Dielectric constant of water in a porous rock medium

Abstract

The dielectric constant of water was measured for solid samples of sandstone in the frequency range from 5 Hz to 13 MHz with different water contents at room temperature. The two electrode technique was employed. The measurements were made on three samples with different cementation: loamy, loamy-carbonate and carbonate. For loamy-carbonate-cemented sandstone, two dielectric relaxation times were observed. The dielectric constant of water was estimated from the data by calculations based on the simple mixing law for partial saturation. The dielectric constant and the dielectric relaxation time of water are functions of water volume in a single pore space. The results are interpreted assuming dipole-dipole interactions, dipole-rock matrix interactions and taking into account Debye's theory.