Interface Conductivity and its Correlation with Pore Space Properties

Electrical properties are one of the most important properties in geoscientific fields. They give not only information about porosity but also about interface conductivity and furthermore about specific internal surface. The basic ideas were laid by Archie with his equations for the correlation of electrical resistivity of a saturated rock sample and the resistivity of the fluid. A more detailed investigation with water of different salinity results in the observation of interface conductivity, which is correlated not only to pore space parameters like permeability and porosity but also to specific internal surface. Measurements with increasing salinity of the water were carried out on different samples (sandstone, carbonate, vulcanite/basalt and mudstone). Resulting true formation factor and interfacial conductivity were correlated with other petrophysical properties, like the permeability and porosity. A new parameter which represents the pore geometric properties and lithologic influences.