Abstract

The Pembrook 587 well is located in the SW ¼, of Section 4, Block D, Northeast Upton County in the axial position of the Midland Basin of West Texas. Pioneer Natural Resources drilled this well in 2007 to a total depth of f 8,122 ft MD and obtained approximately 123 ft of core. The core targeted the principal conventional reservoirs of the Spraberry Formation. The upper 63 feet of core was obtained over the upper Spraberry 1U interval (depths of 6,968 ft to 7,031 ft MD). The upper Spraberry 1U core section displays fine-grained siltstone to shaley-siltstone units, depositional facies include: thin bedded turbidites, eolian-silt and pelagic shale varve sequences, and hemipelagic shales. 1U porosities range between 0.1-13.7%, permeability range of 0.001-0.541 mD, and Soc between 4.7-13.3%. The lower section of core was obtained in the lower Spraberry over the Jo Mill interval (depths of 7,865 -7,925ft). Jo Mill porosities range between 11.0-13.7%, permeability range of 0.001-1.43 mD, and Soc between 4.7-13.3%. This section of core consists of fine-grained siltstone to shaley-siltstone units. Historically, Spraberry production has focused on the fine grain sheet-like turbidite facies located in the 1U, 5U and Jo Mill intervals. These reservoir intervals are separated vertically from each other at this location by interbedded siltstone and shale (not cored).