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Relation of in situ resistivity to water content in salt rocks 1
Author(s) -
Yaramanci U.
Publication year - 1994
Publication title -
geophysical prospecting
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.735
H-Index - 79
eISSN - 1365-2478
pISSN - 0016-8025
DOI - 10.1111/j.1365-2478.1994.tb00207.x
Subject(s) - electrical resistivity and conductivity , geology , borehole , mineralogy , water content , cementation (geology) , igneous petrology , porosity , gemology , pore water pressure , saturation (graph theory) , geotechnical engineering , engineering geology , materials science , cement , composite material , volcanism , seismology , electrical engineering , engineering , tectonics , mathematics , combinatorics
The investigation of water in salt‐rock formations is of particular relevance to underground nuclear waste repositories. In the Asse salt‐mine (Germany) a study into the relationship of in situ resistivity to water content has been made. Measurements were carried out in older rock‐salt using an electrode array in boreholes, an electrode profile in a drift and small resistivity sensors in and around a drift seal. Further measurements were made on moist zones in a contact area of younger rock‐salt and carnallitite and also in older rock‐salt with anhydrite bands using electrode profiles in the drifts. The resistivities range from 10 2 Ωm to 10 6 Ωm. Corresponding probes have water contents from 0.01% to 1.3%. A definite relationship between resistivity and water content is revealed which can be described by Archie's law using a cementation factor m of 1.9. Porosities are between 0.08% and 1.4% and the saturations vary considerably. An explicit influence of saturation on resistivity cannot be discovered using the present data. The results enable us to estimate the in situ water content and the order of the in situ porosity using resistivity surveys at different scales. This increases significantly the safety of a nuclear repository site.