Numerical simulations of measurement error and 10 electrode arrays on 2D resistivity image profile
Speaker: Ze-Zong Lin
Abstract
Electrode spacing errors and observed potential error are two key factors that affect the data quality for DC resistivity imaging measurements. In this study, we investigate the properties and effects of these two kinds of error on 2D resistivity imaging or inversion for practical applications. Furthermore, a robust inversion and a smoothness-constrained inversion were applied to the investigation of the effects of the measurement errors. Using real data set, we show that the smoothness-constrained least-squares inversion is much more sensitive to the potential errors than the robust inversion, but the two inversion schemes produce very similar models with a high data quality. Numerical simulations are used to compare the resolution and efficiency of 2D resistivity imaging surveys for 10 electrode arrays. The arrays analysed include pole -pole (PP), pole-dipole (PD), half-Wenner (HW), Wenner- £\ (WN), Schlumberger (SC), dipole-dipole (DD), Wenner- £] (WB), £^ -array (GM), multiple or moving gradient array (GD) and midpoint-potential-referred measurement (MPR) arrays. Five synthetic geological models, simulating a buried channel, a narrow conductive dike, a narrow resistive dike, dipping blocks and covered waste ponds, were used to examine the surveying efficiency (anomaly effects, signal-to-noise ratios) and the imaging capabilities of these arrays. According to the final result, GD, PD, DD and SC arrays are strongly recommended for 2D resistivity imaging, where the final choice will be determined by the expected geology, the purpose of the survey and logistical considerations.
Reference
Bing Zhou and Torleif Dahlin, 2003. Properties and effects of measurement errors on 2D resistivity imaging surveying. Near Surface Geophysics, 105-117.
Torleif Dahlin and Bing Zhou, 2004. A numerical comparison of 2D resistivity imaging with 10 electrode arrays. Geophysical Prospecting 52, 379-398.