Empirical characterization of oil shale fragmentation experiments
Shale oil recovery rates that can be achieved in underground in situ retorts can be strongly influenced by the shale breakage and fragment-size distribution achieved during rubblization. Since the fragmentation pattern in the retort is a direct result of the blast design used for rubblization, the characterizing blast parameters should be carefully selected. Explosives should be matched to the host material and blast geometries properly chosen so that the required fragmentation results are achieved at optimum costs. Special attention must be directed to selecting blast parameters that produce uniform bed permeability, suppression of fines, proper fragment size distribution, and minimal damage to the retort walls and ceiling. The influence of joints and natural fractures should also be known. In instances where the requisite blasting parameters are unknown, they should be determined from test blasts. Small and intermediate size cratering and bench blast experiments are being made to determine critical depths, volume crater constants, and fragment-size distribution scaling constants for Piceance Creek Basin oil shale. The small tests are made using PETN explosive in meter-sized blocks. The intermediate-sized tests are on the ten-to-twenty foot scale using an ANFO explosive. The experiments are designed to investigate the adequacy of using empirical scaling laws to describe the influence of bedding plane orientation, burden distance, explosive energy release, and borehole diameter on blast results. Crater volumes, sieved fragment-size distributions, free surface velocities, and explosive detonation velocities are measured. Data are treated using a Livingston type performance evaluation based on explosive volume to determine critical and optimum depths. Measured fragment-size distributions are interpreted using empirical scaling techniques.
- Research Organization:
- Los Alamos Scientific Lab., NM (USA); Rio Blanco Oil Shale Co., Denver, CO (USA)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 6443387
- Report Number(s):
- LA-UR-79-88; CONF-790218-1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
040401* -- Oil Shales & Tar Sands-- In Situ Methods
True & Modified
BITUMINOUS MATERIALS
CARBONACEOUS MATERIALS
COMMINUTION
CRATERING EXPLOSIONS
ENERGY SOURCES
EXPLOSIONS
EXPLOSIVE FRACTURING
EXPLOSIVES
FOSSIL FUELS
FRACTURING
FUELS
GEOLOGIC DEPOSITS
IN-SITU PROCESSING
IN-SITU RETORTING
OIL SHALE DEPOSITS
OIL SHALES
OPTIMIZATION
PICEANCE CREEK BASIN
PROCESSING
RESOURCES
RETORTING