Resistivity Imaging by Time Domain Electromagnetic Migration (TDEMM)

Zhdanov, Michael S.; Traynin, Peter; Portniaguine, Oleg

doi:10.1071/eg995186

Cited by 25 publications

(6 citation statements)

References 2 publications

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“…Solution of this problem is important for many practical applications ranging from mineral exploration to waste and building site characterization. In the papers (Zhdanov et al, 1995) and (Zhdanov et al, 1996) and the references therein we have developed a novel approach to EM imaging based on the notion of EM migration. The method includes downward continuation of the observed field or one of its components in reverse time and application of the corresponding imaging conditions.…”

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confidence: 99%

Migration versus Inversion in Electromagnetic Imaging Technique

Zhdanov

Traynin

1997

J. geomagn. geoelec

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One of the most challenging problems in electromagnetic (EM) geophysical methods is developing fast and stable methods of imaging inhomogeneous underground structures using EM data. In our previous publications we developed a novel approach to this problem, using EM migration.In this paper we demonstrate that there is a very close connection between the method of EM migration and the solution of the conventional EM inverse problem. Actually, we show that migration is an approximate inversion. It realizes the first iteration in the inversion algorithm, based on the minimization of the residual field energy flow through the profile of observations. This new theoretical result opens a way for formulating a new imaging condition. We compare this new imaging condition with the traditional one, obtained for simplified geoelectrical models of the subsurface structures.This result also leads to the construction of a solution of the inverse EM problem, based on iterative EM migration in the frequency domain, and gradient (or conjugate gradient) search for the optimal geoelectrical model. However, the authors have found that in the framework of this method, even the first iteration, based on the migration of the residual field, generates a reasonable geoelectrical image of the subsurface structure. IntroductionOne of the most challenging problems in electromagnetic (EM) geophysical methods is developing fast and stable methods of imaging inhomogeneous underground structures using EM data. Solution of this problem is important for many practical applications ranging from mineral exploration to waste and building site characterization. In the papers (Zhdanov et al., 1995) and (Zhdanov et al., 1996) and the references therein we have developed a novel approach to EM imaging based on the notion of EM migration. The method includes downward continuation of the observed field or one of its components in reverse time and application of the corresponding imaging conditions. However, until recently the relationship between EM migration imaging and traditional EM inversion have remained unexplored. The conventional EM inversion means a method which predicts the geoelectrical model generating the theoretical data closed to observations. The EM migration introduced in our previous publications constructed an image of subsurface geoelectrical structures, and there was no guarantee this image, if included in a geoelectrical model, would give rise to theoretical EM fields that matched those observed. Meanwhile, Tarantola (1987) demonstrated that seismic wave migration, which was the prototype for EM migration, can be treated exactly as the first iteration in some general wave inversion scheme. In this paper we formulate an important new result: EM migration, as the solution of the boundary value problem for the adjoint Maxwell's equation in frequency domain, can be clearly associated with the inverse problem solution. In other words, we prove that a geoelectrical model constructed on the basis of migration images would actually generat...

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confidence: 99%

Migration versus Inversion in Electromagnetic Imaging Technique

Zhdanov

Traynin

1997

J. geomagn. geoelec

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“…The streamer system has the potential of reducing acquisition cost and providing denser receiver spacing. The dense receiver spacing is crucial for many techniques such as CSEM migration (Zhdanov et al, 1995(Zhdanov et al, , 1996Zhdanov and Traynin, 1997), up-down decomposition, and CSEM interferometry (Wapenaar et al, 2008;Fan et al, 2009;Hunziker et al, 2009Hunziker et al, , 2010. One drawback, however, is the bigger loss of energy in the sea water because the source and receiver are near the sea surface.…”

Section: Shallow Sources and Receiversmentioning

confidence: 99%

Increasing the sensitivity of controlled-source electromagnetics with synthetic aperture

et al. 2012

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Controlled-source electromagnetics (CSEM) has been used as a derisking tool in the hydrocarbon exploration industry. We apply the concept of synthetic aperture to the lowfrequency electromagnetic field in CSEM. Synthetic aperture sources have been used in radar imaging for many years. Using the synthetic aperture concept, big synthetic sources can be constructed by adding the response to small sources (building blocks) in different ways, and consequently, big sources with different radiation patterns can be created. We show that the detectability of hydrocarbons is significantly enhanced by applying synthetic aperture to CSEM data. More challenging targets such as deep reservoirs (4 km below sea floor) can be detected. The synthetic aperture technique also increases the sensitivity of the field to subsurface targets in the towing streamer acquisition. We also show that a pseudovertical source (orthogonally distributed dipole pairs) can be constructed synthetically, and that the detection capability of this pseudovertical source is increased by applying field steering. The synthetic aperture concept opens a new line of research in CSEM, with the freedom to design suitable synthetic aperture sources for a given purpose.

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“…It has been experienced nearly three decades since Zhdanov [1,2] and others proposed the theory of migration imaging of electromagnetic data. The theory becomes more and more mature, and the technique becomes more abundant.…”

Section: Introductionmentioning

confidence: 99%

Time domain electromagnetic migration imaging

Wang¹,

Yuan²,

Di³

et al. 2016

Proceedings of the 7th International Conference on Environment and Engineering Geophysics &Amp; Summit Forum of Chinese Academy

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Abstract-This article is about the study of time domain electromagnetic data migration imaging. First, based on the electromagnetic diffusion theory and the boundary conditions, we deduce the analytical formula of electromagnetic migration field. Then, we complete the calculation of electromagnetic migration field filter by electromagnetic migration field theory in frequency domain. The analytical electromagnetic migration filter is discretized to achieve electromagnetic numerical migration filter to make it able to be applied into practical discrete sampling. By analyzing the error caused by of discretization procedure according to the theory of electromagnetic migration filter, we deduce discretization error correction formula. Moreover, we study and realize the transform from time domain to frequency domain, and make it able to be used in time domain electromagnetic migration imaging. In order to test migration imaging technology, whole space 2D or 3D geoelectric models are built with the transmiter-receiver distance varying from near field to several thousand kilometers. Using the technology presented by this paper to the numeric data, the reasonable position of underground exploration body can be recovered. Finally, we deduce 2D migration field analytical formula in time domain and discretize it, then complete the numeric calculation in time domain directly. We analyze the kernel function of time domain electromagnetic migration filter and its influence factors, and test the effect of time domain migration field imaging by several simple geoelectric models.

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Resistivity Imaging by Time Domain Electromagnetic Migration (TDEMM)

Cited by 25 publications

References 2 publications

Migration versus Inversion in Electromagnetic Imaging Technique

Migration versus Inversion in Electromagnetic Imaging Technique

Increasing the sensitivity of controlled-source electromagnetics with synthetic aperture

Time domain electromagnetic migration imaging

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