An Investigation in Operating and Design Parameters for Gas Hydrate Exploration using Marine CSEM

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2010 Vol.47, Issue 2 Preview Page Next Page

An Investigation in Operating and Design Parameters for Gas Hydrate Exploration using Marine CSEM 가스 하이드레이트 탐사를 위한 해저 CSEM탐사 설계변수 고찰: 강서기 , 설순지 , 변중무
Seogi Kang, Soon Jee Seol and Joongmoo Byun

30 April 2010. pp. 139-150

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Abstract

In this paper, we have investigated general operating and design parameters of marine controlled source electromagnetic (CSEM) survey for gas hydrate detection. Numerical forward modelings were executed in terms of frequency and source-receiver offset with variable resistivity of depth to the gas hydrate layer. To estimate the detectability of gas hydrate layer, the total electric field of the gas hydrate model was normalized by that of the half-space model response. As a result, we confirmed that as the depth to the gas hydrate layer increases, the domain of transmission frequency and source-receiver offset with the maximum detectability moves to the area of low frequency band and far offset range. On the basis of this result, we propose operating and design parameters of Marine CSEM survey - source-receiver offset, source height from seafloor and transmission frequency - at the East sea where the existence of gas hydrate has been confirmed. In addition, to analyze characteristics of air wave, we carried out numerical modelings with variable sea depth.

Keywords

Marine CSEM

Gas hydrate

Detectability

Operating and design parameters

Air wave

이 연구에서는 해저 CSEM을 이용한 일반적인 가스 하이드레이트 탐사시의 설계변수에 대해서 고찰하였다. 이를 위해 가스 하이드레이트층의 전기비저항과 부존 심도를 변화시켜가며 송신주파수와 송수신기 간격에 대하여 수치모형반응 계산을 시행하여 층의 탐지가능성을 조사하였다. 탐지가능성을 도출하기 위해 사용한 방법은 정규화로서 가스 하이드레이트층이 있는 모형의 반응을 가스 하이드레이트층이 없는 모형(half-space)의 반응으로 나눈 값에 상용로그를 취한 값을 사용하였다. 그 결과 층의 부존 심도가 깊어짐에 따라 탐지가능성을 갖는 영역이 저주파수 대역의 원거리 송수신기 간격으로 이동하며, 층의 전기비저항이 증가함에 따라 광대역의 큰 탐지가능성을 갖게 되는 것을 확인하였다. 이러한 연구결과를 토대로 가스 하이드레이트의 부존이 확인된 동해 울릉분지에서의 해저 CSEM탐사의 설계변수를 제안하였다. 이때 제안한 변수들은 해저면으로부터의 송신원 높이, 송신주파수, 송수신기 간격이다. 또한, 해수의 심도를 변화시켜 가며 air wave의 특성을 정성적, 정량적으로 분석하였다.

키워드

해저 CSEM탐사

가스 하이드레이트

탐지가능성

설계변수

air wave

References

김희준, 한누리, 최지향, 남명진, 송윤호, 서정희, 2006, “탄화수소 탐지를 위한 해양 인공송신원 전자탐사,” 물리탐사, Vol, 9, No. 2, pp. 163-170.
송윤호, 김희준, 설순지, 2007, “Marine CSEM의 최근 기술 개발 및 적용 사례,” 한국지구․물리탐사학회 특별심포지엄, 한양대학교, 서울, 12월 5일, pp. 95-108.
Constable, S. C., 2006, “Marine electromagnetic methods – A new tool for offshore exploration,” The Leading Edge, Vol. 25, No. 3, pp. 438-444.
Constable, S. C. and Weiss, C. J., 2006, “Mapping thing resistors and hydrocarbons with marine EM methods: Insights from 1D modeling,” Geophysics, Vol. 71, No. 2, pp. 43-51.
Edwards, R. N., 1997, “On the resource evaluation of marine gas hydrate deposits using sea-floor transcient electric dipole-dipole methods,” Geophysics, Vol. 62, No. 1, pp. 63-74.
Field, E. and Kvenvolden, A., 1985, “Gas hydrate on the northern California continental margin,” Geology, Vol. 13, No. 7, pp. 517-520.
Kim, G. Y., Yoo, D. G., Kim, W. S., Lee, H. Y. and Park, K. I., 2008, “Physical properties of gas hydrates-bearing sediments in the Uleung Basin,” Proc. of the 6th International Conference on Gas Hydrates, Vancouver, British Columbia, CANADA, July 6-10.
Lee, J. H., Baek, Y. S., Ryu, J., Riedel, M., and Hyndman, R. D., 2005, “A seismic Survey to Detect Natural Gas Hydrate in the East Sea of Korea,” Marine Geophysical Researches, Vol. 26, No. 1, pp. 51-58.
Lee, K. H., 2009, Personal communication. Lien, M. and Mannseth, T., 2008, “Sensitivity study of marine CSEM data for reservoir production monitoring,” Geophysics, Vol. 73, No. 4, pp. 151-163.
MacGregor, L., Andreis, D., Tomlinson. J. and Barker, N., 2006, “Controlled-source electromagnetic imaging on the Nuggets-1 reservoir,” The Leading Edge, Vol. 25, No. 8, pp. 948-992.
Orage, A., Key, K. and Constable, S. C., 2009, “The feasibility of reservoir monitoring using time-lapse marine CSEM,” Geophysics, Vol. 74, No. 2, pp. 21-29.
Tr´ehu, A., Torres, M., Bohrmann, G., and Colwell, F., 2006, “Leg 204 Synthesis:Gas hydrate distribution and dynamics in the Central Cascadia accretionarycomplex,” In Proceedings of the Ocean Drilling Program, Sceintific Results, Vol. 204, pp. 1-40.
Um, E. S. and Alumbaugh, D. L., 2007, “On the physics of the marine controlled-source electromagnetic method,” Geophysics, Vol. 72, No. 2, pp. 13-26.
Weitemeyer, K., 2008, “Marine Electromagnetic Methods for Gas Hydrate Characterization,” MS thesis, University of California, San Diego.

Information

Publisher :The Korean Society of Mineral and Energy Resources Engineers
Publisher(Ko) :한국자원공학회
Journal Title :Journal of the Korean Society for Geosystem Engineering
Journal Title(Ko) :한국지구시스템공학회지
Volume : 47
No :2
Pages :139-150

[1] 김희준, 한누리, 최지향, 남명진, 송윤호, 서정희, 2006, “탄화수소 탐지를 위한 해양 인공송신원 전자탐사,” 물리탐사, Vol, 9, No. 2, pp. 163-170.

[2] 송윤호, 김희준, 설순지, 2007, “Marine CSEM의 최근 기술 개발 및 적용 사례,” 한국지구․물리탐사학회 특별심포지엄, 한양대학교, 서울, 12월 5일, pp. 95-108.

[3] Constable, S. C., 2006, “Marine electromagnetic methods – A new tool for offshore exploration,” The Leading Edge, Vol. 25, No. 3, pp. 438-444.

[4] Constable, S. C. and Weiss, C. J., 2006, “Mapping thing resistors and hydrocarbons with marine EM methods: Insights from 1D modeling,” Geophysics, Vol. 71, No. 2, pp. 43-51.

[5] Edwards, R. N., 1997, “On the resource evaluation of marine gas hydrate deposits using sea-floor transcient electric dipole-dipole methods,” Geophysics, Vol. 62, No. 1, pp. 63-74.

[6] Field, E. and Kvenvolden, A., 1985, “Gas hydrate on the northern California continental margin,” Geology, Vol. 13, No. 7, pp. 517-520.

[7] Kim, G. Y., Yoo, D. G., Kim, W. S., Lee, H. Y. and Park, K. I., 2008, “Physical properties of gas hydrates-bearing sediments in the Uleung Basin,” Proc. of the 6th International Conference on Gas Hydrates, Vancouver, British Columbia, CANADA, July 6-10.

[8] Lee, J. H., Baek, Y. S., Ryu, J., Riedel, M., and Hyndman, R. D., 2005, “A seismic Survey to Detect Natural Gas Hydrate in the East Sea of Korea,” Marine Geophysical Researches, Vol. 26, No. 1, pp. 51-58.

[9] Lee, K. H., 2009, Personal communication. Lien, M. and Mannseth, T., 2008, “Sensitivity study of marine CSEM data for reservoir production monitoring,” Geophysics, Vol. 73, No. 4, pp. 151-163.

[10] MacGregor, L., Andreis, D., Tomlinson. J. and Barker, N., 2006, “Controlled-source electromagnetic imaging on the Nuggets-1 reservoir,” The Leading Edge, Vol. 25, No. 8, pp. 948-992.

[11] Orage, A., Key, K. and Constable, S. C., 2009, “The feasibility of reservoir monitoring using time-lapse marine CSEM,” Geophysics, Vol. 74, No. 2, pp. 21-29.

[12] Tr´ehu, A., Torres, M., Bohrmann, G., and Colwell, F., 2006, “Leg 204 Synthesis:Gas hydrate distribution and dynamics in the Central Cascadia accretionarycomplex,” In Proceedings of the Ocean Drilling Program, Sceintific Results, Vol. 204, pp. 1-40.

[13] Um, E. S. and Alumbaugh, D. L., 2007, “On the physics of the marine controlled-source electromagnetic method,” Geophysics, Vol. 72, No. 2, pp. 13-26.

[14] Weitemeyer, K., 2008, “Marine Electromagnetic Methods for Gas Hydrate Characterization,” MS thesis, University of California, San Diego.

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

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