Enhanced 3D visualization based on the inverse modeling of non-parallel 2D ERT profiles: An approach for assessing anomalous zone

Abstract

Abstract Three-dimensional resistivity models based on observed data in a grid pattern aids in understanding the volume and positional relations of subsurface regions having resistivity contrast with respect to the surrounding medium. However, acquiring ERT profiles in a regular 2D grid is labor intensive, time-consuming, and costly process. To overcome these constraints, pseudo 3D visualizations generated from multiple parallel 2D resistivity profiles are often used. Moreover, acquiring parallel 2D resistivity profiles in a grid is also often constraints by logistical challenges such as presence of utilities, waste mounds waterlogged patches etc. Therefore, in this work, a methodology is devised for creating a 3D database from inverse modeling results of multiple 2D resistivity profiles oriented in random direction in a region. In this approach, the azimuths of randomly oriented profiles are measured and utilized for introducing the y-coordinate. The proposed methodology is tested on 2D ERT datasets acquired at a chromite ore processing residue (COPR) waste dumping site.3D models generated through this approach has provided an enhanced visualization of conductive anomalous zones (i.e., < 15 Ohm.m) originating from the waste dump site. Further, the results obtained from the proposed methodology is compared with the quasi-3D volume generated by applying the 3D inversion algorithm on the compiled 2D ERT profiles datasets. The 3D visualization based on the proposed approach shows better correlation with anomalous zones present in the 2D inversion results of individual profiles. Thus, the methodology provides an efficient tool for creating 3D visualization models, and can be generalized for existing approaches...