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

2019 ◽  
Vol 124 (5) ◽  
pp. 4523-4544 ◽  
Author(s):  
A. Coperey ◽  
A. Revil ◽  
F. Abdulsamad ◽  
B. Stutz ◽  
P. A. Duvillard ◽  
...  
Keyword(s):  
Porous Media ◽  
Low Frequency ◽  
Induced Polarization

scholarly journals The Generalized Skin Depth for Polarized Porous Media Based on the Cole–Cole Model

2020 ◽  
Vol 10 (4) ◽  
pp. 1456
Author(s):  
Yanju Ji ◽  
Xiangdong Meng ◽  
Jingya Shao ◽  
Yanqi Wu ◽  
Qiong Wu
Keyword(s):  
Porous Media ◽  
Electromagnetic Wave ◽  
Frequency Domain ◽  
Low Frequency ◽  
Theoretical Data ◽  
Data Interpretation ◽  
Induced Polarization ◽  
Skin Depth ◽  
Imaging Results ◽  
Frequency Excitation

In the field of frequency-domain electromagnetic detection, skin depth is an important parameter for electromagnetic data interpretation and imaging. The classic skin depth formula is calculated based only on conductivity; the induced-polarization effect in real earth is not considered, so the imaging results have obvious errors. To solve these problems, based on plane wave theory and the Cole–Cole conductivity model, a generalized skin depth formula of polarized media is derived in the frequency domain. The accuracy of the generalized skin depth is verified through comparison with the classical skin depth. To show the practicability of this study, the theoretical data with induced polarization (IP) effects are used to explain the generalized skin depth for polarized porous media. The generalized skin depth calculation for a typical porous polarization model is related not only to conductivity, but also to polarization parameters, such as chargeability, characteristic time constant, and frequency dependence. At low-frequency excitation, the generalized skin depth formula can be used to calculate the propagation depth of electromagnetic waves relatively accurately for porous polarized media. This method can be applied to the calculation of electromagnetic wave propagation depths in complex dispersive media. Compared with non-polarized media, in porous polarized media, under low-frequency excitation, the electromagnetic wave propagates deeper, allowing the detection of deeper objects. The data interpretation and imaging of polarized porous media by the generalized skin depth formula have higher accuracy.

On the low frequency permittivity of liquid-filled porous media

1994 ◽  
Vol 90 (3) ◽  
pp. 201-204 ◽  
Author(s):  
B. Nettelblad ◽  
G.A. Niklasson
Keyword(s):  
Porous Media ◽  
Low Frequency

Investigation of Low Frequency Elastic Wave Application for Fluid Flow Percolation Enhancement in Fractured Porous Media

2013 ◽  
Vol 31 (11) ◽  
pp. 1159-1167 ◽  
Author(s):  
B. Keshavarzi ◽  
R. Karimi ◽  
I. Najafi ◽  
M. H. Ghazanfari ◽  
M. Amani ◽  
...  
Keyword(s):  
Porous Media ◽  
Fluid Flow ◽  
Elastic Wave ◽  
Low Frequency ◽  
Fractured Porous Media

Mapping of induced polarization using natural fields

Geophysics ◽  
2001 ◽  
Vol 66 (1) ◽  
pp. 137-147 ◽  
Author(s):  
Erika Gasperikova ◽  
H. Frank Morrison
Keyword(s):  
Electric Field ◽  
Surrounding Medium ◽  
Low Frequency ◽  
Induced Polarization ◽  
The Body ◽  
Electromagnetic Response ◽  
Frequency Dependent ◽  
Finite Body ◽  
Electric Field Profile ◽  
Measured Response

The observed electromagnetic response of a finite body is caused by induction and polarization currents in the body and by the distortion of the induction currents in the surrounding medium. At a sufficiently low frequency, there is negligible induction and the measured response is that of the body distorting the background currents just as it would distort a direct current (dc). Because this dc response is not inherently frequency dependent, any observed change in response of the body for frequencies low enough to be in this dc limit must result from frequency‐dependent conductivity. Profiles of low‐frequency natural electric (telluric) fields have spatial anomalies over finite bodies of fixed conductivity that are independent of frequency and have no associated phase anomaly. If the body is polarizable, the electric field profile over the body becomes frequency dependent and phase shifted with respect to a reference field. The technique was tested on data acquired in a standard continuous profiling magnetotelluric (MT) survey over a strong induced polarization (IP) anomaly previously mapped with a conventional pole‐dipole IP survey. The extracted IP response appears in both the apparent resistivity and the normalized electric field profiles.

scholarly journals Quantifying Induced Polarization of Conductive Inclusions in Porous Media and Implications for Geophysical Measurements

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Lang Feng ◽  
Qiuzi Li ◽  
Stephen D. Cameron ◽  
Kuang He ◽  
Robert Colby ◽  
...  
Keyword(s):  
Porous Media ◽  
Induced Polarization ◽  
Geophysical Measurements

Theory of induced‐polarization logging in a borehole

Geophysics ◽  
1986 ◽  
Vol 51 (9) ◽  
pp. 1830-1849 ◽  
Author(s):  
R. Freedman ◽  
J. P. Vogiatzis
Keyword(s):  
Low Frequency ◽  
Induced Polarization ◽  
Time Dependent ◽  
Frequency Effect ◽  
Frequency Interval ◽  
Nonlinear Relationship ◽  
Theoretical Understanding ◽  
Resistivity Logging ◽  
Downhole Measurements ◽  
Phase Angles

Currently, there is interest by the petroleum well‐logging industry in the potential use of induced polarization (IP) measurements to improve formation evaluation in shaly sands. Shell Development Company has constructed an experimental four‐electrode IP and resistivity logging tool to obtain downhole measurements in shaly sands. This study contributes to the theoretical understanding and interpretation of the dynamic (i.e., time‐dependent) response of this type of downhole IP logging device. A low‐frequency (e.g., 32 Hz or less) electric current oscillating at a single fixed frequency is applied between a pair of current electrodes in a borehole. The resulting voltages induced between pairs of potential measuring electrodes in the borehole are calculated by solving the time‐dependent Maxwell’s equations. Inductive electromagnetic (EM) coupling contributions to apparent (e.g., measured) IP phase angles are automatically taken into account. The model is applied to the study of normal logging arrays for which the voltage measuring electrodes are interior to the current electrodes. The model responses are calculated for normal arrays in both infinitely thick noninvaded formations and infinitely thick invaded formations. EM coupling contributions to apparent IP phase angles have an approximately universal dependence on a scaling parameter defined here. The scaling relationship permits the quantitative estimate of EM coupling effects for specific tool parameters (i.e., electrode spacings and frequencies) and formation characteristics (i.e., apparent conductivities). Therefore, scaling relationships of this type should be useful in the design of IP tools. An inverse method, developed for determining true formation IP phase angles and resistivities from apparent values measured by an IP tool, utilizes data from multiple pairs of voltage‐measuring electrodes and exploits the fact that, for the systems of interest, the inverse resistivity and IP problems can be “decoupled.” The assumption that IP phase angles have a logarithmic dependence on frequency over a decade frequency interval leads to a nonlinear relationship between percent frequency effect (PFE) and IP phase angle. This nonlinear relationship agrees well with experimental data.

On charge accumulation in heterogeneous porous rocks under the influence of an external electric field

Geophysics ◽  
2013 ◽  
Vol 78 (4) ◽  
pp. D271-D291 ◽  
Author(s):  
A. Revil
Keyword(s):  
Porous Media ◽  
Electric Field ◽  
Effective Permittivity ◽  
Low Frequency ◽  
Free Water ◽  
Planck Equation ◽  
Charge Accumulation ◽  
Porous Rocks ◽  
Stern Layer ◽  
Charge Polarization

Electric polarization is described as the sum of charge accumulations (free charge density) and orientation of polar molecules such as those of bound and free water molecules (bound charge polarization). Charge accumulation in porous materials cannot be described with Ohm’s law alone. Nonequilibrium thermodynamics or the upscaling of the local Nernst-Planck equation imply that the drift of ions in porous media is controlled by the gradient of their electrochemical potentials and not solely by the electric field. In porous media, electrochemical capacitance is at least six to eight orders of magnitude larger than electrostatic capacitance associated with bound charge polarization. In other words, the low-frequency ([Formula: see text]) effective permittivity entering Ampère’s law is six to eight orders of magnitude larger than high-frequency dielectric permittivity (measured for instance at 1 GHz). Low-frequency polarization of porous media, with no metallic particles (no electronic conductors and semiconductors) is controlled by polarization of the inner component of the electrical double layer coating the grains. This layer, called the “Stern layer,” plays a strong role in defining the cation exchange capacity of a material. A polarization model based on the polarization of the Stern layer explains a large number of experimental observations and could be used in the interpretation of hydro- and petroleum geophysical measurements.

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