Experimental determination of frequency- and temperature-dependent electrical properties of water-saturated clays using spectral induced polarization and network analyzer technique

International audienceImpedance and vector network analyzer measurements are combined in order to measure frequency dependent conductivity and permittivity of two different saturated clays: montmorillonite and illite chlorite. In the low frequency range, the complex conductivity is determined over the 10 mHz to 45 kHz frequency range using a complex impedance analyzer with a 4-electrodes cell. In the high frequency range (50 MHz to 5 GHz), the complex permittivity is obtained from measured reflection factor of an open-ended probe. The ultrabroadband constitutive properties of the saturated clays were investigated in the temperature range 25 • C down to 0 • C. A mixture equation, based on a volume average approach, was applied to model the low and high frequency electrical properties based on the formation factor. The temperature dependency was considered in the following petrophysical quantities: low frequency conductivity, chargeability and high frequency permittivity. The modeled results are in reasonable agreement with measurements