Pioneer Makes Fifth Discovery on Jenein Nord Block

Pioneer Natural Resources made its fifth discovery on its operated Jenein Nord Block (50% interest assuming ETAP participation) in Tunisia. Based on wire-line logs and down-hole sampling, the latest discovery well, Farrah, will be perforated and tested in three intervals totaling 20 meters. Testing is expected to begin in late August.

Pioneer has now drilled five consecutive successful exploration wells on the Jenein Nord Block and plans to drill three more exploration wells on the block by year-end. The Company also plans to acquire additional 3-D seismic data to evaluate the potential of another portion of the block, which is adjacent to the area containing the five successful wells. Three exploration wells on adjacent non-operated blocks are also planned by year-end.

Plans to construct oil production facilities on the Jenein Nord Block are progressing, and first production from the block is anticipated late in the fourth quarter of 2007. During 2007, Pioneer's average net daily production from Tunisia is expected to rise more than 80% to at least 5,400 barrels of oil per day (BOPD). For 2008, the Company's average net daily production is expected to rise more than 90% to greater than 10,000 BOPD.

Immediately north of the Jenein Nord Block, Pioneer is acquiring an additional 15% interest in the 1.2 million acre Anaguid Block from an affiliate of Anadarko Petroleum Company which will bring Pioneer's total interest to 60% (subject to the right of ETAP, the state oil company, to assume 50% of such interest). The transaction is subject to certain conditions, including government consent, and is expected to close within 60 to 90 days. As part of the transaction, Pioneer becomes operator of the Anaguid Block. Following government approval, Pioneer intends to acquire 3-D data over the portion of the Anaguid Block that adjoins the Jenein Nord and Adam blocks and expects to drill an Anaguid exploration well in 2008.

"We are pleased with the continued success of our efforts to expand our new core area in Tunisia and anticipate significant production and reserve growth from the strong foundation we've established," stated Scott Sheffield, Pioneer's Chairman and CEO.