Potential field from a dc current source arbitrarily located in a nonuniform layered medium

Sato, Hédison Kiuity

doi:10.1190/1.1444857

Cited by 14 publications

(9 citation statements)

References 9 publications

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“…The inversion of El‐log TD SIP data was performed using the AarhusInv (Auken et al, ) code, an integrated modeling and inversion code for electrical and electromagnetic data. Forward modeling of El‐log TD SIP data follows the recursive formulation by Sato () and takes into account the transmitter waveform and the receiver transfer function (Fiandaca et al, ).…”

Section: Methodsmentioning

confidence: 99%

Permeability Estimation Directly From Logging‐While‐Drilling Induced Polarization Data

Fiandaca

Maurya

Balbarini

et al. 2018

Water Resources Research

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In this study, we present the prediction of permeability from time domain spectral induced polarization (IP) data, measured in boreholes on undisturbed formations using the El‐log logging‐while‐drilling technique. We collected El‐log data and hydraulic properties on unconsolidated Quaternary and Miocene deposits in boreholes at three locations at a field site in Denmark, characterized by different electrical water conductivity and chemistry. The high vertical resolution of the El‐log technique matches the lithological variability at the site, minimizing ambiguity in the interpretation originating from resolution issues. The permeability values were computed from IP data using a laboratory‐derived empirical relationship presented in a recent study for saturated unconsolidated sediments, without any further calibration. A very good correlation, within 1 order of magnitude, was found between the IP‐derived permeability estimates and those derived using grain size analyses and slug tests, with similar depth trends and permeability contrasts. Furthermore, the effect of water conductivity on the IP‐derived permeability estimations was found negligible in comparison to the permeability uncertainties estimated from the inversion and the laboratory‐derived empirical relationship.

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Section: Methodsmentioning

confidence: 99%

Permeability Estimation Directly From Logging‐While‐Drilling Induced Polarization Data

Fiandaca

Maurya

Balbarini

et al. 2018

Water Resources Research

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“…The forward response and the Jacobian for the TD inversion are obtained through superposition of step responses computed by the fast Hankel transform as described in (Johansen & Sørensen 1979;Fiandaca et al 2013). For the inversion of the TDIP El-log data, the forward response is computed in 1-D following Fiandaca et al (2012) but using an FD kernel that allows buried electrodes as described in Sato (2000).…”

Section: Tdip Fdipmentioning

confidence: 99%

Field-scale comparison of frequency- and time-domain spectral induced polarization

Maurya

Fiandaca

Christiansen

et al. 2018

Geophysical Journal International

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In this paper we present a comparison study of the time-domain (TD) and frequency-domain (FD) spectral induced polarization (IP) methods in terms of acquisition time, data quality and spectral information retrieved from inversion. We collected TDIP and FDIP surface measurements on three profiles with identical electrode setups at two different field sites with different lithology. In addition, TDIP data were collected in two boreholes using the El-Log drilling technique in which apparent formation resistivity and chargeability values are measured during drilling using electrodes integrated within the stem auger. The TD and FD data were processed and inverted with similar approaches. The IP voltage decays and complex impedance spectra were inspected quadrupole by quadrupole for outliers. In the inversion, the apparent resistivity values and the full IP decays (in TD) or the full complex impedance spectra (in FD) for all quadrupoles were inverted simultaneously in 2-D using a modified parametrization of the Cole-Cole model. Furthermore, inversions of synthetic models mimicking the field situations were performed. The comparisons reveal that TD and FD results are comparable not only qualitatively, but also quantitatively. Furthermore, the surface inversions are in agreement with the borehole results and lithology, within the resolution capability of the surface measurements. In particular, comparable spectral IP parameters were retrieved for both sites with both measurement approaches, with relaxation times between 10 −2 s and 1 s, suggesting a spectral coverage at least up to 100 Hz for both TD and FD measurements. However, for the employed data acquisition procedures and instrumentations, the TD measurements had an advantage in terms of acquisition speed and usable spectral acquisition range compared to the FD measurements. We conclude that the TD method, as the FD method, is a suitable tool to recover spectral IP information in the field, provided that the measurement procedures are planned accordingly and the subsurface IP response is in the spectral range covered by the measurements.

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“…The first layer has a resistivity of 0.19 ·m and a thickness of 10.5 m, the second layer has a resistivity of 2.0 · m and a thickness of 6.0 m, and the third layer has a resistivity of 10.0 · m. The results of this modeling are shown on Figure 8 and indicate a good fitting between the experimental and the theoretical data. In order to minimize the effect of frequency we employed the data of the lowest frequency, 0.25 Hz, to compare with the algorithm of (Sato 2000), which was developed for the directcurrent case. The data represented in Figure 8 have been obtained with a different type of electrode and a different value of frequency from the data represented in Table I, resulting in very different data for n=1.…”

Section: Forward Modelingmentioning

confidence: 99%

“…We employed the algorithm developed by (Sato 2000) to compute forward models for the three sea levels of investigation. We used three layers for the initial model.…”

Section: Forward Modelingmentioning

confidence: 99%

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Apparent resistivity and spectral induced polarization in the submarine environment

Souza¹,

Sampaio

2001

An. Acad. Bras. Ciênc.

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Relatively few investigations have employed electrical methods in the submarine environment, which may be promising for mineral deposits or threatened by environmental problems. We have measured the electric field using both disk and bar electrodes in the sea water at three different levels: sea surface, seven meters deep, and sea bottom at a depth of ten meters, employing a 2 m spacing dipole-dipole array with 7 array spacings of investigation, and 13 values of frequencies at steps of (2 N hertz, N = -2, -1, 0, 1, 2,.....10). The measurement allowed the analysis of the electric field as a function of frequency and spacing, and of the spectral induced polarization. Modelling and interpretation of the apparent resistivity yielded a good fit with previous drilling data. Analysis of the spectrum of the complex apparent resistivity and the comparison with equivalent circuits, provided information about the grain size, the mineral composition and the major induced polarization phenomenon occurring below the sea. Therefore the result of the present research show the feasibility of measuring the variation of seawater resistivity in situ, as well as the resistivity of sea bottom sediments.

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Potential field from a dc current source arbitrarily located in a nonuniform layered medium

Cited by 14 publications

References 9 publications

Permeability Estimation Directly From Logging‐While‐Drilling Induced Polarization Data

Permeability Estimation Directly From Logging‐While‐Drilling Induced Polarization Data

Field-scale comparison of frequency- and time-domain spectral induced polarization

Apparent resistivity and spectral induced polarization in the submarine environment

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