Pioneer Boosts Production Growth by 10% in 4Q 2010

Pioneer has added proved reserves totaling 104 million barrels oil equivalent (MMBOE) during 2010 from discoveries, extensions, improved recovery, purchases of minerals-in-place and technical revisions related to performance improvements. These additions equate to replacing 232% of Pioneer's full-year 2010 production of 45 MMBOE (including reserves used for field fuel of 3 MMBOE). The drillbit finding and development (F&D) cost related to proved reserve additions was $9.96 per barrel oil equivalent (BOE).

Pioneer also added proved reserves totaling 59 MMBOE during 2010 as a result of positive price revisions. The prices used for 2010 reserves reporting purposes were $79.28 per barrel for oil and $4.37 per million British thermal units (MMBtu) for gas compared to $61.14 per barrel of oil and $3.87 per MMBtu of gas used to calculate proved reserves for 2009. The positive pricing revisions primarily reflect the addition of proved reserves in the Spraberry field due to the higher prices extending the economic life of the field's producing wells and the addition of proved undeveloped reserves (PUDs) that became economic with the increase in gas prices in the Raton field.

Pioneer's proved reserve additions from the drillbit, acquisitions and revisions totaled 163 MMBOE for full-year 2010. This equates to replacing 363% of full-year 2010 production and results in an all-in F&D cost for the proved reserve additions of $7.30 per BOE. After taking into account the Company's total production for 2010 of 45 MMBOE and divestitures of 6 MMBOE (mostly related to Pioneer's joint venture with Reliance Industries), proved oil and gas reserves totaled 1,011 MMBOE as of December 31, 2010, up 112 MMBOE, or 12%, from year-end 2009.

Scott D. Sheffield, Chairman and CEO, stated, "In 2010, we were able to achieve our production growth target of 10% from the fourth quarter of 2009 to the fourth quarter of 2010, deliver reserve replacement well in excess of production and were below our targeted drillbit F&D cost of $10 to $15 per BOE for the year. This strong performance is in large part due to the successful execution of our plan to significantly ramp up drilling in the Spraberry field and the Eagle Ford Shale. It also reflects our continued successful drilling on the North Slope of Alaska and the drilling program in Tunisia prior to the recently announced sale of this asset.”

Approximately 97% of Pioneer's proved reserves are in the United States and 57% are proved developed (PD). Approximately 56% of proved reserves are oil and natural gas liquids (NGLs), and 44% are gas. Pioneer's proved reserves are long-lived with a total reserves-to-production ratio of approximately 22 years and a PD reserves-to-production ratio of 13 years.