ELECTRICAL-PROPERTIES OF OILSHALE ROCKS

The characterization of electric properties of oilshale deposit is reported. The scanning electron microscopy and the results of the dielectric constants show that the deposit is a heterogeneous composite material containing some conducting and insulating microstructural units. The components of the equivalent input impedance measured at microwave frequencies (8 to 12 GHz) and the impedance at low frequencies (0.5 Hz to 30 kHz) showed frequency dependence. The real and imaginary components of the permittivity determined from the impedance data obtained at low frequencies showed an exponential decreased with frequency. The observed frequency dependence of the rock permittivity is ascribed generally to a Maxwell-Wagner type of mechanism. Also it was observed that the conductivity is almost independent of the frequency below 1 kHz and increase with frequency above this range. The values obtained for the conductivity at low frequencies indicate that the rock has an inter-mediate electrical conduction due to some mineralized metallic complexes and carbon content.