Tectonic Controls on the Devonian Shale-Gas Plays Along the Pine Mountain Thrust Fault System

Abstract

There is an increasing demand for hydrocarbon exploration within the Eastern Kentucky Appalachian Basin along the Pine Mountain Thrust Fault System. The number of new gas wells in this area has increased dramatically, and the production of natural gas in Kentucky has doubled from 2008 to 2009. This research focuses on the tectonic influences on the lateral variation of the Devonian Shale along the Pine Mountain Thrust Fault. The goal of this study is to investigate the tectonic and structural controls on fracturing (“fracking”) and maturity of the Devonian Shale to understand its potentiality both as a source and reservoir rock. Various methods were used including thin section petrography, GIS mapping and core sample analysis. Thin sections were used to determine deformation, and the density and intensity of natural fractures within the shale; GIS maps were generated to determine if any correlation exists between the number of wells, well depth, and various study locations along the fault. The initial results of our ongoing study show that structural deformation of shearing and subsequent up-thrust have led to tight hinge-zones of the footwall. The overriding thrust sheet has undergone extensional deformation to a lesser degree. This tectonic activity has resulted in open tension and closed compression fractures. These structures combined with secondary fractures and regional trends have allowed natural fracture patterns to develop within the lower and the upper members of the Devonian Shale. It is postulated that core samples will show that joints and fractures of the upper shale will generally follow the same structural pattern as the overlying units but that the lower shale will see greater deformation and a higher degree of fracture development. This study suggests that hydraulic stimulation of this complex and highly fractured unit could invoke significant recovery.

AAPG Datapages/Search and Discovery Article #90216 ©2015 AAPG Annual Convention and Exhibition, Denver, CO., May 31 - June 3, 2015