The Southern Extremity of the "Clinton" Gas Pools in Ohio

Abstract

Published in Petroleum Transactions, AIME, Volume 57, 1917, pages 984–988. The Cleveland (O.) gas pool described by Frank R. Van Horn,' is the northern extremity of the great "Clinton" sand gas development in Ohio. Numerous gas pools have been developed in this formation, which are now more or less connected, link by link, forming an almost continuous gas pool, starting at Cleveland, and running thence southward through Cuyahoga, Medina, Wayne, Ashland, Richland, Knox, Licking, Fairfield, Hocking, and Vinton counties. The present southern extremity of these connected pools is in Richland Township, Vinton County (Fig. 1). The writer offers his analysis of the Richland Township development which may serve to compare the northern and southern extremities. Geology The geologist is greatly handicapped by the lack of a suitable key- horizon, inasmuch as the outcropping rocks are members of the "Big Injun" series of the Logan Group (Mississippian). The underlying shales (Waverly shales) show that considerable erosion took place before the deposition of the "Big Injun," which accounts for the presence of an erosion plane between these two formations, further complicating the study of the geological structure from surface outcrops. A reliable structural map of the "Clinton" is obtainable only by spirit-level elevations at the mouth of the various wells drilled, and the elevation of the sand calculated from the logs of the wells. The accompanying isobath map has been prepared in this manner (Fig. 2). Since the completion of this map, numerous wells have been drilled in the town- ship, which, if taken into consideration, might cause a slight variation in the appearance of the contour lines. The monotonous monoclinal structure of the "Clinton" sand is evident from this map. The thickness of the Berea is variable from place to place without any regularity; but in the other formations cited, the smaller measurements are met with in the western part of the township, the thickening taking place toward the east (Fig. 3). The Berea lies at an elevation of about 250 ft. above sea level at the western line, and is close to sea level at the eastern line of the township. The average dip for the Berea is about 35 ft. per mile. This compares with an average dip of 80 ft. per mile for the "Clinton" in the same territory. The difference in dip is due to the lateral variation of the intervening strata. T.P. 057–48