Hole-to-surface resistivity measurements at Salt Valley, Utah

Open-File Report 80-981
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Abstract

Evaporites are an important potential medium for the storage of radioactive wastes. In order to ascertain the viability of a proposed waste isolation site, it is necessary to study its geology without extensive drilling that might destroy its structural integrity. Hole-to-surface and hole-to-hole geophysical measurements can be useful in supplementing geologic data obtained from a few drill holes and can be used to aid the interpretation of surface geophysical measurements. The study presented in this paper was conducted at Salt Valley, Utah to test the feasibility of using hole-to-surface direct-current resistivity measurements to detect geologic inhomogeneities in evaporites. These measurements show the following:
(1) It is feasible to make hole-to-surface resistivity measurements over evaporites. However, near-surface steel casing can make it difficult to quantitatively analyze the field data with present interpretation techniques. Future investigations should include theoretical studies to solve interpretation problems when steel casing is in the hole and the mud is a high-conductivity brine.
(2) A comparison of measurements made from the three different source drill holes shows that the halite acts as an electrical insulator and most of the current emitted from the source is contained in the caprock.
(3) A comparison of measurements made parallel and perpendicular to the valley walls shows that there are more variations in the halitecaprock        interface perpendicular than parallel to the axis of the Salt Valley anticline.
(4) Structurally complex interbeds within the salt may cause differences in the current distribution measured at the surface from current sources buried at different depths.
(5) Total field mapping would be more useful than the single-component data that were collected in this study.

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Publication type Report
Publication Subtype USGS Numbered Series
Title Hole-to-surface resistivity measurements at Salt Valley, Utah
Series title Open-File Report
Series number 80-981
DOI 10.3133/ofr80981
Year Published 1980
Language English
Publisher U.S. Geological Survey
Description 35 p.
Country United States
State Utah
Other Geospatial Salt Valley
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