Pioneer Makes Deepwater Discovery on Clipper Prospect

Pioneer Natural Resources has made a discovery on its Clipper prospect in the Green Canyon 299 Block in the deepwater Gulf of Mexico. Pioneer operates the block with a 55% working interest. The block is included in Pioneer's deepwater Gulf of Mexico divestment program which includes existing production from Canyon Express, Devils Tower and the Falcon Corridor, discoveries under development at Ozona Deep and Thunder Hawk, and ninety exploration blocks.

Pioneer plans to open the divestment data room during the week of October 17. The Company is being advised by Randall & Dewey on its deepwater Gulf of Mexico sale and the sale is expected to close around year end 2005.

In June, Pioneer announced that after completing the Clipper well, it planned to drill the subsalt Paladin prospect in the Garden Banks area of the deepwater Gulf of Mexico. As a result of delays caused by Hurricanes Katrina and Rita and the planned divestiture of its deepwater Gulf of Mexico assets, the Company is requesting a suspension of operations extension with the Minerals Management Service and deferring drilling this well.