Saturation and contamination dependence of electrical properties in the MHz range

The application of electrical and electromagnetic measurements on geotechnical and environmental problems requires detailed knowledge of the influence of lithology, pore structure and pore filling on the electrical properties of rocks. Former investigations at frequencies up to 1 MHz (Kulenkampff, 1994) have shown that frequency dependent electrical measurements yield especially information about parameters describing the pore structure due to polarization effects caused by electrochemical reactions at the internal surface. Only for highly porous media, pore filling considerably affects the complex conductivity spectra. This is one reason for the strong deviations between the results of measurements and mixing formulas like complex reflection index method (CRIM) or Bruggernann-Hanai-Sen-Shen (BHSS) which ignore surface effects (Urban, 1995). The aim of the presented work is to examine the influence of saturation and contamination of samples of different lithology and known pore structure on the electrical properties in the Mhz range to provide a data base for the interpretation of electromagnetic field measurements. Furthermore, the investigations should result in a quantification of the relation between electrical parameters and pore structure controlling the hydraulic and diffusive transport of pore fluids.