Loop-loop EM Inversion for a Conducting Sphere

doi:10.12972/ksmer.2014.51.5.696

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2014 Vol.51, Issue 5 Preview Page Next Page

Research Paper

Loop-loop EM Inversion for a Conducting Sphere 구형도체에 대한 루프-루프 전자탐사 자료 역산: 정현기
Hyun-Key Jung

31 October 2014. pp. 696-704

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Abstract

The electromagnetic(EM) response of a conductive sphere excited by an alternating magnetic field has been a traditionally important problem. In this study, following the former studies, EM inversion is applied to frequency domain EM data for estimation of location, size, and electrical characteristic of a conducting sphere in a magnetic dipole field using Levenberg-Marquardt method. Earth parameters are well resolved even on 7 data points line survey with single frequency. In areal survey, single frequency survey data with many spatial measuring points shows better estimates for the all parameters than multi frequency survey data with a few measuring points. This enhanced algorithm implemented using MATLAB could be applied to airborne EM interpretation, loop-loop EM data analysis on land, and borehole 3D application. It also can be quite helpful for a realtime interpretation of fast survey application which can sweep large minefield.

Keywords

EM inversion

Conducting sphere

Frequency domain EM

고전적인 3차원 전자탐사뿐만 아니라 최근의 항공 전자탐사나 지상 다주파수 전자탐사에 있어 그 3차원 해석은 역산기술의 발전에도 불구하고 쉽지 않다. 막대한 메모리와 전산시간을 요구하는 3차원 전자탐사자료 역산 대신에 단순한 구형도체에 대해 간단한 3차원 역산을 할 수 있는 연구결과를 제공한다. Levenberg-Marquardt 알고리즘을 적용시켜 지하도체의 위치, 크기 및 전기적 물성을 최적 추정하게 되는 주파수영역 전자탐사 자료의 역문제 계산을 수행하였다. 전산 모델링 및 역산 절차는 MATLAB 환경에서 프로그래밍하였다. 이 연구결과는 항공 전자탐사, 다양한 배열의 지상 루프-루프 전자탐사, 시추공 전자탐사 등의 자료해석에 적용 가능하다. 특히 자화율/전기전도도 동시 반영의 지뢰탐지 등과 같은 UXO(Unexploded Ordnance) 탐지에 실시간 역산 활용될 수 있다.

키워드

전자탐사자료 역산

구형도체

주파수영역 전자탐사

References

Arfken, G. and Weber, H., 2012, Mathematical Methods for Physicists, Academic Press; Seventh Edition.
Best, M.E. and Shammas, B.R., 1979, “A generalized solution for a spherical conductor in a magnetic dipole,” Geophysics, Vol. 44, pp. 781-800.
Cuyt, A.A.M., Petersen, V., Verdonk, B., Waadeland, H. and Jones, W.B., 2008, Handbook of continued fractions for special functions, Springer.
Huang, H. and Won, I.J., 2001, “Inversion of Multifrequency Electromagnetic Data to a Conductive and Permeable Sphere,” Symposium on the Application of Geophysics to Engineering and Environmental Problems 2001. pp. EEM5-EEM5.
Huang, H. and Won, I. J., 2003, “Characterization of UXO-like targets using broadband electromagnetic induction sensors,” IEEE Transactions on Geoscience and Remote Sensing, Vol. 41, No. 3, pp. 652-663.
Jung, H.K. and Suh, J.H., 1985, “Frequency-domain EM response of a spherical conductor to a magnetic dipole field: Part Ⅰ. Froward problem,” Journal of the Korean Institute of Mineral and Mining Engineers, Vol. 22, No. 1, pp. 17-24.
Lee, T.J., 1984, “Inversion of transient electromagnetic data from spherical conductor,” IEEE Transactions on Geoscience and Remote Sensing, Vol. 22, pp. 14-20.
Lodha, G.S. and West, G.F., 1976, “Practical airborne EM (AEM) interpretation using a sphere model,” Geophysics, Vol. 41, pp. 1157-1169.
Rai, S.S. and Verma, S.K., 1982, “Quantitative interpretation of horizontal-loop EM measurements using a permeable sphere model,” Geophysical Prospecting, Vol. 30, pp. 486-500.
Rai, S.S., 1983, “The effect of induced multipoles on horizontal- loop EM response of a permeable conducting sphere,” Geoexploration, Vol. 21, pp. 13-18.
Wait, J.R., 1953, “A conducting permeable sphere in the presence of a coil carrying an oscillating current,” Can. J. Phys., Vol. 31, pp. 670-678.

Information

Publisher :The Korean Society of Mineral and Energy Resources Engineers
Publisher(Ko) :한국자원공학회
Journal Title :Journal of the Korean Society of Mineral and Energy Resources Engineers
Journal Title(Ko) :한국자원공학회지
Volume : 51
No :5
Pages :696-704
DOI :https://doi.org/10.12972/ksmer.2014.51.5.696

[1] Arfken, G. and Weber, H., 2012, Mathematical Methods for Physicists, Academic Press; Seventh Edition.

[2] Best, M.E. and Shammas, B.R., 1979, “A generalized solution for a spherical conductor in a magnetic dipole,” Geophysics, Vol. 44, pp. 781-800.

[3] Cuyt, A.A.M., Petersen, V., Verdonk, B., Waadeland, H. and Jones, W.B., 2008, Handbook of continued fractions for special functions, Springer.

[4] Huang, H. and Won, I.J., 2001, “Inversion of Multifrequency Electromagnetic Data to a Conductive and Permeable Sphere,” Symposium on the Application of Geophysics to Engineering and Environmental Problems 2001. pp. EEM5-EEM5.

[5] Huang, H. and Won, I. J., 2003, “Characterization of UXO-like targets using broadband electromagnetic induction sensors,” IEEE Transactions on Geoscience and Remote Sensing, Vol. 41, No. 3, pp. 652-663.

[6] Jung, H.K. and Suh, J.H., 1985, “Frequency-domain EM response of a spherical conductor to a magnetic dipole field: Part Ⅰ. Froward problem,” Journal of the Korean Institute of Mineral and Mining Engineers, Vol. 22, No. 1, pp. 17-24.

[7] Lee, T.J., 1984, “Inversion of transient electromagnetic data from spherical conductor,” IEEE Transactions on Geoscience and Remote Sensing, Vol. 22, pp. 14-20.

[8] Lodha, G.S. and West, G.F., 1976, “Practical airborne EM (AEM) interpretation using a sphere model,” Geophysics, Vol. 41, pp. 1157-1169.

[9] Rai, S.S. and Verma, S.K., 1982, “Quantitative interpretation of horizontal-loop EM measurements using a permeable sphere model,” Geophysical Prospecting, Vol. 30, pp. 486-500.

[10] Rai, S.S., 1983, “The effect of induced multipoles on horizontal- loop EM response of a permeable conducting sphere,” Geoexploration, Vol. 21, pp. 13-18.

[11] Wait, J.R., 1953, “A conducting permeable sphere in the presence of a coil carrying an oscillating current,” Can. J. Phys., Vol. 31, pp. 670-678.

Journal of the Korean Society of Mineral and Energy Resources Engineers ISSN:2288-0291(Print) 2288-2790(Online) 한국자원공학회지

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