scholarly journals The use of the fractal model to complex resistivity in the interpretation of induced polarization data

2013 ◽  
Vol 37 (3) ◽  
pp. 1347-1361 ◽  
Author(s):  
V.J.da C. Farias ◽  
B.R.P. da Rocha ◽  
M.P.da C. da Rocha ◽  
H.R. Tavares
Keyword(s):  
Fractal Model ◽  
Induced Polarization ◽  
Polarization Data ◽  
Complex Resistivity

Synthetic and field-based electrical imaging of a zerovalent iron barrier: Implications for monitoring long-term barrier performance

Geophysics ◽  
2006 ◽  
Vol 71 (5) ◽  
pp. B129-B137 ◽  
Author(s):  
Lee Slater ◽  
Andrew Binley
Keyword(s):  
Electrical Properties ◽  
Internal Structure ◽  
Induced Polarization ◽  
Permeable Reactive Barrier ◽  
Zerovalent Iron ◽  
Polarization Data ◽  
Complex Resistivity ◽  
Electrical Imaging ◽  
Over Time

We performed a study of electrical imaging sensitivity to geochemical alteration of a zerovalent iron permeable reactive barrier (PRB) over time. Complex-resistivity measurements of laboratory cores from an operational PRB defined the electrical properties of both unreacted and geochemically altered (reacted) iron, as well as the growth rate of the reacted front on the up gradient edge of the barrier. Laboratory results were used to generate models of the electrical structure of the PRB at 0, 15, and 30 years of operation. Synthetic cross-borehole resistivity and induced-polarization data were generated and perturbed with errors representative of noise at the site. To generate reliable images of the engineered structure, a complex-resistivity inversion was employed with a disconnect in the regularization between the part of the finite-element mesh (FEM) representing the internal structure of the barrier and the remainder of the FEM mesh.Synthetic results show that although the internal structure of inverted images at 15 and 30 years does not accurately reflect the width of the reacted front, modeled along the up-gradient edge of the barrier, perturbations to the internal structure of the imaged PRB are diagnostic of the growth of the reacted front. Cross-borehole electrical data, obtained at the field site during a 15-month period, demonstrate that the complex-resistivity algorithm can resolve reliably the PRB target using the engineering design specifications to define the correct shape of the regularization disconnect. Both resistivity and induced-polarization reciprocal errors are low, and the induced-polarization data are highly repeatable over this period. Changes in the electrical properties of the PRB over time were small but consistent with growth of a reacted front, based on the synthetic study. Significantly, resistivity imaging alone may be sufficient for long-term monitoring of precipitation, leading to reduced PRB performance.

Reliability of Time Domain Induced Polarization Data

2011 ◽  
Author(s):  
Aurélie Gazoty ◽  
Esben Auken ◽  
Jesper Pedersen ◽  
Gianluca Fiandaca ◽  
Anders Vest Christiansen
Keyword(s):  
Time Domain ◽  
Induced Polarization ◽  
Polarization Data

Inversion of induced polarization data

Geophysics ◽  
1994 ◽  
Vol 59 (9) ◽  
pp. 1327-1341 ◽  
Author(s):  
Douglas W. Oldenburg ◽  
Yaoguo Li
Keyword(s):  
Inverse Problem ◽  
Objective Function ◽  
Effective Conductivity ◽  
Optimization Theory ◽  
Induced Polarization ◽  
Dc Resistivity ◽  
Earth Structure ◽  
Nonlinear Inverse Problem ◽  
Polarization Data ◽  
The Earth

We develop three methods to invert induced polarization (IP) data. The foundation for our algorithms is an assumption that the ultimate effect of chargeability is to alter the effective conductivity when current is applied. This assumption, which was first put forth by Siegel and has been routinely adopted in the literature, permits the IP responses to be numerically modeled by carrying out two forward modelings using a DC resistivity algorithm. The intimate connection between DC and IP data means that inversion of IP data is a two‐step process. First, the DC potentials are inverted to recover a background conductivity. The distribution of chargeability can then be found by using any one of the three following techniques: (1) linearizing the IP data equation and solving a linear inverse problem, (2) manipulating the conductivities obtained after performing two DC resistivity inversions, and (3) solving a nonlinear inverse problem. Our procedure for performing the inversion is to divide the earth into rectangular prisms and to assume that the conductivity σ and chargeability η are constant in each cell. To emulate complicated earth structure we allow many cells, usually far more than there are data. The inverse problem, which has many solutions, is then solved as a problem in optimization theory. A model objective function is designed, and a “model” (either the distribution of σ or η)is sought that minimizes the objective function subject to adequately fitting the data. Generalized subspace methodologies are used to solve both inverse problems, and positivity constraints are included. The IP inversion procedures we design are generic and can be applied to 1-D, 2-D, or 3-D earth models and with any configuration of current and potential electrodes. We illustrate our methods by inverting synthetic DC/IP data taken over a 2-D earth structure and by inverting dipole‐dipole data taken in Quebec.

On: “Recent Advances and Applications in Complex Resistivity Measurements,” by K. L. Zonge and J. C. Wynn (GEOPHYSICS, Oct. 1975, p. 851–864)

Geophysics ◽  
1977 ◽  
Vol 42 (1) ◽  
pp. 120-121 ◽  
Author(s):  
P. H. Nelson ◽  
G. D. Van Voorhis
Keyword(s):  
Spectral Data ◽  
Induced Polarization ◽  
Complex Resistivity ◽  
Resistivity Measurements ◽  
Recent Advances ◽  
Measuring Techniques

In presenting a variety of induced polarization spectral data, Zonge and Wynn refer to a paper published earlier by us (Van Voorhis et al., 1973) which deals with the same topic. We feel Zonge and Wynn have misrepresented our measuring techniques, data, and conclusions in their references to our paper. Our principal objections center on three statements by the authors.

A hybrid correlation denoising method based on complex resistivity and application on spread spectrum induced polarization data

Geophysics ◽  
2021 ◽  
pp. 1-35
Author(s):  
Siming He ◽  
Jian Guan ◽  
Yi Wang ◽  
Xiu Ji ◽  
Hui Wang
Keyword(s):  
Hybrid Method ◽  
Spread Spectrum ◽  
Field Experiments ◽  
Noise Suppression ◽  
Random Noise ◽  
Induced Polarization ◽  
Data Simulation ◽  
Denoising Method ◽  
Complex Resistivity ◽  
Geophysical Surveys

In electrical exploration techniques, an effective suppression method for Gaussian and impulsive random noise in spread spectrum induced polarization (SSIP) continues to be challenging for conventional denoising methods. Remnant noise influences the complex resistivity spectrum and damages the subsequent interpretation of geophysical surveys. We present a hybrid method based on a correlation function and complex resistivity, which introduces the correlation analyses between the transmitting source, the measured potential, and the injected current signal. According to the analyses, reliable results for complex resistivity spectra can be calculated, which can be further used for noise suppression. We apply the hybrid method to both numerical and field experiments to process measured SSIP data. Simulation tests show that the hybrid method not only suppresses the two types of noise but also improves the relative error of the complex resistivity spectrum. Field data processing shows that the hybrid method can minimize the standard deviation of the data and possess a greater ability to distinguish adjacent objects, which can improve the reliability of the data in subsequent processing and interpretation.

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