Logging probe for making redox potential measurements

Method and apparatus for electrical logging in a mud-filled borehole by sensing redox potential and other formation characteristics. An elongated, tubular probe body contains reference and potential measuring electrodes which extend longitudinally thereof and are adapted to make external contact wit...

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Bibliographic Details
Main Authors HOWELL; EDDIE P, COFFEE; ROBERT D, HEARN; DANIEL P, GANT, JR.; ORLAND J
Format Patent
LanguageEnglish
Published 09.05.1978
Subjects
DETECTING MASSES OR OBJECTS
GEOPHYSICS
GRAVITATIONAL MEASUREMENTS
MEASURING
PHYSICS
TESTING
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Summary:Method and apparatus for electrical logging in a mud-filled borehole by sensing redox potential and other formation characteristics. An elongated, tubular probe body contains reference and potential measuring electrodes which extend longitudinally thereof and are adapted to make external contact with the borehole fluid at the streamlined surface of the probe nose. The metal reference electrode member is immersed in an electrolyte-filled compartment separated from the external borehole fluid by a pressure-compensating diaphragm in the probe side wall, a fluid bridge with the mud of the borehole being established through a permeable ceramic wick. Probe design insures adequate mud flow past the electrodes in a nonturbulent state as the probe is lowered, thus eliminating clogging and providing good electrical contact. Alternate means are provided for maintaining a positive leak pressure regardless of borehole conditions.
Bibliography:Application Number: US19760753759