This project deals with the investigation of complex electrical conductivity by Spectral Induced Polarization (SIP) to get advanced rock characterization of natural solid rocks. Carbonate samples from different locations are available (porosity: 0.5 - 40 %, permeability: 0.001 - 300 mD).
The characteristic properties of these samples are determined by petrophysical measurements (density, porosity, permeability, specific surface, nuclear magnetic resonance (NMR), pore size distribution by mercury porosimetry, x-ray computer tomography), mineralogical (thin section, scanning electron microscope) as well as geochemical analyses. Furthermore, SIP measurements have been carried out with a fluid at constant conductivity (100 mS/m). First results of the SIP measurements show clearly polarization effects and a strong relationship between the real and the imaginary part of the electrical conductivity. The next step will be to derive robust empirical relations between IP and petrophysical parameters. This is followed by extensive experiments to investigate the influence of leaching on the IP spectra. The long-term goal is to understand the (dominating) polarization effects for carbonates in close comparison to the well known mechanism for sandstones.