DOI QR코드

DOI QR Code

Analysis of Hydrocarbon Trap in the Southwestern Margin of the Ulleung Basin, East Sea

동해 울릉분지 남서주변부의 탄화수소 트랩 분석

  • Lee, Minwoo (Korea Institute of Geoscience & Mineral Resources (KIGAM)) ;
  • Kang, Moo-Hee (Korea Institute of Geoscience & Mineral Resources (KIGAM)) ;
  • Yoon, Youngho (Korea Institute of Geoscience & Mineral Resources (KIGAM)) ;
  • Yi, Bo-Yeon (Korea Institute of Geoscience & Mineral Resources (KIGAM)) ;
  • Kim, Kyong-O (Korea Institute of Geoscience & Mineral Resources (KIGAM)) ;
  • Kim, Jinho (Korea Institute of Geoscience & Mineral Resources (KIGAM)) ;
  • Park, Myong-ho (Korea National Oil Corporation (KNOC)) ;
  • Lee, Keumsuk (Korea National Oil Corporation (KNOC))
  • Received : 2015.03.18
  • Accepted : 2015.07.29
  • Published : 2015.08.28

Abstract

A commercial gas field was found in the southwestern continental shelf of the Ulleung Basin, East Sea in the late 1990s. To develop additional gas field, an exploration well was drilled through the coarse infill of submarine canyon near the gas field, but it was uneconomic to develop hydrocarbons. Using newly acquired deep seismic reflection and previous well data, we have identified additional geological structure which has hydrocarbon potentials below submarine canyons in the southwestern margin of the basin. Based on the interpretation of the deep seismic reflection and well data, the sequences of the study area can be classified into the syn-rift megasequence(MS1), post-rift megasequence(MS2), syn-compressional megasequence(MS3), and post-compressional megasequence(MS4) in relation to the tectonic events. MS1, deposited simultaneously with the basin formation before the middle Miocene, is characterized by chaotic seismic facies with low- to moderate-amplitude and low frequency reflections. MS2 comprises laterally continuous, low- to moderate-amplitude reflections, showing progradational stacking patterns due to high rates of sediment supply during basin expansion in the middle Miocene. MS3 is mainly composed of continuous reflections with high amplitude and moderate- to high-frequency which are interpreted as coarse-grained sediments. The coarse-grained sediments of MS3 sequence is widely truncated by several submarine canyons which filled with fine-grained sediment of MS4 to form a stratigraphic trap of hydrocarbon. Therefore, the reservoir and seal of the hydrocarbon trap in the study area are coarse-grained sediment of MS3 and submarine canyon filled with fine-grained sediment of MS4, respectively. A flat-spot seismic anomaly, which may indicate the presence of hydrocarbon, is observed within the stratigraphic trap.

동해 울릉분지 남서주변부는 탄화수소의 부존 가능성이 높은 대륙붕 환경으로 1990년대 말에 상업적 생산이 가능한 가스전이 발견된 바 있다. 가스전과 인접한 연구지역에서도 추가적인 가스개발을 위해 침식수로 내부의 조립질 퇴적체를 대상으로 시추가 수행되었지만 경제성이 부족한 것으로 판명되었다. 본 연구에서는 새로 취득된 탄성파 및 기존 시추 자료를 이용하여 울릉분지 남서주변부에 분포하는 침식수로 하부에 탄화수소 트랩 가능성이 있는 지질구조를 탐지하였다. 취득된 심부 탄성파 자료 및 시추자료 해석에 의하면 연구지역에 분포하는 퇴적층은 구조진화와 연계하여 열개동시성 퇴적층군(MS1), 후열개 퇴적층군(MS2), 횡압력 동시성 퇴적층군(MS3), 후횡압력 퇴적층군(MS4)으로 구분된다. 중기 마이오세 이전에 분지형성과 동시에 퇴적된 MS1은 주로 중-저진폭, 저주파수의 캐오틱 음향특성을 나타낸다. 중기 마이오세 동안 분지가 확장되며 다량의 퇴적물이 유입된 MS2는 중-저진폭의 음향특성과 함께 연속성이 양호하며 전진퇴적 양상을 나타낸다. MS3은 고진폭 및 중-고주파수의 연속성이 양호한 반사면을 나타내는데 이는 조립질 퇴적층으로 해석된다. 조립질 퇴적물이 우세한 MS3는 침식수로에 의해 광역적으로 삭박되었으며 침식수로 내부에는 MS4의 세립질 퇴적물이 충전되어 층서트랩을 형성한다. 따라서 연구지역의 트랩 구조는 MS3의 조립질 퇴적층이 저류층을 형성하며 MS4의 세립질 퇴적물로 충전된 침식수로가 덮개암으로 작용하는 층서 트랩으로 트랩 구조 내부에서는 탄화수소 부존을 지시하는 flat-spot 탄성파 이상대가 발달한다.

Keywords

References

  1. Catuneanu, O. (2006) Principles of Sequence Stratigraphy. Elsevier Science Ltd., Amsterdam, 375p.
  2. Choi, D.L. (1998) Seismic Sequence Stratigraphy in the Southwestern Margin of the Ulleung Basin, East Sea. Korean Jour. of Petrol. Geol., v.6, p.1-7.
  3. Chough, S.K. (1983) Marine Geology of Korean Seas. International Human Resources Development Corporation, Boston, 157p.
  4. Chough, S.K. and Barg, E. (1987) Tectonic history of Ulleung Basin margin, East Sea(Sea of Japan). Geology, v.15, p.45-48. https://doi.org/10.1130/0091-7613(1987)15<45:THOUBM>2.0.CO;2
  5. Emery, K.O. and Niino Hiroshi (1968) Stratigraphy and petroleum prospects of Korea Straits and the East China sea. CCOP Bulletin, v.1, p.13-27.
  6. Galloway, W.E. (1989) Genetic stratigraphic sequences in basin anlysis I: Architecture and genesis of floodingsurface bounded depositional units. AAPG Bulletin, v.73, p.125-142.
  7. Galloway, W.E. (2004) Accommodation and the sequence stratigraphic paradigm. Reservoir, Canadian Society of Petroleum Geologists, v.31, p.9-10.
  8. Haq, B.U., Hardenbol, J. and Vail, P.R. (1987) Chronology of fluctuating sea levels since the Triassic. Science, v.235, p.1156-1167. https://doi.org/10.1126/science.235.4793.1156
  9. Hilchie, D.W. (1978). Applied openhole log interpretation. Golden (CO), Douglas W. Hilchie Inc., 300 pp.
  10. Inoue, E. (1982) Geological problems on Cretaceous and Tertiary rocks around Tsushima-Korea Straits; UN. ESCAP CCOP Technical Bulletin, v.15, p.85-121.
  11. Juhasz, G., Pogacsas, G., Magyar, I. and Hayalyak, P. (2013) The Alpar canyon system in the Pannonian Basin, Hungary-its morphology, infill and development. Global and Planetary Change, v.103, p.174-192. https://doi.org/10.1016/j.gloplacha.2012.10.003
  12. Kang, M.H., Koo, N.H., Kim, S.P., Kim, S.J., Kim, J.H., Sunwoo, D., Lee, H.Y., Jang S.H., Choi, H.S., Han, H.C., Kim, K.O., Kim, B.Y., Kim, W.S., Kim, J.H., Cheong, S., Yoon, Y.H. and Yi, B.Y. (2013) 2012 Seismic Survey in the Ulleung Basin for $CO_2$ Offshore Geological Sequestration Storage. 148p.
  13. KIER(Korea Institute of Energy and Resources) (1982) Petroleum Resources Potential in Continental shelf of Korea. 342p.
  14. Kim, H.J., Lee, G.H., Jou, H.T., Cho, H.M., Yoo, H.S., Park, G.T. and Kim, J.S. (2007) Evolution of the eastern margin of Korea: constraints on the opening of the East Sea(Japan Sea). Tectonophysics, v.436, p.37-55. https://doi.org/10.1016/j.tecto.2007.02.014
  15. Lee, G.H., Kim, B.Y., Chang, S.J. and Kim, H.J. (2004) Timing of trap formation in the southwestern margin of the Ulleung Basin, East Sea(Japan Sea) and implications for hydrocarbon accumulations. Geoscience Journal, v.8, p.369-380. https://doi.org/10.1007/BF02910473
  16. Lee, G.H., Kim, H.J., Han, S.J. and Kim, D.C. (2001) Seismic stratigraphy of the deep Ulleung Basin in the East Sea(Japan Sea) back-arc basin. Marine and Petroleum Geology, v.18, p.615-634. https://doi.org/10.1016/S0264-8172(01)00016-2
  17. Lee, G.H., Lee, G.S. and Yoon, Y.H. (2009) Distribution of faults and tectonic activity along the southwestern margin of the Ulleung Basin, East sea. Korea Meteorological Administration, 55p.
  18. Lee, G.H. and Suk, B.C. (1998) Latest Neogene-Quaternary seismic stratigraphy of the Ulleung Basin, East Sea(Sea of Japan). Marine Geology, v.146, p.205-224. https://doi.org/10.1016/S0025-3227(97)00123-0
  19. Lee, G.H., Yoon, Y.H., Nam, B.H., Lim, H.H., Kim, Y.S., Kim, H.J. and Lee, K.S. (2011) Structural evolution of the southwestern margin of the Ulleung Basin, East Sea(Japan Sea) and tectonic implications. Tectonophysics, v.502, p.293-307. https://doi.org/10.1016/j.tecto.2011.01.015
  20. Li, M. and Zhao, Y. (2014) Geophysical Exploration Technology: Applications in Lithological and Stratigraphic Reservoirs. Elservier Science Ltd., Boston, 449p.
  21. Madof, A.S., Christie-Blick, N. and Anders, M.H. (2009) Stratigraphic controls on a salt-withdrawal intraslope minibasin, north-central Green Canyon, Gulf of Mexico: Implications for misinterpreting sea level change. AAPG Bulletin, v.93, p.535-561. https://doi.org/10.1306/12220808082
  22. MicroStrat. (1993) Integrated seismic sequence stratigraphic analysis of the Gorae-1 well, 52p.
  23. Mitchum, Jr., R.M., Vail, P.R. and Sangree, J.B. (1977) Stratigraphic interpretation of seismic reflection patterns in depositional sequences. In Payton, C.E.(ed.), Seismic Stratigraphy-Applications to Hydrocarbon Exploration. AAPG Memoir 26, p. 117-133.
  24. Park, K.S. (1990) The seismic stratigraphy, structure and hydrocarbon potential of the Korea Strait, Unpublished Ph.D. Thesis, Imperial University, 431p.
  25. Park, K.S. (1992) Geologic Structure and seismic stratigraphy of the Southern Part of Ulleung Basin. In Chough, S.K.(ed.), Sedimentary Basins in the Korean Peninsula and adjacent Seas. Special Publication of the Korean Sedimentary Research Group(KSRG), p.40-59.
  26. Park, S.J. (1998) Stratal patterns in the Southwestern margin of Ulleung back-arc basin: a sequence stratigraphic analysis. Unpublished Ph. D thesis, Seoul National University, 176p.
  27. Posamentier, H.W. and Kolla, V. (2003) Seismic geomorphology and stratigraphy of depositional elements in deep-water settings. Journal of Sedimentary Research, v.73, p.367-388. https://doi.org/10.1306/111302730367
  28. Sangree, J.B. and Widmier, J.M. (1978) Seismic stratigraphy and Global changes of Sea Level, Part 9: Seismic Interpretation of Clastic Depositional Facies. The American Association of Petroleum Geologists Bulletin, v.62, p.752-771.
  29. Schlager, W. (1991) Depositional bias and environmental change-important factors in sequence stratigraphy. Sedimentary Geology, v.70, p.109-130. https://doi.org/10.1016/0037-0738(91)90138-4
  30. Selley, R.C. and Sonnenberg, S.A. (2014) Elements of Petroleum Geology. Amsterdam: Academic Press.
  31. Shanmugam, G. (2000) 50 years of the turbidite paradigm (1950s-1990s): deep-water processes and facies models-a critical perspective. Marine and Petroleum Geology, v.17, p.285-342. https://doi.org/10.1016/S0264-8172(99)00011-2
  32. Shin, K.S. (2000) Sequence Stratigraphy of Tertiary Sedimentary Sequences in the SW Margin of Ulleng Basin, East Sea. Unpublished Ph.D. Thesis, Yonsei University, 161p.
  33. Shin, K.S., Yu, K.M., Kim, K.D. and Um, C.L. (1997) 3D Seismic Data Interpretation of the Gorae II Area, Block VI-1, Offsohre Southeast Korea. Korean Jour. of Petrol. Geol., v.5, p.27-35.
  34. Shinn, Y.J., Yoo, D.G., Hwang, S.H., Park, Y.C. and Huh, D.G. (2012) A Preliminary Screening of $CO_2$ Geological Storage in Ulleung Basin, Korea. The Korean Society of Mineral and Energy Resources Engineers, v.49, p.47-58.
  35. Sneider, J.S. (2003) Shelf margin deltas and associated deepwater deposits: Implications on reservoir distribution and hydrocarbon entrapment, Block VI-1, Ulleung Basin, East Sea, South Korea. Shelf Margin Deltas and Linked Down Slope Petroleum Systems: Global Significance and Future Exploration Potential, Proceedings of GCSSEPM 23rd Annual Research Conference, Not Paginaed.
  36. Tamaki, K., Suyehiro, K., Allen, J., Ingle, J.C.Jr. and Pisciotto, K.A. (1992) Tectonic synthesis and implications of Japan Sea ODP drilling. Proceedings of the Ocean Drilling Program (part 2), 1333-1348.
  37. Yoon, S.H. (1994) The eastern continental margin of Korea's seismic stratigraphy, geologic structure & tectonic evolution. Unpublished Ph.D. Thesis, Seoul National University, 136p.
  38. Yoon, S.H., Chough, S.K. and Park, S.J. (2003) Sequence model and its application to a Miocene shelf-slope system in the tectonically active Ulleung Basin margin, East Sea(Sea of Japan). Marine and Petroleum Geology, v.20, p.1089-1103. https://doi.org/10.1016/j.marpetgeo.2003.08.001
  39. Yoon, S.H., Park, S.J. and Chough, S.K. (1997) Multi-variable sequence stratigraphic model and its application to shelf-slope system of the southwestern Ulleung Basin Margin. Korean Jour. of Petrol. Geol., v.5, p.36-47.
  40. Yoon, S.H., Park, S.J. and Chough, S.K. (1997b) Western boundary fault systems of Ulleung Back-arc Basin : further evidence of pull-apart opening. Geoscience Journal, v.1, p.75-88. https://doi.org/10.1007/BF02910479
  41. Yoon, S.H., Park, S.J. and Chough, S.K. (2002) Evolution of sedimentary basin in the southwestern Ulleung Basin margin: Sequence stratigraphy and geologic structures. Geosciences Journal, v.6, p.149-159. https://doi.org/10.1007/BF03028286