Pioneer Begins Sidetrack Operations on Harrier Field

Pioneer Natural Resources has shut in production from the Harrier field in the Falcon Corridor of the deepwater Gulf of Mexico as a result of early water encroachment. A sidetrack well is expected to spud in mid-September to access an adjacent fault block in the field and could be producing by the end of October. Proved reserves for the Falcon Corridor are not expected to change significantly as any impact to Harrier reserves should be offset by reserve additions related to better than expected production data for the Falcon field.

Pioneer plans to initiate a drilling campaign in the Falcon Corridor during the first half of 2005 that is expected to include two to three exploration wells and another sidetrack targeting additional reserves.

Pioneer expects total company production for the third quarter to average 180,000 to 185,000 barrels oil equivalent per day, reflecting the impact of downtime for the above mentioned Harrier operations and weather-related downtime on the Canyon Express and Devils Tower systems stemming from personnel evacuations for hurricanes Charlie and Earl. The new third quarter production range does not include allowances for any additional downtime related to weather.