Gas Resource Potential of the Woodford Shale, Arkoma Basin, Oklahoma
Devon Energy Corporation, Oklahoma City, OK
The Woodford Shale (Lower Mississippian-Upper Devonian) has emerged as one of the most significant resource plays to develop in Oklahoma. The play area encompasses more than 1200 square miles, and lies within a 4 county area in eastern to southeastern Oklahoma. The play is defined to the west by the gas maturity level, and to east by the regional complexity of the Choctaw Thrust System. The Woodford Shale, as it is regionally termed, is an organic-rich mudstone by definition, consisting of predominantly silica and illite, with minor amounts of pyrite, and dolomite. The Woodford formation throughout the mid-continent is considered a world-class source rock, as it has provided the hydrocarbon source and seal for numerous major stratigraphic and structural conventional reservoir traps. Through outcrop, core and petrophysical measurements, the TOC values can exceed 15%, illustrating its potential as a hydrocarbon source. The emergence and refinement of the Barnett Shale play in the Fort Worth Basin of North central Texas lead Devon Energy to apply its drilling and completion experience to this resource shale candidate. Initial vertical drilling began in May of 2004, with vertical completion activities showing mixed to poor results. Devon's initial horizontal well was spud in January of 2005 with an initial production rate of 3000 MCFD. Development continued with the current completed well count at 31, with five rigs drilling in the focus area of Coal and Hughes counties, Oklahoma.
AAPG Search and Discovery Article #90071 © 2007 AAPG Rocky Mountain Meeting, Snowbird, Utah