Method of attenuating airblast from detonating explosive in an in situ oil shale retort
An in situ oil shale retort is formed in a subterranean formation containing oil shale and including underground workings by excavating a means for access to a retort site in the formation, excavating a void in the retort site at least in part from the means for access, leaving a remaining portion of the unfragmented formation in the retort site adjacent the void, placing explosive in the remaining portion of formation, and detonating the explosive in such unfragmented formation in a single round to explosively expand formation toward the void for forming a fragmented permeable mass of formation particles containing oil shale in an in situ retort. A permeable barrier is provided between the void and the underground workings which provide means for access to such a void. The permeable barrier has a cross-section for gas flow which is substantially smaller than the transverse cross-section of such means for access, and the cross-section of such permeable barrier temporarily confines gas from such explosive expansion and limits flow of such gas to such means for access to attentuate airblast in underground workings. A fragmented permeable mass of formation particles produced during excavation of the void can provide such a permeable barrier.
- Assignee:
- Occidental Oil Shale Inc
- Patent Number(s):
- US 4239285
- Application Number:
- TRN: 81-008168
- OSTI ID:
- 6482392
- Resource Relation:
- Patent File Date: Filed date 20 Jun 1979
- Country of Publication:
- United States
- Language:
- English
Similar Records
Mining system for in situ oil shale retorts
Method for explosively expanding a pillar
Related Subjects
45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE
IN-SITU RETORTING
UNDERGROUND EXPLOSIONS
OIL SHALE DEPOSITS
EXPLOSIVE FRACTURING
OIL SHALES
GAS FLOW
VOIDS
BITUMINOUS MATERIALS
CARBONACEOUS MATERIALS
CHEMICAL REACTIONS
COMMINUTION
DECOMPOSITION
ENERGY SOURCES
EXPLOSIONS
FLUID FLOW
FOSSIL FUELS
FRACTURING
FUELS
GEOLOGIC DEPOSITS
IN-SITU PROCESSING
MATERIALS
MINERAL RESOURCES
PROCESSING
RESOURCES
RETORTING
040401* - Oil Shales & Tar Sands- In Situ Methods
True & Modified
450100 - Military Technology
Weaponry
& National Defense- Chemical Explosions & Explosives
040300 - Oil Shales & Tar Sands- Drilling
Fracturing & Mining