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Textural controls on low-frequency electrical spectra of porous media

  • The results from several laboratory studies of the relationships between electrical polarization and physical properties of porous media have prompted interest in the potential use of low-frequency electrical spectra to qualitatively or quantitatively map variation in hydrogeologic properties in the field. Compiling several published and unpublished data sets, supported by new measurements, we have examined the low-frequency electrical spectra of a range of natural and artificial porous media to assess the generality of proposed relationships between electrical and physical properties. Our work confirms a significant positive correlation between the magnitude of electrical polarization (quantified as imaginary conductivity at a specific frequency) and the surface-area/pore-volume ratio Spor. Analyzing the parameters of ageneralized Cole-Cole resistivity relaxation model fitted to many electrical spectra, we observe two apparent controls on the electrical relaxation. For samples withThe results from several laboratory studies of the relationships between electrical polarization and physical properties of porous media have prompted interest in the potential use of low-frequency electrical spectra to qualitatively or quantitatively map variation in hydrogeologic properties in the field. Compiling several published and unpublished data sets, supported by new measurements, we have examined the low-frequency electrical spectra of a range of natural and artificial porous media to assess the generality of proposed relationships between electrical and physical properties. Our work confirms a significant positive correlation between the magnitude of electrical polarization (quantified as imaginary conductivity at a specific frequency) and the surface-area/pore-volume ratio Spor. Analyzing the parameters of ageneralized Cole-Cole resistivity relaxation model fitted to many electrical spectra, we observe two apparent controls on the electrical relaxation. For samples with abundant relatively large pore throats, we observe a distinct increase in the time constant of the model with modal pore-throat size, in accordance with classical electrical relaxation models. However, for media with pore structures dominated by small pore throats, the diffusion-length scales do not appear to be controlled by modal pore-throat size. We conclude that for such media, the microstructure of the network of small pores leads to some connectivity of diffusion paths; thus, these samples exhibit relatively large time constants. There is potential value in addition to limitations when using electrical spectra to estimate physical properties of porous media, and we see the need for more appropriate generalized theories of electrical polarization in hydrogeologic media.zeige mehrzeige weniger

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Metadaten
Autor*innen:Sabine KruschwitzORCiD, A. Binley, D. Lesmes, A. Elshenawy
Dokumenttyp:Zeitschriftenartikel
Veröffentlichungsform:Verlagsliteratur
Sprache:Englisch
Titel des übergeordneten Werkes (Englisch):Geophysics
Jahr der Erstveröffentlichung:2010
Verlag:Soc.
Verlagsort:Tulsa, Okla. [u.a.]
Jahrgang/Band:75
Ausgabe/Heft:4
Erste Seite:WA113
Letzte Seite:WA123
Freie Schlagwörter:Diffusion; Geophysical techniques; Sandstone; Saturation; Spectral induced polarization; Temperature; Terrestrial electricity
DOI:10.1190/1.3479835
ISSN:0016-8033
Verfügbarkeit des Dokuments:Physisches Exemplar in der Bibliothek der BAM vorhanden ("Hardcopy Access")
Bibliotheksstandort:Sonderstandort: Publica-Schrank
Datum der Freischaltung:19.02.2016
Referierte Publikation:Ja
Datum der Eintragung als referierte Publikation:20.06.2011
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