Dielectric Permittivity Of Clay-Water-Organic Compound: Frequency Dependence

Abstract

Through non-invasive or other geophysical techniques, the ultimate goal of a geophysical survey is the identification of subsurface materials and their spatial distributions. Reaching this goal will only be possible through a complete understanding of the physical properties of different materials. A detailed petrophysical work is essential to gain insight of what kind of changes can be observed through geophysical techniques. In this research, the effects of organic contaminants in a clay-water mixture were investigated via dielectric permittivity under controlled laboratory conditions. For this investigation four organic contaminants, trichloroethylene (TCE), tetrachloroethylene (PCE), ethylene glycol, and phenol, were added to previously prepared samples of clay-water mixtures, and their dielectric permittivities were measured. The dielectric permittivities of contaminated versus uncontaminated samples were compared to determine if there was any pattern to help to identify a particular organic contaminant via dielectric permittivity values of the mixtures. Depending on the nature of the organic material, the changes observed are: 1) A decrease of the magnitude of dielectric permittivity and shift of the relaxation frequency to lower frequencies for ethylene glycol and phenol and, 2) An increase in the magnitude of dielectric permittivity and shift of the relaxation toward higher frequencies for TCE and PCE contaminated samples between 100 KHz and 350 MHz frequencies.