Laboratory Experiment on 2D Inversion of ERT Data with Different Borehole Arrangements

Abstract

This paper discusses the effects of the three types of electrode arrangements on inversion resolution of electrical resistivity tomography (ERT). Through the lab flume (1.2m long and 0.85 deep) experiment and a high-resistivity rock (approximately 1000Ωm) under the low-resistivity salt water (approximately 3Ωm) background, this paper carries out inversion with cross-hole, borehole-to-surface and surface-to-borehole arrays. The inverted maps from the cross-hole and borehole-to-surface data cannot perform the target well but it can roughly delineate the boundary between the high-resistivity and low-resistivity layers. The inversion resolution of the surface-to-borehole data is the worst of the three types. However, the joint data set can increase the inversion resolution without the poor-quality data set being added into the inversion calculation. ERT investigation with borehole-to-surface array was employed in Chifeng in the northeast of Inner Mongolia, China. A smallscale was delineated with high-resolution, which is consistent with the drilling data.