Selected shale characterization exploration parameters defined from Eastern Gas Shales Project investigations to identify highly potential Devonian shale exploration areas were used by Tetra Tech, Inc., to select drilling sites in the Appalachian, Michigan, and Illinois basins. The characterization parameters used for site selection were: (1) thickness of the shales, (2) type of organic matter, (3) percent of organic carbon, (4) thermal maturation, and (5) the presence of secondary natural-fracture porosity. The fracture analysis investigation over eastern Ohio using remote sensing techniques describes a method which should prove useful for locating secondary natural-fracture porosity reservoirs in regions of horizontal or slightly dipping strata.

Detailed field checks over a pilot area in Hocking County, Ohio, indicated that approximately 50% of mapped photo linears were not fracture related. A hypothetical interpretive technique developed to identify only the fracture-related photo linears was used in interpreting and mapping fractures over the entire area of eastern Ohio.

Statistical analysis of this data was necessary due to the large volume of data. A computer program was developed that analytically distinguished the regional and local components of the data. Computer-generated first and second-degree and corresponding residual maps showed areas of eastern Ohio where fracture density exceeded or was less than the regional norm.

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High-density fracture areas, located within high-potential exploration areas (as defined by the other four exploration parameters), should have high potential for Devonian shale or "Clinton" sandstone natural gas production.

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