Three-component borehole wall-locking seismic detector

Patent · Fri Dec 31 23:00:00 EST 1993

OSTI ID:869235

Owen, Thomas E ^[1]

---

1. Helotes, TX

A seismic detector for boreholes is described that has an accelerometer sensor block for sensing vibrations in geologic formations of the earth. The density of the seismic detector is approximately matched to the density of the formations in which the detector is utilized. A simple compass is used to orient the seismic detector. A large surface area shoe having a radius approximately equal to the radius of the borehole in which the seismic detector is located may be pushed against the side of the borehole by actuating cylinders contained in the seismic detector. Hydraulic drive of the cylinders is provided external to the detector. By using the large surface area wall-locking shoe, force holding the seismic detector in place is distributed over a larger area of the borehole wall thereby eliminating concentrated stresses. Borehole wall-locking forces up to ten times the weight of the seismic detector can be applied thereby ensuring maximum detection frequency response up to 2,000 hertz using accelerometer sensors in a triaxial array within the seismic detector.

• Research Organization: SOUTHWEST RESEARCH INSTITUTE
• DOE Contract Number: AC22-89BC14473
• Assignee: Southwest Research Institute (San Antonio, TX)
• Patent Number(s): US 5302782
• OSTI ID: 869235
• Country of Publication: United States
• Language: English

Related Subjects

/181/
000
accelerometer
actuating
applied
approximately
approximately equal
array
axial array
block
borehole
borehole wall
boreholes
compass
concentrated
contained
cylinders
density
described
detection
detector
distributed
drive
earth
eliminating
ensuring
equal
external
force
forces
formations
frequency
frequency response
geologic
geologic formations
hertz
holding
hydraulic
hydraulic drive
larger
located
matched
maximum
orient
provided
pushed
radius
response
seismic
seismic detector
sensing
sensing vibrations
sensor
sensor block
sensors
shoe
simple
stresses
surface
three-component
times
triaxial
utilized
vibrations
wall
wall-locking
weight