The dielectric constant of sandstones, 60 kHz to 4 MHz

Knight, Rosemary; Nur, Amos

doi:10.1190/1.1442332

Cited by 273 publications

(153 citation statements)

References 28 publications

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“…The plots for the rocks in this study are shown in Figure 1 (for dry rock samples) and Figure 2 (for partially saturated rock samples). Knight 11 as well as Knight and Nur 13 have established the existence of a critical frequency f 0 that separates the low frequency electrode polarization effects from high frequency bulk material polarization region of r   for Berea sandstones. In the present study, only few samples depict this critical frequency.…”

Section: Cole-cole Plotsmentioning

confidence: 99%

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Frequency-Dependent Electrical Characterization of Rock Types from Ewekoro, Eastern Dahomey Basin, Nigeria

et al. 2017

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Dielectric measurements (40 Hz-110 MHz) conducted on samples of limestone and its associated rocks from Ewekoro, Eastern Dahomey Basin, Nigeria has yielded vital information for characterization. Cole-Cole plots manifest a distribution of relaxation times in the rock samples common for multicomponent systems. All the rock types show dielectric dispersion in dry and partially saturated conditions, but the frequency range differs for the rock types and depends on wettability. At partial water saturation there is: (i) enhanced polarization resulting in increase in real and imaginary permittivities; (ii) shortened region of dielectric dispersion; (iii) broadened electrode polarization plateau; and (iv) steeper and shorter dispersion region. Irrespective of the state of the rocks, dielectric parameters for shale and glauconite are at least an order greater than for limestone and sandstone. Geometric or textural effects are partly responsible for the observed differences coupled with the presence of charged clay/clay-like particles in shale and glauconite. Decrease in relaxation and critical frequencies in partial saturation for shale in contrast to the increase in these frequencies for the other three rock types is due the effect of pore geometry on overall dielectric relaxation. This study shows that dielectric measurement can complement geochemical analysis in laboratory evaluation and characterization of rock raw materials.

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Section: Cole-cole Plotsmentioning

confidence: 99%

“…The efficient use of these tools depends on the understanding of the mechanisms of dielectric behaviour of rocks [11][12][13][14][15][16][17][18][19] . Broadband frequency dielectric measurement of heterogeneous media is based on the strong relationship between the fluid content and dielectric permittivity.…”

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confidence: 99%

Frequency-Dependent Electrical Characterization of Rock Types from Ewekoro, Eastern Dahomey Basin, Nigeria

et al. 2017

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“…However, due to the extraordinarily complex heterogeneity of porous rocks, there are still many disputes over the conductive and dielectric mechanisms in rocks (Clavier et al 1984;Zemanek 1989;Hamada and Al-Awad 1998). Scholars have proposed many conductive models for rocks, of which the most representative is the dual-water argillaceous sandstone conductive model proposed by Waxman andSmits in 1968 (Waxman andSmits 1968;Knight and Nur 1987;Hassoun et al 1997). …”

Section: Introductionmentioning

confidence: 99%

Study of the properties of non-gas dielectric capacitors in porous media

2015

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The size of pores and throats is at the nanometer scale in tight oil and shale gas zones, and the resistivity of these reservoirs is very high, so the reservoirs show more dielectric properties than conductivity properties. The conductive and dielectric characteristics of a parallel plate capacitor full of fresh water, NaCl solutions, and solid dielectrics, for example, sands are investigated in this paper, and the capacitance data of the non-gas capacitor are measured at different salinities and frequencies by a spectrum analyzer. The experimental results illustrate that the capacitance of this kind of capacitor is directly proportional to the salinity of the solutions and inversely proportional to the measuring frequency, the same as a vacuum parallel plate capacitor. The remarkable phenomenon, however, is that the capacitance is inversely proportional to the square of the distance between two plates. The specific characteristic of this capacitor is different from the conventional parallel plate capacitor. In order to explain this phenomenon, the paper proposed a new concept, named ''single micro ion capacitor'', and established a novel model to describe the characteristics of this particular capacitor. Based on this new model, the theoretical capacitance value of the single micro ion capacitor is calculated, and its polarization and relaxation mechanisms are analyzed.

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“…Each type of polarization will vanish past a certain frequency, which is determined by the inertial moment of the particles in question, frictions and electrostatic forces. They expressed that the electronic polarization, corresponding to rock permittivity, occurs at a range of 1Hz to approximately 1×10 8 Hz; molecular orientation, corresponding to the water molecular permittivity, occurs at range of 1Hz to approximately 1×10 10 Hz; and interfacial polarization, corresponding to pore geometry and ions, occurs at a range of 1Hz to approximately 1×10 16 Hz.…”

Section: Introductionmentioning

confidence: 99%

“…Earlier studies proved that most rocks and minerals show dielectric dispersion in the low-frequency region from a few Hz to several MHz. [15][16][17] At low frequencies, the dielectric dispersion of geological materials is believed to be caused by the polarization associated with charge buildup at the grain boundaries or grain imperfections. However, grain sizes and their distribution also control the frequency-dependent ε' values of the geological samples.…”

Section: Introductionmentioning

confidence: 99%

Dielectric Constant Properties of Tight Sandstone

Liu¹

2017

IPCSE

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This study stated dielectric properties of tight sandstone, which has porosity below 2%, and permeability below milli-Darcy. At this in-situs condition, the inter-pores are almost not connective, and throats are in micro-or nano-scale, so the electric conduction occupied weak position, but dielectric property predominated the current travelled through the rocks. Hence, the dielectric property is much significant characteristics should be investigated in order to better understand the electric mechanism of tight rocks. This paper illustrated the characteristics with experimental data from low to high frequency (Hz-kHz). Two parameters, resistivity and permittivity or dielectricity, were investigated with tight sandstone cores. The experiments were executed at room temperature (20˚C), the cores were injected into different content and salinity salt solution. The content, or say saturation of the solution in cores varied from 0-100% (in fact, completely salt solution) the salinity change from 0 (fresh water) to 1mg/mol. The experiment results showed that all of these two physical quantities, i.e. resistivity (R p ) and permittivity (Cp), have properties of frequency dispersion over the whole frequency range. Further analysis indicates that frequency dispersion of resistivity is relatively weak, but of dielectric, is much more obvious. That proved dielectric is more sensitive to saturation and salinity than resistivity, especially at low frequency. Two variables were introduced in order to describe the frequency dispersion properties D R and D C , which corresponded R p and C p respectively. D R and D C should indicate more detail account of the polarization and relaxation of components of tight sandstone cores, which will be further discussed in other paper.

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The dielectric constant of sandstones, 60 kHz to 4 MHz

Cited by 273 publications

References 28 publications

Frequency-Dependent Electrical Characterization of Rock Types from Ewekoro, Eastern Dahomey Basin, Nigeria

Frequency-Dependent Electrical Characterization of Rock Types from Ewekoro, Eastern Dahomey Basin, Nigeria

Study of the properties of non-gas dielectric capacitors in porous media

Dielectric Constant Properties of Tight Sandstone

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