THE MARCELLUS SHALE: EROSIONAL BOUNDARY AND PRODUCTION ANALYSIS, SOUTHERN WEST VIRGINIA, U.S.A.

Abstract

The Middle Devonian Marcellus Shale is a natural gas producing formation that was deposited in the Appalachian foreland basin in what is now eastern North America. An unconformity truncates the Marcellus in southern West Virginia and progressively younger units onlap progressively older units. The zero isopach line that marks the edge of the Marcellus is mapped to reveal the southeastern boundary. A well production analysis is conducted to locate the region of maximum natural gas production. Four lithologic completions intervals in three different well fields are compared. This study shows that the most economically viable drilling is from the Marcellus Shale completion intervals that are less than 30 feet in Chapmanville gas field in western Logan County, West Virginia. Outside of the zero isopach are areas comprised of onlapping featheredges of younger formations that comprise a black shale unit mistakenly identified as “Marcellus Shale.” These areas produce significantly less gas than the “true” Marcellus Shale.