Complex Electrical Resistivity and Dielectric Permittivity Responses to Dense Non-aqueous Phase Liquids' Imbibition and Drainage in Porous Media: A Laboratory Study

Abstract

The effective techniques for remediation of sites polluted by dense non-aqueous phase liquids (DNAPLs) remains a challenge. Among the various technical monitoring methods, there is an increasing interest in studying the geophysical characteristics of contaminated soils, as indicators of the progress in clean-up programs. This work sought to investigate the variation of the electrical complex resistivity and the relative permittivity by analyzing the results obtained from spectral induced polarization (SIP) and time domain reflectometry (TDR). Different series of measurements during drainage and imbibition of DNAPLs in porous media were done to validate the clean-up process on sites polluted by DNAPLs. Therefore, a methodology based on laboratory work was designed and carried out to study the electrical complex resistivity (both in magnitude and phase) in the frequency range 0.183 Hz to 20 kHz, and the relative dielectric permittivity at 70 MHz. The experiments were done on small 1D cells. In these cells, glass beads were used as a porous medium. Two different fluid couples, i.e., coal tar (CT)/water and canola oil (CO)/salty ethanol (SE), were used to produce two-phase flow. Our findings highlight that due to the high resistivity of CO and CT, an increase in water saturation led to decrease in amplitude and phase. Saturation change of SE had the same effect on resistivity but no relationship was found for phase and saturation for the mixture CO and SE. It is also showed that the complex resistivity and relative permittivity measurements were compatible with generalized Archie's law and complete complex refractive index method (CRIM) model as two empirical models for defining the correlation between the electrical resistivity, relative permittivity, and saturation of each phase in the multiphase porous medium.

Experimental study of electrical complex resistivity in a 2D multiphase porous medium under non‐isothermal conditions: Application to soil remediation monitoring

“…The slopes of the linear regression of the nine measurements at the top with GB+water and the bottom GB+CT are presented in Figure 3a,b. The obtained regression is in accordance with the previous finding by Iravani et al., 2020a, 2020b). Hayashi (2004) studied the linear relationship between electrical conductivity and temperature that was usually used in previous studies on water with different salinity and chemical substances.…”

“…In this study, we validate mixing models and calibration curves obtained from the previous study in cells and columns (Iravani et al, 2020a(Iravani et al, , 2020b) using a 2D two-phase flow and comparing the results with imaging for validation. In a previous study, Iravani et al (2020a) showed that both resistivity and phase are related to the temperature variation in 1D columns.…”

“…The study of geophysical parameters during remediation by the thermal enhanced method is influenced by two environmental parameters: temperature due to soil heating (Iravani et al, 2020a;Philippe et al, 2020) and saturation changes (Colombano et al, 2020;Iravani et al, 2020b) due to contamination pumping. In previous studies, we separately investigated the impact of temperature and saturation on electrical resistivity in contaminated saturated porous media with CT (Iravani et al, 2020a(Iravani et al, , 2020b.…”

“…Recently, Iravani et al (2020aIravani et al ( , 2020b) evaluated how temperature and saturation changes in two DNAPLs (coal tar and chlorinated solvent) affect complex electrical resistivity and relative permittivity. They used an oven to study temperature change and a 1D drainageimbibition system to study how saturation changed these two parameters.…”

Geoelectrical Method to Determine Andesite Rock Potential in Kepuh, Ciwandan District, Cilegon City

“…Furthermore, the information derived from borehole drilling always presents a local character, whereas geophysical imaging furnishes a regional reconstruction of buried structures' main features, at the scale of interest, in a faster and more economical fashion [11]. This method is widely used to address a variety of near-surface exploration problems including hydrogeological (e.g., [12]; [13]; [14]) environmental, and geotechnical studies (e.g., [15]; [16]; [17]). In addition, the results of 1D inversion of electrical sounding may be used in constituting starting models or a priori information for 2D/3D interpretations [18].…”