Using electrical resistance tomography to map subsurface temperatures

Patent · Sat Jan 01 00:00:00 EST 1994

OSTI ID:869486

Ramirez, Abelardo L ^[1]; Chesnut, Dwayne A ^[2]; Daily, William D ^[3]

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1. Pleasanton, CA
2. San Francisco, CA
3. Livermore, CA

A method is provided for measuring subsurface soil or rock temperatures remotely using electrical resistivity tomography (ERT). Electrical resistivity measurements are made using electrodes implanted in boreholes driven into the soil and/or at the ground surface. The measurements are repeated as some process changes the temperatures of the soil mass/rock mass. Tomographs of electrical resistivity are calculated based on the measurements using Poisson's equation. Changes in the soil/rock resistivity can be related to changes in soil/rock temperatures when: (1) the electrical conductivity of the fluid trapped in the soil's pore space is low, (2) the soil/rock has a high cation exchange capacity and (3) the temperature changes are sufficiently high. When these three conditions exist the resistivity changes observed in the ERT tomographs can be directly attributed to changes in soil/rock temperatures. This method provides a way of mapping temperature changes in subsurface soils remotely. Distances over which the ERT method can be used to monitor changes in soil temperature range from tens to hundreds of meters from the electrode locations.

• Research Organization: Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
• DOE Contract Number: W-7405-ENG-48
• Assignee: Regents of University of California (Oakland, CA)
• Patent Number(s): US 5346307
• OSTI ID: 869486
• Country of Publication: United States
• Language: English

Related Subjects

electrical
resistance
tomography
map
subsurface
temperatures
method
provided
measuring
soil
rock
remotely
resistivity
measurements
electrodes
implanted
boreholes
driven
ground
surface
repeated
process
changes
mass
tomographs
calculated
based
poisson
equation
related
conductivity
fluid
trapped
pore
space
cation
exchange
capacity
temperature
sufficiently
conditions
exist
observed
directly
attributed
provides
mapping
soils
distances
monitor
range
tens
hundreds
meters
electrode
locations
temperature change
temperature changes
cation exchange
temperature range
electrical resistance
electrical conductivity
electrical resistivity
method provides
ground surface
surface temperature
method provide
resistance tomography
resistivity measurements
subsurface soil
process changes
rock mass
surface temperatures
calculated based
resistivity changes
resistivity change
soil mass
measuring subsurface
map subsurface
temperatures remotely
exchange capacity
surface soils
/374/324/