderson
                                              Vice President


Date: November 14, 2001

               (The Trust has no directors or executive officers.)



<PAGE>

                                INDEX TO EXHIBITS



<Table>
<Caption>
                                                                                             SEQUENTIALLY
             EXHIBIT                                                                           NUMBERED
             NUMBER                               EXHIBIT                                        PAGE
             -------                              -------                                    ------------
<S>                                  <C>                                                     <C>
             (4)(a)                  San Juan Basin Royalty Trust Indenture
                                     dated November 3, 1980, between Southland
                                     Royalty Company (now Burlington Resources
                                     Oil & Gas Company LP) and The Fort Worth
                                     National Bank (now Bank One, NA), as
                                     Trustee, heretofore filed as Exhibit (4)(a)
                                     to the Trust's Annual Report on Form 10-K
                                     to the Securities and Exchange Commission
                                     for the fiscal year ended December 31, 1980
                                     is incorporated herein by reference.*

             (4)(b)                  Net Overriding Royalty Conveyance from
                                     Southland Royalty Company (now Burlington
                                     Resources Oil & Gas Company LP) to The Fort
                                     Worth National Bank (now Bank One, NA), as
                                     Trustee, dated November 3, 1980 (without
                                     Schedules), heretofore filed as Exhibit
                                     (4)(b) to the Trust's Annual Report on Form
                                     10-K to the Securities and Exchange
                                     Commission for the fiscal year ended
                                     December 31, 1980 is incorporated herein by
                                     reference.*
</Table>


*    A copy of this Exhibit is available to any Unit holder, at the actual cost
     of reproduction, upon written request to the Trustee, Bank One, NA, P.O.
     2604, Fort Worth, Texas 76113.