Pioneer Adds 52MM Barrels of Proved Reserves

Pioneer added proved reserves totaling 52 million barrels oil equivalent (MMBOE) during 2009 from discoveries, extensions and technical revisions. These additions equate to 114% of full-year 2009 production. The drillbit finding and development (F&D) cost for the proved reserve additions was $7.42 per barrel oil equivalent (BOE), a continuing downward trend in the Company’s drillbit F&D cost.

Scott D. Sheffield, Pioneer's Chairman and CEO, stated, "Despite the dramatic curtailment in our 2009 drilling program in response to the commodity price downturn, we were able to grow production, deliver reserve replacement in excess of production and beat our targeted drillbit F&D cost of $10 to $15 per BOE. These significant achievements demonstrate the attractiveness of our large-scale, low-decline assets which require minimal maintenance capital. The significant cost reductions and operational improvements delivered by our employees during the year are also reflected in these strong results."

"The reserve additions were primarily attributable to continued successful drilling in the Kuparuk and Nuiqsut formations at Oooguruk on the North Slope of Alaska, additional discoveries in the Edwards Trend in South Texas, early drilling success in the Eagle Ford Shale in South Texas and a limited drilling program in the Spraberry field in West Texas. We also saw better production and cost performance across our assets, especially in the Spraberry, Edwards Trend and Raton areas."