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U.S. Department of Energy
Office of Scientific and Technical Information

Staggered array of explosives for fragmented oil shale formation toward a vertical free face

Patent ·
OSTI ID:6206788

Oil shale formation is explosively expanded toward a limited void volume for forming an in situ oil shale retort in a subterranean formation containing oil shale. In one embodiment, a void in the form of a vertical slot is excavated within a retort site, leaving at least one portion of unfragmented formation within the retort site adjacent a vertical free face of the slot. Explosive is placed in at least 2 rows of vertical blasting holes in the remaining portion of unfragmented formation adjacent the vertical free face. The blasting holes in each row are mutually spaced apart along the length of the slot and longitudinally offset from blasting holes in the next adjacent row, and the row of blasting holes extends generally parallel to the vertical free face. Explosive in the blasting holes is detonated in a time delay sequence starting near one end of the slot and progressing along the length of the slot for explosively expanding formation in the remaining portion of unfragmented formation toward the vertical free face for forming a fragmented permeable mass of formation particles containing oil shale in an in situ oil shale retort. 31 claims.

Assignee:
Occidental Oil Shale Inc.
Patent Number(s):
US 4194789
OSTI ID:
6206788
Country of Publication:
United States
Language:
English