Laboratory determination of the complex conductivity tensor of unconventional anisotropic shales

Woodruff, W. F.; Revil, A.; Torres‐Verdín, Carlos

doi:10.1190/geo2013-0367.1

Cited by 31 publications

(31 citation statements)

References 47 publications

(75 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…We see that the trend displayed by the soil is consistent with other data sets. The soil samples investigated in the present paper are characterized by higher surface and quadrature conductivities than the core samples investigated in previous studies [see, for instance, Weller et al, 2013;Woodruff et al, 2014;Revil et al, 2014bRevil et al, , 2017aRevil et al, , 2017b. Figure 18 validates equation (16) in providing a mean value of the dimensionless number R, this value being valid for several data sets.…”

Section: Quadrature Versus Surface Conductivitiessupporting

confidence: 80%

See 1 more Smart Citation

Complex conductivity of soils

Revil

Coperey

Shao

et al. 2017

Water Resources Research

138

191

View full text Add to dashboard Cite

The complex conductivity of soils remains poorly known despite the growing importance of this method in hydrogeophysics. In order to fill this gap of knowledge, we investigate the complex conductivity of 71 soils samples (including four peat samples) and one clean sand in the frequency range 0.1 Hz to 45 kHz. The soil samples are saturated with six different NaCl brines with conductivities (0.031, 0.53, 1.15, 5.7, 14.7, and 22 S m−1, NaCl, 25°C) in order to determine their intrinsic formation factor and surface conductivity. This data set is used to test the predictions of the dynamic Stern polarization model of porous media in terms of relationship between the quadrature conductivity and the surface conductivity. We also investigate the relationship between the normalized chargeability (the difference of in‐phase conductivity between two frequencies) and the quadrature conductivity at the geometric mean frequency. This data set confirms the relationships between the surface conductivity, the quadrature conductivity, and the normalized chargeability. The normalized chargeability depends linearly on the cation exchange capacity and specific surface area while the chargeability shows no dependence on these parameters. These new data and the dynamic Stern layer polarization model are observed to be mutually consistent. Traditionally, in hydrogeophysics, surface conductivity is neglected in the analysis of resistivity data. The relationships we have developed can be used in field conditions to avoid neglecting surface conductivity in the interpretation of DC resistivity tomograms. We also investigate the effects of temperature and saturation and, here again, the dynamic Stern layer predictions and the experimental observations are mutually consistent.

show abstract

Section: Quadrature Versus Surface Conductivitiessupporting

confidence: 80%

“…Note that the soil samples (in red) are characterized by higher surface conductivity and quadrature conductivity than the other core samples investigated to date. The other data for sedimentary rocks are from Weller et al [2013], Woodruff et al [2014], and Revil et al [2014b]. The data for the volcanic rocks are from Revil et al [2017a, b].…”

Section: Börnermentioning

confidence: 99%

Complex conductivity of soils

Revil

Coperey

Shao

et al. 2017

Water Resources Research

138

191

View full text Add to dashboard Cite

show abstract

“…The samples were first dried during 24 hr at about 50 °C and then saturated under vacuum with the solutions (see Woodruff et al, , for a detail of this procedure). The samples were left at least 1 month in the solution in order to reach complete equilibrium.…”

Section: Methodsmentioning

confidence: 99%

Low‐Frequency Induced Polarization of Porous Media Undergoing Freezing: Preliminary Observations and Modeling

et al. 2019

View full text Add to dashboard Cite

We investigate the thermal dependence of the complex conductivity of nine porous materials in the temperature range +20°C to −10 or −15°C. The selected samples include three soils, two granites, three clay-sands mixes, and one graphitic tight sandstone. A total of 12 experiments is conducted with one sample tested at three different salinities. Our goal is to use this database to extend the dynamic Stern layer polarization model in freezing conditions. We observe two polarization mechanisms, one associated with the effect of the change in the liquid water content and its salinity upon the polarization of the porous material. A second mechanism, at higher frequencies (>10 Hz), is likely associated with the polarization of ice. At low frequencies and above the freezing point, the in-phase and quadrature conductivities depend on temperature in a predictable way. This dependence is due to the dependence of the mobility of the charge carriers with temperature. Below the freezing point, the in-phase and quadrature conductivity follow a brutal decay with temperature. This dependence is modeled through an exponential freezing curve function. We were also able to determine how the (apparent) formation factor and surface conductivity change with temperature and water content below the freezing point. Our model is able to replicate the data at low frequencies and predicts correctly the fact that the ratio between the normalized chargeability and the surface conductivity is independent of the water content and temperature and equals a well-defined dimensionless number R.

show abstract

“…stand the complex conductivity of low-porosity gas shales by Revil et al (2013) and Woodruff et al (2014).…”

Section: D364mentioning

confidence: 99%

Quadrature conductivity: A quantitative indicator of bacterial abundance in porous media

et al. 2014

Self Cite

View full text Add to dashboard Cite

The abundance and growth stages of bacteria in subsurface porous media affect the concentrations and distributions of charged species within the solid-solution interfaces. Therefore, spectral induced polarization (SIP) measurements can be used to monitor changes in bacterial biomass and growth stage. Our goal was to gain a better understanding of the SIP response of bacteria present in a porous material. Bacterial cell surfaces possess an electric double layer and therefore become polarized in an electric field. We performed SIP measurements over the frequency range of 0.1-1 kHz on cell suspensions alone and cell suspensions mixed with sand at four pore water conductivities. We used Zymomonas mobilis at four different cell densities (including the background). The quadrature conductivity spectra exhibited two peaks, one around 0.05-0.10 Hz and the other around 1-10 Hz. Because SIP measurements on bacterial suspensions are typically made at frequencies greater than 1 Hz, these peaks have not been previously reported. In the bacterial suspensions in growth medium, the quadrature conductivity at peak I was linearly proportional to the density of the bacteria. For the case of the suspensions mixed with sands, we observed that peak II presented a smaller increase in the quadrature conductivity with the cell density. A comparison of the experiments with and without sand grains illustrated the effect of the porous medium on the overall quadrature conductivity response (decrease in the amplitude and shift of the peaks to the lower frequencies). Our results indicate that for a given porous medium, time-lapse SIP has potential for monitoring changes in bacterial abundance within porous media.

show abstract

Laboratory determination of the complex conductivity tensor of unconventional anisotropic shales

Cited by 31 publications

References 47 publications

Complex conductivity of soils

Complex conductivity of soils

Low‐Frequency Induced Polarization of Porous Media Undergoing Freezing: Preliminary Observations and Modeling

Quadrature conductivity: A quantitative indicator of bacterial abundance in porous media

Contact Info

Product

Resources

About