Quantitative Measurements of Streaming Potential and High–frequency Seismoelectric Conversion in Berea Sandstone Sample

Abstract

Streaming potential across a porous medium is induced by a fluid flow due to an electric double layer. When an acoustic wave propagates through a porous medium, the wave pressure generates a relative movement between the solid and the fluid. The moving charge in the fluid induces an electric field due to the seismoelectric conversion. To investigate the streaming potential and the seismoelectric conversion in the same rock sample, we conduct quantitative measurements with cylindrical and plate samples of Berea sandstone 500 saturated by NaCl solutions with different conductivities. We measure the electric voltage (streaming potential) across a cylinder sample in NaCl solutions and under different pressures. In a solution container, we measure the seismoelectric signals induced by acoustic waves at different frequencies and solution conductivities. The pressures of the acoustic waves are quantitatively calibrated at different frequencies. We calculate the quantitative coupling coefficients of the seismoelectric conversion at DC and high frequencies with samples saturated by solutions with different conductivities. According to the streaming potentials, we calculate the theoretical coupling coefficients at the DC and the high frequency range with Pride’s equations. The experimental and theoretical results are compared quantitatively and their differences are discussed.