Method for explosive expansion toward horizontal free faces for forming an in situ oil shale retort
Formation is excavated from within a retort site in formation containing oil shale for forming a plurality of vertically spaced apart voids extending horizontally across different levels of the retort site, leaving a separate zone of unfragmented formation between each pair of adjacent voids. Explosive is placed in each zone, and such explosive is detonated in a single round for forming an in situ retort containing a fragmented permeable mass of formation particles containing oil shale. The same amount of formation is explosively expanded upwardly and downwardly toward each void. A horizontal void excavated at a production level has a smaller horizontal cross-sectional area than a void excavated at a lower level of the retort site immediately above the production level void. Explosive in a first group of vertical blast holes is detonated for explosively expanding formation downwardly toward the lower void, and explosive in a second group of vertical blast holes is detonated in the same round for explosively expanding formation upwardly toward the lower void and downwardly toward the production level void for forming a generally T-shaped bottom of the fragmented mass.
- Research Organization:
- Occidental Oil Shale, Inc., Grand Junction, CO (United States)
- Sponsoring Organization:
- USDOE
- DOE Contract Number:
- FC20-78LC10036
- Assignee:
- Occidental Oil Shale, Inc. (Grand Junction, CO)
- Patent Number(s):
- 4,192,554
- Application Number:
- 05/929250
- OSTI ID:
- 863523
- Country of Publication:
- United States
- Language:
- English
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