The seismoelectric effect: A nonisochoric streaming current: 2. Theory and its experimental verification

Propagation of ultrasound waves through a porous body saturated with liquid generates an electric response. This electroacoustic effect is called the “seismoelectric current”; the reverse phenomenon, where an electric field is the driving force, is known as the “electroseismic current”. The seismoelectric current can be measured with existing electroacoustic devices that were originally designed to characterize liquid dispersions. The versatility of electroacoustic devices allows them to be calibrated using dispersions and then applied to the characterization of porous bodies. Here, we present the theory of the seismoelectric effect, which we derived by following the path suggested 65 years ago by Frenkel. To verify this theory, we measured the seismoelectric current generated by sediments of micrometer-sized silica particles. We demonstrated that the measurement allowed the determination of porosity of the sediment and the calculation of the ζ-potential. The ζ-potential value, calculated using the suggested theory, closely agreed with the value independently measured for moderately concentrated dispersions using a well-known electroacoustic theory for dispersions. Measurements of the seismoelectric effect with existing electroacoustic probes open up new ways for characterizing the porosity and ζ-potential of porous bodies, including ones with low permeability.

Propagation of ultrasound through a porous body saturated with liquid generates an electric response, which is called “seismoelectric current.” It can be described as “streaming current” under nonisochoric conditions when compressibility becomes important. Seismoelectric currents can be measured with electroacoustic devices originally designed for characterizing liquid dispersions. This effect can be used for characterizing ζ-potential, porosity, and pore size of porous bodies.Figure optionsDownload high-quality image (68 K)Download as PowerPoint slide