Hydrocarbon Production from the Devonian Shale in Letcher and Knott Counties, Eastern Kentucky

Abstract

ABSTRACT The Kentucky Geological Survey (KGS) at the University of Kentucky is conducting a research project funded by the Gas Research Institute (GRI) to study hydrocarbon production from the Devonian shale in eastern Kentucky. The primary objectives of this project are to develop an understanding of the relationship between local geology and hydrocarbon production from the Devonian shale, to create a comprehensive Devonian shale data base of well information, and to prepare an oil and gas report for each county in the study area. Project data have been compiled from the KGS oil and gas well record files, the GRI Eastern Gas Data System (EGDS), files from the U.S. Department of Energy (DOE), and records from cooperating oil and gas companies operating within the study area. Gamma-ray logs were found to be the most valid means of identifying the stratigraphic units within the Devonian shale. Temperature logs are used to locate gas shows in order to determine which interval to stimulate. The combined use of the temperature log to find the gas shows, and the gamma-ray log to identify which stratigraphic unit the gas is coming from, is an invaluable method for determining the treatment interval. The two most common methods of stimulating production in Letcher and Knott Counties are explosive shooting and hydraulic fracturing. Comparison of the initial potentials both before and after treatment indicates that hydraulic fracturing is preferable to borehole shooting for improving production in the Devonian shale. Data compilation in Letcher and Knott Counties is complete. An extensive data base of information on the 1,412 Devonian shale wells in Letcher and Knott Counties has been compiled. Using this information, detailed stratigraphic cross sections within the Devonian-Mississippian shale sequence have been constructed, as well as structure, isopach, and isopotential maps. Analysis of the maps and cross sections suggest two relationships. There appears to be a direct relationship between areas of high Devonian shale initial open-flow potential and 1) the location of shallower hydrocarbon production, and 2) the location of linear features determined from LANDSAT imagery. The preliminary results of this study provide the petroleum industry with valuable guidelines for the future exploration of natural gas in the Devonian shales of eastern Kentucky.