METHOD OF FORMING IN SITU OIL SHALE RETORTS

摘要

89-OS-77 BE IT KNOWN THAT GORDON B. FRENCH a citizen of the United States of America of 7684- North Quartz Street, Golden, Colorado 80401, United States of America, having made an invention entitled: METHOD OF FORMING IN SITU OIL SHALE RETORTS the following disclosure contains a correct and full description of the invention and of the best mode known to the inventor(s) of taking advantage of the same. A row of horizontally spaced apart in situ oil shale retorts is formed in a subterranean formation containing oil shale. Each row is formed by excavating at least a pair of upper and lower retort access drifts at elevations within the top and bottom boundaries of the retort sites. The access drifts extend through opposite side boundaries of a plurality of retorts in such row. Each retort is formed by excavating upper and lower horizontal voids at the levels of the upper and lower retort access drifts, respectively, such voids being excavated laterally from the access drift within the side boundaries of the retort sites. Each retort is formed by explosively expanding formation toward the upper and lower voids within the boundaries of the retort site to form a fragmented permeable mass of particles containing oil shale in each retort. Following formation of each retort, the retort access drifts on the advancing side of the retort are at least partially sealed, preferably with a mass of formation particles covered by a gas impermeable layer and backfilled with a further mass of formation particles.