UNITED STATES
               SECURITIES AND EXCHANGE COMMISSION

                    Washington, D.C.  20549


                          SCHEDULE 13D


           Under the Securities Exchange Act of 1934

        Southwest Developmental Drilling Fund 91-A, L.P.
                        (Name of Issuer)


                 Limited Partnership Interests
                 (Title of Class of Securities)


                         Not Applicable
                         (CUSIP Number)








                    CUSIP No. Not Applicable

 (1) Names of Reporting Persons              Southwest Royalties,
Inc.
     S.S. or I.R.S. Identification           75-1917432
     Nos. of Above Persons

 (2) Check the Appropriate Box               (a)
     if a Member of a Group                  (b)  X

 (3) SEC Use Only

 (4) Source of Funds                         WC

 (5) Check if Disclosure of Legal
     Proceedings is Required
     Pursuant to Items 2(d) or 2(e)               Not Applicable

 (6) Citizenship or Place of
     Organization                            Delaware corporation


Number  of  Shares/Units  Beneficially Owned  by  Each  Reporting
Person With:


 (7) Sole Voting Power                       72.0 Units

 (8) Share Voting Power                      None

 (9) Sole Dispositive Power                  72.0 Units

(10) Shared Dispositive Power                None

(11) Aggregate Amount Beneficially
     Owned by Each Reporting Person               72.0 Units

(12) Check if the Aggregate Amount
     in Row (11) Excludes Certain
     Shares                                  Not Applicable

(13) Percent of Class Represented
     by Amount in Row (11)                   6.3% of class of
                                        1,144.5 Units

(14)                                         Type   of  Reporting
                                             Person
                                             CO (Managing General
                                             Partner of Issuer)



Item 1.                                 Type     of     Security:
                                        Limited       Partnership
                                        Interests ("Units")

                                             Name of Issuer:
                                        Southwest Developmental
                                        Drilling Fund 91-A, L.P.

          Address of Issuer's           407 N. Big Spring St.
          Principal Executive           Suite 300
           Offices:                       Midland, Texas   79701-
4326

Item 2(a).     Name of Person
          Filing:                       Southwest Royalties, Inc.

Item  2(b).      Address of Principal                407  N.  Big
Spring St.
            Business  Office:                    Midland,   Texas
79701-4326

Item 2(c).     Present Occupation:           Not Applicable

Item 2(d).     Criminal Convictions:              None

Item 2(e).     Civil Securities Laws
          Injunctions or
          Prohibitions:                 None

Item   2(f).       Citizenship:                         Delaware,
U.S.A.

Item 3.                                 Source      of     Funds:
                                        Working  capital  of  the
                                        Reporting Person.

Item 4.   Purpose of Transactions:

     Satisfied requirements of the Right of Presentment contained
     in the Issuer's Agreement of Limited Partnership whereby the
     Reporting  Person,  as Managing General Partner,  agrees  to
     acquire Units from limited partners seeking an exit from the
     Issuer at a formula price.


Item 5.        Interest in Securities

     The  Reporting Person, which is the Issuer: Managing General
     Partner  of  the  Issuer, holds a total  of  72.0  Units  of
     limited partnership interests over which it has sole  voting
     and  dispositive powers.  These Units represent 6.3% of  the
     total  1,144.5 Units which are issued and outstanding.   The
     purchase transactions which resulted in the ownership of the
     Reporting  Person exceeding 5% occurred between February  1,
     1997  and  June 30, 2003 when the Reporting Person purchased
     an  additional  50  Units as part of the Issuer's  Right  of
     Presentment program.  The price per unit was $135.68.

Item 6.   Contracts, Arrangements,
          Undertakings or Relationships
          with Respect to Securities of
          the Issuer:                             Not Applicable

Item 7.   Material to Be Filed as
          Exhibits:                          Not Applicable



                           SIGNATURE


     After reasonable inquiry and to the best of my knowledge and
belief,  I  certify  that  the  information  set  forth  in  this
statement is true, complete and correct.





Date: July 8, 2003                                By:   /s/  Bill
                                        E. Coggin

- -------------------------
                                        --------
                                   Bill E. Coggin, Executive
                                   Vice-President and CFO,
                                   of Southwest Royalties,
                                     Inc.  the  Managing  General
Partner