Modelling the spectral induced polarization response of water-saturated sands in the intermediate frequency range (10²–10⁵ Hz) using mechanistic and empirical approaches

Abstract

The intermediate frequency range 10 2-10 5 Hz forms the transition range between the spectral induced polarization frequency domain and the dielectric spectroscopy frequency domain. Available experimental data showed that the spectral induced polarization response of sands fully saturated with water was particularly sensitive to variations of the saturating water electrical conductivity value in the intermediate frequency range. An empirical and a mechanistic model have been developed and confronted to this experimental data. This confrontation showed that the Maxwell Wagner polarization alone is not sufficient to explain the observed signal in the intermediate frequency range. The SIP response of the media was modelled by assigning relatively high dielectric permittivity values to the sand particle or high effective permittivity values to the media. Such high values are commonly observed in the dielectric spectroscopy literature when entering the intermediate frequency range. The physical origin of these high dielectric permittivity values is discussed (grain shape, electromagnetic coupling), and a preliminary study is presented which suggests that the high impedance values of the non-polarizable electrodes might play a significant role in the observed behaviour.

Joint inversion of NMR and SIP data to estimate pore size distribution of geomaterials

“…use of 100ε 0 as the high frequency permittivity ε inf is consistent with experimental measurements (e.g. see Jougnot et al 2010;Kremer et al 2016). The origin of this abnormally high value (for comparison, the permittivity of pure water is ∼79ε 0 ) is still unclear and it could be caused by Maxwell-Wagner polarization, grain shape influence, inductive electromagnetic coupling or electrode influence (Kremer et al 2016).…”

“…In SIP porosimetry, the interfacial polarization and dielectric effects may also be considered. However, the theory combing EDL polarization, interfacial polarization, and dielectric polarization still significantly underestimates the measured permittivity of sandstones (Lesmes & Morgan 2001;Kremer et al 2016). Lastly, although not stated explicitly, SIP porosimetry applies the isolated pore model, which assumes the ion movement is limited to a single pore or EDL.…”

“…see Jougnot et al 2010;Kremer et al 2016). The origin of this abnormally high value (for comparison, the permittivity of pure water is ∼79ε 0 ) is still unclear and it could be caused by Maxwell-Wagner polarization, grain shape influence, inductive electromagnetic coupling or electrode influence (Kremer et al 2016). The applied minimum and maximum frequencies are 10 −3 Hz and 100 kHz, respectively, and the total number of SIP measurements is 50.…”

“…In SIP experiments, a Cole-Cole model is used to describe the unknown polarization that might be responsible for the anomalously high permittivity at intermediate frequencies (e.g. Lesmes & Morgan 2001;Kremer et al 2016). Thus, the complex conductivity is calculated by combing eqs (7) and (13) and the added Cole-Cole model.…”

Laboratory monitoring of CO2injection in saturated silica and carbonate sands using spectral induced polarization

“…By working with a relatively simple medium, but still representative of the kind of material one can encounter in the subsurface (such as sandy aquifers), we aim to understand the first-order physicochemical phenomena induced by a CO 2 leakage in the shallow subsurface and observe whether they may have a consequent impact on SIP parameter magnitude. In a companion paper (Kremer et al 2016), we present an extended modeling work that brings valuable elements toward a better understanding of the experimental data presented here.…”