Explosively produced fracture of oil shale

Explosive cratering experiments were conducted as a part of the research effort to study the explosively produced fracture of oil shale. They were designed to identify and analyze the major factors involved in the fracturing of oil shale, to provide data for the verification of the computer models, and ultimately to lead to the design of a rubble bed for in situ retorting oil shale. The rubble excavated from eight cratering experiments was separated and the volumes of rubble in each screened size category are presented. Also presented are the data from the detailed investigation of the joint/fracture attitudes (strikes and dips) within a crater interior after excavation. The data were tabulated and plotted to allow future comparisons and analyses pertinent to similar experiments. A brief discussion of the experiment site and the graphical representation of the data are included. Finally, since the homogeneity of the oil shale is an important consideration in the selection of a site for these explosive fracture experiments, cores were taken and analyzed. The identification of the geological parameters and their extent and how they delineate the overall characterization of the experiment site, including the subsurface geology, is given. It is shown how the postshot core analysis will indicate how the blast affected the rock.