Browse > Article
http://dx.doi.org/10.7582/GGE.2012.15.2.075

Computation of Apparent Resistivity from Marine Controlled-source Electromagnetic Data for Identifying the Geometric Distribution of Gas Hydrate  

Noh, Kyu-Bo (Dept. of Natural Resources and Geoenvironmental Engineering, Hanyang University)
Kang, Seo-Gi (Dept. of Natural Resources and Geoenvironmental Engineering, Hanyang University)
Seol, Soon-Jee (Dept. of Natural Resources and Geoenvironmental Engineering, Hanyang University)
Byun, Joong-Moo (Dept. of Natural Resources and Geoenvironmental Engineering, Hanyang University)
Publication Information
Geophysics and Geophysical Exploration / v.15, no.2, 2012 , pp. 75-84 More about this Journal
Abstract
The sea layer in marine Controlled-Source Electromagnetic (mCSEM) survey changes the conventional definition of apparent resistivity which is used in the land CSEM survey. Thus, the development of a new algorithm, which computes apparent resistivity for mCSEM survey, can be an initiative of mCSEM data interpretation. First, we compared and analyzed electromagnetic responses of the 1D stratified gas hydrate model and the half-space model below the sea layer. Amplitude and phase components showed proper results for computing apparent resistivity than real and imaginary components. Next, the amplitude component is more sensitive to the subsurface resistivity than the phase component in far offset range and vice versa. We suggested the induction number as a selection criteria of amplitude or phase component to calculate apparent resistivity. Based on our study, we have developed a numerical algorithm, which computes appropriate apparent resistivity corresponding to measured mCSEM data using grid search method. In addition, we verified the validity of the developed algorithm by applying it to the stratified gas hydrate models with various model parameters. Finally, by constructing apparent resistivity pseudo-section from the mCSEM responses with 2D numerical models simulating gas hydrate deposits in the Ulleung Basin, we confirmed that the apparent resistivity can provide the information on the geometric distribution of the gas hydrate deposit.
Keywords
mCSEM; apparent resistivity; gas hydrate; geometrical distribution;
Citations & Related Records
Times Cited By KSCI : 1  (Citation Analysis)
연도 인용수 순위
1 Weitemeyer, K., Gao, G., Constable, S., and Alumbaugh, D., 2010, The practical application of 2D inversion to marine controlled-source electromagnetic data, Geoeophysics, 75(6), F199-F210.   DOI
2 Das, U. C., 1995, Apparent resistivity curves in controlled-source electromagnetic sounding directly reflecting true resistivities in a layered earth, Geophysics, 60(1), 53-60.   DOI
3 Hyndman, R. D., Yuan, T., and Morgn, K., 1999, The concentration of deep sea hydrates from down-hole electrical resistivity logs and laboratory data, Earth Planet Science Letter, 172, 167-177.   DOI
4 Kang, S., Seol, S. J., and Byun, J., 2012, A feasibility study of $CO_2$ sequestration monitoring using the mCSEM method at a deep brine aquifer in a shallow sea, Geophysics, 77, E117-E126.   DOI
5 Kaufman, A. A., 1994, Geophysical field theory and method, Part C, Academic Press, Inc. 41-57.
6 Lee, K. H., 2009, Personal communication.
7 Lee, K. H., Jang, H., Jang, H., and Kim, H. J., 2011, Sensitivity analysis of marine controlled-source electromagnetic methods to a shallow gas-hydrate layer with 1D forward modeling, Geosciences Journal, 15(3), 297-303.   DOI
8 McNeill, D., 1980, Electromagnetic terrain conductivity measurements at low induction numbers, Technical Note TN-6, Geonics Ltd, Toronto
9 Ryu, J., Morrison, H., and Ward, S., 1970, Electromagnetic fields about a loop source of current, Geophysics, 35, 862-896.   DOI
10 Spies, B. R. and Frischknecht, F. C., 1991, Eletromagnetic Sounding, in Nabighian, M. N., Ed., Electromagnetics in Applied Geophysics, Vol. III, Soc. Expl. Geophys., 285-425.
11 Weitemeyer, K., Constable, S., and Key, K., 2006, Marine EM techniques for gas-hydrate detection and hazard mitigation, The Leading Edge, 25, 629-632.   DOI
12 Weitemeyer, K., 2008, Marine Electromagnetic Methods for Gas Hydrate Characterizations, Ph. D. thesis, University of California, San Diego.
13 강동효, 유동근, 박장준, 류병재, 구남형, 김원식, 박관순, 박근필, 김지수, 2009, 동해 울릉분지의 가스하이드레이트 부존 형태, 지질학회지, 45, 143-155.
14 강서기, 설순지, 변중무, 2010, 가스하이드레이트 탐사를 위한 해저 CSEM탐사 설계변수 고찰, 한국지구시스템공학회, 47, 139-150.
15 김길영, 유동근, 류병재, 2010, 물리검층 자료를 이용한 동해 울릉분지 가스하이드레이트 함유지층의 물성특성 해석, 지질학회지, 46, 275-290.
16 유동근, 강동효, 구남형, 김원식, 김길영, 김병엽, 정순홍, 김영준, 이호영, 박근필, 이광훈, 박수철, 2008, 동해 울릉분지의 가스 하이드레이트 부존 지구물리증거, 지질학회지, 44, 645-655.
17 Constable, S., 2010, Ten years of marine CSEM for hydrocarbon exploration, Geophysics, 75(5), A67-A81.
18 설순지, 송윤호, 조성준, 손정술, 정승환, 2002, 소형루프 전자탐사법을 이용한 매설물 탐지 및 지하 전기비저항 영상화, 물리탐사, 5, 309-315.