Shear wave transducer for stress measurements in boreholes

Patent · Thu Jan 01 00:00:00 EST 1987

OSTI ID:866134

Mao, Nai-Hsien ^[1]

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1. Castro Valley, CA

A technique and apparatus for estimating in situ stresses by measuring stress-induced velocity anisotropy around a borehole. Two sets each of radially and tangentially polarized transducers are placed inside the hole with displacement directions either parallel or perpendicular to the principal stress directions. With this configuration, relative travel times are measured by both a pulsed phase-locked loop technique and a cross correlation of digitized waveforms. The biaxial velocity data is used to back-calculate the applied stress.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• DOE Contract Number: W-7405-ENG-48
• Assignee: United States of America as represented by United States (Washington, DC)
• Patent Number(s): US 4641520
• OSTI ID: 866134
• Country of Publication: United States
• Language: English

Related Subjects

shear
wave
transducer
stress
measurements
boreholes
technique
apparatus
estimating
situ
stresses
measuring
stress-induced
velocity
anisotropy
borehole
sets
radially
tangentially
polarized
transducers
placed
inside
displacement
directions
parallel
perpendicular
principal
configuration
relative
travel
times
measured
pulsed
phase-locked
loop
correlation
digitized
waveforms
biaxial
data
back-calculate
applied
shear wave
placed inside
travel time
stress measurements
phase-locked loop
measuring stress
wave transducer
velocity anisotropy
/73/367/