Potential for Producing Oil and Gas from Woodford Shale (Devonian-Mississippian) in the Southern Mid-Continent, USA

COMER, JOHN B., Indiana Geological Survey, Bloomington, IN

Woodford Shale is a prolific oil source rock throughout the southern Mid-Continent of the United States. Extrapolation of thickness and organic geochemical data based on the analysis of 614 samples from the region indicate that on the order of 100 * 10x9 bbl of oil (300 * 10x12 ft(3) of natural gas equivalent) reside in the Woodford in Oklahoma and northwestern Arkansas. The Woodfood in west Texas and southeastern New Mexico contains on the order of 80 * 10x9 bbl of oil (240 * 10(12) ft(3) of natural gas equivalent).

Tapping this resource is most feasible in areas where the Woodford subcrop contains competent lithofacies (e.g., chert, sandstone, siltstone, dolostone) and is high fractured. Horizontal drilling may provide the optimum exploitation technique. Areas with the greatest potential and the most prospective lithologies include (1) the Nemaha uplift (chert, sandstone, dolostone), (2) Marietta-Ardmore basin (chert), (3) southern flank of the Anadarko basin along the Wichita Mountain uplift (chert), (4) frontal zone of the Ouachita tectonic belt in Oklahoma (chert), and (5) the Central Basin platform in west Texas and New Mexico (chert and siltstone).

In virtually all of these areas the Woodford is in the oil or gas window. Thus, fracture porosity would be continuously fed by hydrocarbons generated in the enclosing source rocks. Reservoir systems such as these have typically produced at low to moderate flow rates for many decades.

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)