Relationship between spectral induced polarization and hydraulic properties of saturated and unsaturated sandstone

Abstract

[1] There is growing interest in the use of geophysical methods for hydrological model parameterization. Empirical induced polarization (IP)-hydraulic conductivity (K) relationships have been developed, but these are only applicable to sediments in which the IP response shows limited variation with electrical current frequency. Here we examine the spectral IP response of samples taken from a UK sandstone aquifer and compare measured parameters with physical and hydraulic properties. We demonstrate the limited value of existing IP-K models due to the inherent IP frequency dependence of these samples. Our results show how the mean relaxation time, t, is a more appropriate measure of IP response for these sediments. A significant inverse correlation between the surface area to pore volume ratio and t is observed, suggesting that t is a measure of a characteristic hydraulic length scale. This is supported by a measured strong positive correlation between log t and log K. Our measurements also reveal evidence of a relationship between t and a dominant pore throat size, which leads to postulations about the parallelism between the spectral IP behavior and unsaturated hydraulic characteristics. Additional experiments show how the relaxation time is affected by degree of fluid saturation, indicating that saturation levels must be accounted for if our empirical relationships are applied to vadose zone studies. Our results show clear evidence of the potential value of frequency-based IP measurements for parameterization of groundwater flow models.

Dependence of spectral‐induced polarization response of sandstone on temperature and its relevance to permeability estimation

“…When taking b = 3.85, for instance, as reported by Binley et al [2005] and a = 0.90, the apparent permeability varies by more than 2 orders of magnitude in the temperature range from 0°C to 80°C. The temperature dependence of k a becomes significantly weaker when using lower values of b as reported, for example, by Tong et al [2006] and Zisser et al [2010].…”

“…Empirical relationships between hydraulic permeability k and t in the form of a power law were correspondingly reported [e.g., Binley et al, 2005;Tong et al, 2006;Zisser et al, 2010]:…”

Induced polarization signatures of cations exhibiting differential sorption behaviors in saturated sands

“…Mechanistic models of spectral induced polarization started to emerge 20 years ago in geophysics to predict the electrical behavior of porous materials below 10 kHz [de Lima and Sharma, 1992;Lesmes and Morgan, 2001]. However, these models were mainly developed to connect spectral induced polarization spectra to textural properties such as permeability [Slater and Lesmes, 2002b;Binley et al, 2005]. Until recently, these models were not connected to a full description of the electrical double-layer theory or, more importantly, to a speciation model between the components of the pore water and the mineral surface.…”

Complex conductivity of soils

“…Induced polarization has many applications in hydrogeophysics including inference of hydraulic properties (Binley et al [2005]; Weller et al [2010], Joseph et al [2015]; Nordsiek et al [2015]), facies discrimination , the detection of contaminants in soils (e.g., Sogade et al [2006], Flores Orozco et al [2012], Schwartz and Furman [2012], Schmutz et al [2012], Chen et al [2013]), and the detection of cracks (e.g., Okay et al [2013]). Induced polarization has shown also a unique capability to monitor non-intrusively sorption processes in the electrical double layer (Vaudelet et al [2011a, b], Hao et al [2016]) and precipitation of metallic particles during redox-controlled reactions (e.g., Mewafy et al 4 [2013], Abdulsamad [2017]).…”