Devonian Shale Gas Production, Photolineaments, and Geology in Central Appalachian Basin of West Virginia: ABSTRACT

Abstract

Remote-sensing methods involving photolineament mapping have been used for hydrocarbon prospecting with varying success. Much natural gas in the Appalachian basin is in formations of very low primary permeability; therefore production is from fractures. Natural fracture zones often appear as photolineaments on various types of remote-sensing images. In some parts of the basin, photolineaments have been demonstrated to be loci of improved production of natural gas. Photolineaments are also often indicative of surface and subsurface fractures and stress fields. A test was made of these relations for Devonian shale gas production in the central part of the Appalachian basin. Photolineaments were derived from satellite and aircraft images at a scale of 1:250,000; fracture dat were measured on surface outcrops and in one core; and natural gas production data were open flows as given on drillers' logs. Fractures generally parallel nearby photolineaments, but the relation is not simple. Natural open flows tend to be lower on or near photolineaments than between them, whereas open flows of stimulated wells do not appear to be related to photolineaments. Such relations may be due to venting of gas through natural fractures, and the stimulated wells, having new fractures, release previously trapped gas. The disparity between results from this project and those of others may be due to several factors: the allochthonous sedimentary sheets present in the area of some other projects do not extend into the central part of the Appalachian basin; the lithologies differ i significant ways; and the methods used for mapping and the types of photolineaments differ. End_of_Article - Last_Page 847------------