Seismic Properties Study of Gas Hydrate in Deep Sea using Numerical Modeling Technique

수치 모델링 기술을 이용한 심해 가스 하이드레이트의 탄성파 특성 연구

  • Shin, Sung-Ryul (Korea Maritime University, Dept. of Energy & Resources Eng.) ;
  • Yeo, Eun-Min (Korea Maritime University, Dept. of Energy & Resources Eng.) ;
  • Kim, Chan-Su (Korea Maritime University, Dept. of Energy & Resources Eng.) ;
  • Park, Keun-Pil (Korea Institute of Geoscience and Mineral Resources, Petroleum & Marine Resources Div.) ;
  • Lee, Ho-Young (Korea Institute of Geoscience and Mineral Resources, Petroleum & Marine Resources Div.) ;
  • Kim, Young-Jun (Korea Institute of Geoscience and Mineral Resources, Petroleum & Marine Resources Div.)
  • 신성렬 (한국해양대학교 해양과학기술대학 해양개발공학부) ;
  • 여은민 (한국해양대학교 해양과학기술대학 해양개발공학부) ;
  • 김찬수 (한국해양대학교 해양과학기술대학 해양개발공학부) ;
  • 박근필 (한국지질자원연구원) ;
  • 이호영 (한국지질자원연구원) ;
  • 김영준 (한국지질자원연구원)
  • Published : 2006.05.31

Abstract

We had conducted a numerical modeling to investigate seismic properties of gas hydrate with field parameters acquired over the East sea in 1998. We used a 2-D staggered grid finite difference method to generate synthetic elastic seismograms for multi-channel seismic survey, OBC (Ocean Bottom Cable) survey and VCS (Vertical Cable Seismic) survey. The results of this study showed that the method using staggered grid yielded stable results and could be used to seismic imaging. We could find out the high amplitude anomaly and the phase reversal phenomenon of reflection wave at interface between the gas hydrate layer and free gas layer such a BSR (Bottom Simulating Reflector) which is the evidence for existence of gas hydrate in seismic reflection data. And we computed the reflection coefficients at the incident angles corresponding to offset distance with the synthetic seismograms. The reflection coefficients acquired from the numerical modeling were nearly consistent with the reflection coefficient computed by Shuey's equation.

References

  1. Ecker, c., 1998, Seismic charaterization of methane hydrate structure, Stanford Exploration Project (1/21/1998)
  2. K venvo1den, K. A., and Barnard, L. A., 1983, Gas hydrate of the Blake Ridge Outer Ridge, Site 533, Deep Sea Drilling Project Leg 76, In Sheridan R. E., and Gradstein F. W. et al. eds., Initial Report, DSDP 76, U.S Government Printing Office, Washington, D.C., 353-365
  3. Shuey, R. T., 1985, A simplification of Zoeppritz equations, Geophysics, 50, 609-614 https://doi.org/10.1190/1.1441936
  4. 장성형, 서상용, 류병재, 2005, 가스 하이드레이트 탄성파 자료 복소분석 해석, 한국지구시스템공학회지, 42, 180-190
  5. Makogon, Y. F., 1997, Hydrate of hydrocarbons, Peen WellPubl. Tulsa, Oklahoma, US., p.482
  6. 장성형, 서상용, 정부흥, 류병재, 1999, Geobit를 이용한 가스 하이드레이트 탐사자료 처리, 물리탐사, 2, 184-190
  7. 신창수, 박관순, 박근필, 조철현, 1993, 수치모형 프로그램에 의한 인공탄성파 합성 및 완전파형 역산연구, KR-93(T), 과학기술처
  8. Krail, P. M., 1994, Vertical cables as a subsalt imaging tool, The Leading Edge. 46, 885-887
  9. 양동우, 양승진, 1996, AVO 및 복소분석에 의한 천연가스 저류층 탐지에 관한 연구, 한국자원공학회지, 33, 340-348
  10. 허대기, 2005, 가스하이드레이트 기술개발 현황, 한국지구시스템공학회지, 42, 206-213
  11. Shipley, T. H., and Didyh, B. M., 1982, Occurrence of methan hydrates offshore southern Mexico, Initial Report, DSDP Leg 66, U.S Government Printing Office, Washington, D.C., 547-555
  12. Ostrander, W. J., 1984, Plane wave reflection coefficients for gas sands at nonnorma1 angle of incidence, Geophysics, 49, 1637-1648 https://doi.org/10.1190/1.1441571
  13. 신성렬, 신창수, 서정희, 1997, Staggered를 이용한 유한차분법 탄성파 모델링, 한국자원공학회지, 34, 168-174
  14. Zoeppritz, K., 1919, Erdbebenwellen VlIlB, On the reflection and propagation of seismic waves, Gottinger Nachrichten, I, 66-84
  15. 양승진, 서태공, 유해수, 장재경, 2000, 하이드레이트 층에서의 탄성파 AVO 특성 연구, 한국자원공학회지, 37, 213-223
  16. Andreassen, K., Hart, E. H., and MacKay, M., 1997, Amplitude versus offset modeling of the bottom simulation reflection associated with submarine gas hydrate, Marine Geology, 137, 25-40 https://doi.org/10.1016/S0025-3227(96)00076-X