Relation between electric properties and water saturation for hematitic sandstone with frequency

Autor: M. M. Gomaa
Jazyk: angličtina
Rok vydání: 2008
Předmět:
Zdroj: Annals of Geophysics, Vol 51, Iss 5-6, Pp 801-811 (2008)
Druh dokumentu: article
ISSN: 1593-5213
2037-416X
DOI: 10.4401/ag-3015
Popis: This paper focuses on the effect of water saturation on A. C. electrical conductivity and dielectric constant of fully and partially saturated hematitic sandstone sample (Aswan area, Egypt). The saturation of the sample was changed from partial to full saturation. Complex resistivity measurements at room temperature (~16°C), were performed in the frequency range from 0.1 Hz to 100 KHz. Experimental electrical spectra indicate, generally, that the electrical conductivity and dielectric constant vary strongly with water saturations and frequency. The low frequency electrical conductivity and dielectric constant are mainly controlled by surface conduction and polarization of the electrical double layer. The behaviour of the electrical conductivity and dielectric constant, with increasing water content, were argued to the orientational polarization of bound water for very low saturations, displacement of the excess surface charges for relatively low saturations, and free exchange of excess ions in double layer with the bulk electrolyte and generation of transient diffusion potentials which lag behind the applied field for high saturations.
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