The Upper Devonian Ohio Shale sequence, including the Cleveland, Three Lock, and upper, middle, and lower Huron, and the Mississippian Berea-Bedford sequence were studied by using XRF and XRD on 14 well samples from the Eastern Kentucky gas field. Elements studied were Mg, Al, Si, P, K, Ca, Ti, Mn, Fe, S, Cu, Zn, Sr, and Na. Minerals studied were chlorite, illite, gypsum, kaolinite, anhydrite, szomolnokite (FeSO₄ × H₂O), quartz, orthoclase, plagioclase, calcite, dolomite, siderite, pyrite, coquimbite (Fe₂(SO₄) × 9H₂O), and secondary quartz.

The data were studied in terms of average values for the total producing sequence, for the Ohio Shale sequence, and for each stratigraphic unit. Computer-drawn maps, using six contour levels, were compared with final open-flow data patterns from a hand-contour map using 4,750 data points and with maps showing density contours of highly productive wells.

A striking pattern match is shown by comparison of several element and mineral maps with the highly productive well density maps. The predictive value of such an investigation is obvious.

Changes of given elements and minerals, within and between wells, were compared across Eastern Kentucky gas field. The pattern relations are not obvious from graphs, nor from the formation density logs of the wells.

Further refinements of this work are in process. To

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date, 72 maps on the elemental analysis have been run and a similar number will be performed on the mineral data.

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