Formation strength parameters from acoustic and density logs in emplacement holes

Conference · Tue Jan 01 04:00:00 EST 1991

OSTI ID:5009223

Mathews, M A; Fenster, R A; Plannerer, H N

A new acoustic tool for dry emplacement holes has been built and tested in several emplacement holes. This tool uses a large hammer source and 3 piezo-electric transducers that are independently pressed against the borehole wall. The detectors are 6, 9 and 12 ft from the hammer source. A pure gel is injected between these detectors and the borehole wall to eliminate any air space. The compressional wave travel time and the shear wave travel time are recorded at each detector. The compressional wave velocity (V{sub p}) and the shear wave velocity (V{sub s}) are calculated from the travel time differences between the 3 detectors and their separations of 3 and 6 ft. These velocity values along with the bulk density obtained from the density log are used to calculate the Elastic Constants of Young's Modules, Bulk Modules, Shear Modules and Poisson's Ratio. These elastic moduli compared favorably to some core derived elastic moduli obtained from emplacement hole U19ba. These mechanical rock properties are presently used in phenomenological analysis and seismic verification assessment. The V{sub p} velocities obtained from the acoustic logs in U19ba and U3mt compared reasonably well with the geophone survey velocities from these emplacement holes. The only major differences occurred in the fracture intervals of I19ba where the fracture intervals were identified with the borehole camera. The geophone velocities were much less than the acoustic velocities in these fractured intervals. 7 refs., 25 figs.

• Research Organization: Los Alamos National Lab., NM (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: W-7405-ENG-36
• OSTI ID: 5009223
• Report Number(s): LA-UR-91-2682; CONF-9108135--4; ON: DE91018022
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580000* -- Geosciences
ACOUSTIC MEASUREMENTS
BOREHOLES
CAVITIES
DENSITY
GEOLOGIC FRACTURES
GEOLOGIC STRUCTURES
GEOPHYSICS
MEASURING METHODS
MECHANICAL PROPERTIES
PHYSICAL PROPERTIES
POISSON RATIO
SHEAR
TRANSDUCERS
VELOCITY
WAVE PROPAGATION
YOUNG MODULUS