Calculation of conductivity and depth correction factors for the S-layer differential transformFN1

Magdel Combrinck

doi:10.1071/EG08014

ISSN: 0812-3985
E-ISSN: 1834-7533

Calculation of conductivity and depth correction factors for the S-layer differential transformFN1
Authors Magdel Combrinck^a
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^a 121 Rosen Office Park, 37 Invicta Rd, Halfway Gardens, Gauteng 1685, South Africa. Email: [email protected]
Publisher: Australian Society of Exploration Geophysicists
Source: Exploration Geophysics, Volume 39, Issue 2, Jun 2008, p. 133 - 138
DOI: https://doi.org/10.1071/EG08014
- Received: 05 Dec 2007
- Accepted: 27 Apr 2008
- Published online: 01 Jun 2008

Abstract

The VTEM system developed and operated by Geotech Limited and Geotech Airborne Limited is a central loop configuration system lending itself to many traditional ground interpretation strategies. One of these is the S-layer (thin, conductive layer) differential transform that is used to generate resistivity-depth sections. An empirical study indicated that delineating conductors in a conductive half space necessitates the implementation of a scale factor in order to obtain the correct depths and conductivity values when applying the S-layer differential transform.

Based on an empirical approach, there was found to be an infinite number of depth correction factors that will still yield acceptable conductivity values, and the need arose to explain the origin of this discrepancy and to find the correct depth correction factor. A correction strategy was followed, based on scaling results to yield exact conductivities when applied to half-space models. Assuming that the equivalent filament for the S-layer behaviour, as with the equivalent filament for the half-space behaviour, does not coincide with the electric field maxima in the subsurface led to a plausible depth correction factor which was validated on various synthetic models.

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References

Eaton P. A. Hohmann G. W. 1989 A rapid inversion technique for transient electromagnetic soundings: Physics of the Earth and Planetary Interiors 53 384 404 doi:10.1016/0031-9201(89)90025-3
[Google Scholar]
Fullagar P. K. 1989 Generation of conductivity-depth pseudo-sections from coincident loop and in-loop TEM data: Exploration Geophysics 20 43 45 doi:10.1071/EG989043
[Google Scholar]
James B. A. 1988, Detection of tunnels by transient electromagnetic subsurface imaging: U S Geological Survey Open-File Report (United States).
Kaufman A. A. , and Keller G. V. 1983, Frequency and Transient Soundings: Methods in Geochemistry and Geophysics 16 Elsevier Science.
Macnae J. Lamontagne Y. 1987 Imaging quasi-layered conductive structures by simple processing of transient electromagnetic data: Geophysics 52 545 554 doi:10.1190/1.1442323
[Google Scholar]
Nabighian M. N. , and Macnae J. C. 1991, Time Domain Electromagnetic prospecting Methods, in M. N. Nabighian ed., Electromagnetic Methods in Applied Geophysics, Volume 2, Application: Soc. of Expl. Geophysicists: 427–520.
Nekut A. G. 1987 Direct inversion of time-domain electromagnetic data: Geophysics 52 1431 1435 doi:10.1190/1.1442256
[Google Scholar]
Sidorov V. A. , and Tikshaev V. V. 1969, Electrical prospecting with transient field in near zone: Saratov University (in Russian).
Smith R. S. Edwards R. N. Buselli G. 1994 An automatic technique for presentation of coincident-loop, impulse-response, transient, electromagnetic data: Geophysics 59 1542 1550 doi:10.1190/1.1443543
[Google Scholar]
Spies B. R. , and Frischknecht F. C. 1991, Electromagnetic Sounding, in M. N. Nabighian ed., Electromagnetic Methods in Applied Geophysics, Volume 2, Application: Soc. of Expl. Geophysicists: 285–425.
Tartaras E. Zhdanov M. S. Wada K. Saito A. Hara T. 2000 Fast imaging of TDEM data based on S-inversion: Journal of Applied Geophysics 43 15 32 doi:10.1016/S0926-9851(99)00030-0
[Google Scholar]
Wolfgram P. Karlik G. 1995 Conductivity-depth transform of GEOTEM data: Exploration Geophysics 26 179 185 doi:10.1071/EG995179
[Google Scholar]
Wolfgram P. Hyde M. Thomson S. 1998 How to find localised conductors in GEOTEM data: Exploration Geophysics 29 665 670 doi:10.1071/EG998665
[Google Scholar]
Zhdanov M. S. Pavlov D. 2001 Analysis and interpretation of anomalous conductivity and magnetic permeability effects in time domain electromagnetic data. Part II: S-inversion: Journal of Applied Geophysics 46 235 248 doi:10.1016/S0926-9851(01)00041-6
[Google Scholar]
Zhdanov M. S. Pavlov D. Ellis R. 2002 Localized S-inversion of time domain electromagnetic data: Geophysics 67 1115 1125 doi:10.1190/1.1500372
[Google Scholar]

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Calculation of conductivity and depth correction factors for the S-layer differential transformFN1

Exploration Geophysics 39, 133 (2008); https://doi.org/10.1071/EG08014

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Article Type: Research Article

Keyword(s): TDEM, S-layer, depth, conductivity, correction factors, CDI, VTEM.

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Calculation of conductivity and depth correction factors for the S-layer differential transformFN1

Abstract

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