1
 
         NOMINEE HOLDER CERTIFICATION AND REQUEST FOR ADDITIONAL RIGHTS
 
To the Subscription Agent:
 
     The undersigned hereby certifies that it is a broker-dealer registered with
the Securities and Exchange Commission, a commercial bank or trust company, a
securities depository or participant therein, or a nominee therefor, holding of
record             shares of Common Stock, par value $.01 per share ("Common
Stock"), of MESA Inc. ("Mesa") on behalf of             beneficial owners as of
the close of business on             , 1996, (the "Record Date") for the
offering by Mesa of an aggregate of approximately 58,407,080 shares of Series A
8% Cumulative Convertible Preferred Stock pursuant to transferable subscription
rights (the "Rights") being distributed to record holders of shares of Common
Stock, all as described in Mesa's Prospectus dated             , 1996 (the
"Prospectus"), a copy of which the undersigned has received. As stated in the
Prospectus, .912 Rights are being distributed for each share of Common Stock
held of record as of the close of business on the Record Date, and any
fractional Right will be rounded up to the nearest whole number. The undersigned
further certifies that             beneficial owners on whose behalf it held, as
of the close of business on the Record Date, an aggregate of             shares
of Common Stock registered in the name of the undersigned are each entitled to
an additional Right in accordance with the policy stated in the Prospectus that
any fractional Right to which a beneficial owner would otherwise be entitled
should be rounded up to the nearest whole number. Accordingly, the undersigned
requests that, upon surrender of its Subscription Certificate evidencing
            Rights, a Subscription Certificate evidencing             Rights
(including             additional Rights in lieu of fractional Rights) be
issued. The undersigned further certifies that each such beneficial owner is a
bona fide beneficial owner of shares of Common Stock, that such beneficial
ownership is reflected on the undersigned's records and that all shares of
Common Stock which, to the undersigned's knowledge, are beneficially owned by
any such beneficial owner through the undersigned have been aggregated in
calculating the foregoing. The undersigned agrees to provide Mesa or its
designee with such additional information as Mesa deems necessary to verify the
foregoing.
 
                                       -----------------------------------------
                                       Name of Record Holder
                               
                                       By:
                                       -----------------------------------------
                                            Name:
                                            Title:
                                            Address:
                                            Telephone Number:
                               
                                    Date:
                                         -------------------------------- , 1996