In a new series of experiments now being conducted by the U.S. Bureau of Mines, directional control of the combustion zone in underground gasification of coal requires detailed knowledge of the geology of the test site. In particular, directional properties of the coal and rocks above and below must be known accurately in order to control the advance of the combustion zone and the movement of product gases. To obtain the information necessary to select a site for conducting these experiments, a series of surface and subsurface studies was planned.

Specifically, remote-sensing imagery and photography were examined over northern West Virginia where the coalbeds are buried deepest. From these, lineaments and fracture traces were mapped to determine the location of gas-venting zones. Structural features such as anticlines, synclines, and joint strikes also were mapped and remote sensing lineaments were field checked during the surface geologic studies. Surveys to establish bench marks for subsidence measurements were conducted. In the subsurface analysis, oriented cores of rocks above and below the coalbed were obtained and directional properties such as tensile strength, permeability, preferred-failure direction, and joint strike measurements were made.

Correlation of oriented core data with surface geologic studies was used to determine the direction for deviation of the long horizontal injection and production wells to be drilled for the coal gasification experiment. These studies showed that delineation of directional characteristics of the rock strata is essential for siting and planning any in situ extraction process.

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