Over 1 Tcf of high-quality natural gas has been produced from Devonian shales during the past 100 years. The shale is its own source, seal, and reservoir; natural features within the shale form the reservoir. Organic shale is the prime requisite for production, but productivity relates to the presence of open fractures so that one can presume that abnormally productive trends correspond to open fracture zones. This presumption is supported by the direct association of linear zones of high production with linear basement structure detailed in three fields studied. The blanketlike nature of the lower production ubiquitous in southern West Virginia and eastern Kentucky probably relates to a fracture facies developed within the shale and controlled by shale lithology and Appa achian tectonics.

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