Electroseismic Investigation Of The Shallow Subsurface: Field Measurements And Numerical Modeling

Abstract

Electroseismic phenomena in porous media, first observed almost 60 years ago (Ivanov, 1939), were recently "rediscovered" due to their potential to detect zones of high fluid mobility and fluid chemistry contrasts in the subsurface (Thompson and Gist, 1993; Haartsen et al., 1995). However, a limited number of field studies of these phenomena reported in the literature were not able to support the results with an explicit comparison to theoretical predictions. In this paper, we demonstrate that electroseismic phenomena in porous media can be observed in the field, explained, and modeled numerically, yielding a good agreement between the field and the synthetic data. We first outline the design of our field experiment and describe the procedure used to reduce noise in the electroseismic data. Then, we present and interpret the field data, demonstrating how and where different electroseismic signals originated in the subsurface. Finally, we model our field experiment numerically and demonstrate that the numerical results correctly simulate arrival times, polarity, and the amplitude-versus-offset behavior of the electroseismic signals measured in the field.