Pioneer Natural Resources Co.(Pioneer) and Pioneer Southwest Energy Partners LP (Pioneer Southwest) have struck an agreement for their previously announced merger under which Pioneer Southwest would become a wholly owned subsidiary of Pioneer operating company Pioneer Natural Resources USA Inc. (see Shale Daily, May 13). The transaction is intended to consolidate the West Texas Midland Basin activities of the two companies and facilitate Pioneer’s plans to fully and optimally develop the area utilizing horizontal drilling. The combination is expected to provide organizational, operational and administrative efficiencies, Pioneer said. Pioneer Southwest’s public unitholders are to receive 0.2325 of a share of common stock of Pioneer per Pioneer Southwest common unit surrendered, plus a whole share of Pioneer common stock in lieu of any fractional share of Pioneer common stock otherwise issuable in the merger. The transaction is expected to result in 3.95 million additional shares of common stock being issued by Pioneer.