Pioneer Natural Resource's Eagle Ford Shale reserves grew to 70 million barrels at the end of 2011. Pioneer's core assets cut through the condensate rich window of the Eagle Ford in DeWitt, Karnes, and Live Oak counties. For the entire company, Pioneer added 149 mmboe of proved reserves, which replaced 313% of the company's 49 mmboe of production in 2011. Management attributed the strong performance to the Sprayberry field (West Texas), the Barnett Combo (North of Fort Worth), and the South Texas Eagle Ford. 

The Eagle Ford accounts for less than 10% of Pioneer's proved reserves, but that will change dramatically in the next few years as the company is able to prove reserves from land not yet drilled.