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Title: Methods and apparatus for measurement of the resistivity of geological formations from within cased boreholes

Abstract

Methods and apparatus are disclosed which allow measurement of the resistivity of a geological formation through borehole casing which may be surrounded by brine saturated cement. A.C. current is passed from an electrode in electrical contact with the interior of the borehole casing to an electrode on the surface of the earth. The A.C. voltage difference is measured between two additional vertically disposed electrodes on the interior of the casing which provides a measure of the resistivity of the geological formation. A calibration and nulling procedure is presented which minimizes the influence of variations in the thickness of the casing. The procedure also minimizes the influence of inaccurate placements of the additional vertically disposed electrodes. 3 figs.

Inventors:
Issue Date:
OSTI Identifier:
7164630
Patent Number(s):
4820989
Application Number:
PPN: US 6-927115
Assignee:
ParaMagnetic Logging, Inc., Woodinville, WA (United States)
DOE Contract Number:  
FG06-84ER13294
Resource Type:
Patent
Resource Relation:
Patent File Date: 4 Nov 1986
Country of Publication:
United States
Language:
English
Subject:
47 OTHER INSTRUMENTATION; RESISTIVITY LOGGING; WELL LOGGING EQUIPMENT; DESIGN; OPERATION; BOREHOLES; CALIBRATION; ELECTRIC CONDUCTIVITY; RESERVOIR ROCK; WELL CASINGS; CAVITIES; ELECTRIC LOGGING; ELECTRICAL PROPERTIES; EQUIPMENT; PHYSICAL PROPERTIES; WELL LOGGING; 440400* - Well Logging Instrumentation

Citation Formats

Vail, III, W B. Methods and apparatus for measurement of the resistivity of geological formations from within cased boreholes. United States: N. p., 1989. Web.
Vail, III, W B. Methods and apparatus for measurement of the resistivity of geological formations from within cased boreholes. United States.
Vail, III, W B. Tue . "Methods and apparatus for measurement of the resistivity of geological formations from within cased boreholes". United States.
@article{osti_7164630,
title = {Methods and apparatus for measurement of the resistivity of geological formations from within cased boreholes},
author = {Vail, III, W B},
abstractNote = {Methods and apparatus are disclosed which allow measurement of the resistivity of a geological formation through borehole casing which may be surrounded by brine saturated cement. A.C. current is passed from an electrode in electrical contact with the interior of the borehole casing to an electrode on the surface of the earth. The A.C. voltage difference is measured between two additional vertically disposed electrodes on the interior of the casing which provides a measure of the resistivity of the geological formation. A calibration and nulling procedure is presented which minimizes the influence of variations in the thickness of the casing. The procedure also minimizes the influence of inaccurate placements of the additional vertically disposed electrodes. 3 figs.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1989},
month = {4}
}