Tuesday 13 November 2012, AmsterdamThe Spraberry field is the largest oil field in the Lower 48 states of the US, and Pioneer holds nearly 900,000 gross acres in this field. The field is the company’s key asset and contributed 36.1% towards its production and 57.3% towards its proved reserves in 2011. Its reserves in the Spraberry field are expected to consist of 90% oil, with the remainder as natural gas. The development of the field is expected to boost Pioneer’s oil production in the future. Increasing oil production in a scenario of high oil prices compared to natural gas prices will support the company’s profitability, thereby increasing its cash flows in the future. Pioneer plans to focus on supplementing its production growth from the Spraberry field through the development of the upper and lower Spraberry formation, the Dean formation and the horizontal Wolfcamp formation.