We present in this paper the results of measurements of the complex dielectric permittivity and electric conductivity in three different porous media, made from unconsolidated acid-purified quartz sand and glass grains. To ensure the generality of the results, we use sand and glass grains of different geometry and particle size distribution. The measurements are made in the frequency range of 300kHz-3GHz, which covers the operating frequencies of all electromagnetic tools.

We have made measurements in a specially designed capillary pressure cell with a built-in transmission line which goes through the porous media. The measured capillary pressure curves serve as an indication of the capillary hysteresis during the entire drainage and imbibition cycle. From the scattering characteristics of the built-in transmission line, we computed the complex dielectric permittivity of the porous media as function of frequency and water saturation.

We obtained different values of complex dielectric permittivity and electric conductivity at the same water saturation during drainage and imbibition. At water saturation lower than approx. 0.6 the values of permittivity for the imbibition is lower than those for the drainage. At higher water saturation, the picture is the other way around.

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