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Title: Using electrical resistance tomography to map subsurface temperatures

Abstract

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. 1 fig.

Inventors:
; ;
Issue Date:
OSTI Identifier:
6974583
Patent Number(s):
5346307 A
Application Number:
PPN: US 8-072601
Assignee:
Univ. of California, Oakland, CA (United States) PTO; EDB-94-155648
DOE Contract Number:  
W-7405-ENG-48
Resource Type:
Patent
Resource Relation:
Patent File Date: 3 Jun 1993
Country of Publication:
United States
Language:
English
Subject:
58 GEOSCIENCES; 54 ENVIRONMENTAL SCIENCES; RESERVOIR ROCK; ELECTRIC CONDUCTIVITY; TEMPERATURE MONITORING; SOILS; TOMOGRAPHY; PERFORMANCE; RESERVOIR TEMPERATURE; WELL LOGGING EQUIPMENT; DIAGNOSTIC TECHNIQUES; ELECTRICAL PROPERTIES; EQUIPMENT; MONITORING; PHYSICAL PROPERTIES; 580000* - Geosciences; 540250 - Environment, Terrestrial- Site Resource & Use Studies- (1990-)

Citation Formats

Ramirez, A.L., Chesnut, D.A., and Daily, W.D. Using electrical resistance tomography to map subsurface temperatures. United States: N. p., 1994. Web.
Ramirez, A.L., Chesnut, D.A., & Daily, W.D. Using electrical resistance tomography to map subsurface temperatures. United States.
Ramirez, A.L., Chesnut, D.A., and Daily, W.D. Tue . "Using electrical resistance tomography to map subsurface temperatures". United States.
@article{osti_6974583,
title = {Using electrical resistance tomography to map subsurface temperatures},
author = {Ramirez, A.L. and Chesnut, D.A. and Daily, W.D.},
abstractNote = {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. 1 fig.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1994},
month = {9}
}