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U.S. Department of Energy
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Method for forming an in situ oil shale retort with horizontal free faces

Patent ·
OSTI ID:5715213

A method for forming a fragmented permeable mass of formation particles in an in situ oil shale retort is described. A horizontally extending void is excavated in unfragmented formation containing oil shale and a zone of unfragmented formation is left adjacent the void. An array of explosive chrarges is formed in the zone of unfragmented formation. The array of explosive charges comprises rows of central explosive charges surrounded by a band of outer explosive charges which are adjacent side boundaries of the retort being formed. The powder factor of each outer explosive charge is made approx. equal to the powder factor of each central explosive charge. The explosive charges are detonated for explosively expanding the zone of unfragmented formation toward the void for forming the fragmented permeable mass of formation particles having a reasonably uniformly distributed void fraction in the in situ oil shale retort. 41 claims.

Assignee:
Occidental Oil Shale Inc.
Patent Number(s):
US 4366987
OSTI ID:
5715213
Country of Publication:
United States
Language:
English