Exhibit 99.1

           Mission Resources Issues Mid-Year Reserve Update

    HOUSTON--(BUSINESS WIRE)--July 29, 2004--Mission Resources
Corporation (Nasdaq:MSSN) announced today that in connection with the
previously announced review of strategic alternatives, Mission has
directed Netherland, Sewell and Associates Inc., the Company's
independent reservoir engineering firm, to prepare a report on the
Company's reserves as of July 1, 2004. The Company's proved reserves
per this report are 217 billion cubic feet of gas equivalent ("Bcfe").
This figure compares with Dec. 31, 2003 reported proved reserves of
178 Bcfe and announced year-end reserves pro forma for the Jalmat
Acquisition of 209 Bcfe.
    "We are pleased that additions to our reserve base have
significantly outpaced production in the first half of the year," said
Robert L. Cavnar, chairman, president and chief executive officer.
"These increased proved reserve figures are the result of focused
efforts by our team to identify and develop opportunities and to
high-grade our asset base."
    The proved reserves are approximately 63% natural gas/natural gas
liquids and 77% developed. The approximate regional breakdown of
proved reserves is as follows: 65% Permian Basin, 24% Gulf Coast
Onshore, and 11% Gulf of Mexico and other. The proved reserve to
production ratio is approximately 9 years. Currently, the Company's
net production is approximately 71 million cubic feet equivalent per
day.
    About Mission Resources: Mission Resources Corporation is a
Houston-based independent exploration and production company that
drills for, acquires, develops and produces natural gas and crude oil
primarily in the Permian Basin (in West Texas and Southeastern New
Mexico), along the Texas and Louisiana Gulf Coast and in both the
state and federal waters of the Gulf of Mexico.
    This press release contains "forward-looking statements" within
the meaning of Section 27A of the Securities Act of 1933, as amended,
and Section 21E of the Securities Exchange Act of 1934, as amended.
These forward-looking statements are subject to certain risks, trends
and uncertainties that could cause actual results to differ materially
from those projected. Among those risks, trends and uncertainties are
our estimate of the sufficiency of our existing capital sources, our
ability to raise additional capital to fund cash requirements for
future operations, the uncertainties involved in estimating quantities
of proved oil and natural gas reserves, in prospect development and
property acquisitions and in projecting future rates of production,
the timing of development expenditures and drilling of wells, and the
operating hazards attendant to the oil and gas business. In
particular, careful consideration should be given to cautionary
statements made in the various reports the Company has filed with the
Securities and Exchange Commission. Mission undertakes no duty to
update or revise these forward-looking statements.

    CONTACT: Mission Resources Corporation, Houston
             Ann Kaesermann, 713-495-3100
             investors@mrcorp.com
             www.mrcorp.com