Chapter 4 - Multifrequency conductivity and permittivity of porous material containing conductive particles in redox inactive conditions

Abstract

Chapter 4 describes the development of a mechanistic model of multifrequency conductivity and permittivity for a homogeneous porous media containing uniformly distributed conductive particles (e.g. pyrite). This model is referred as the PPIP model that is combined with the SCAIP model from Chapter 3. The mixtures under investigation are assumed to be saturated with hydrocarbon and brine/water. The chapter focuses on the interfacial polarization effects of both conductive and non-conductive minerals on the effective conductivity in the frequency range of 100 Hz to 100 kHz and on the effective permittivity in the frequency range of 0.5 MHz–1 GHz. The presence of conductive particles increases the effective permittivity and decreases the effective conductivity at lower frequencies. Effective conductivity reduces and effective permittivity increases for mixtures containing conductive particles of smaller characteristic lengths. The low-frequency dispersion can hardly be observed for electrolyte with conductivity value higher than 1 S/m. Moreover, the conductive particles dominate the prediction of effective permittivity for frequencies below 5 MHz, especially when the conductivity of the electrolyte is high. In the frequency windows mentioned above, the frequency dispersion of complex conductivity because of the IFP effects for clays are negligible compared to conductive particles.