Journal of Marine Sciences ›› 2014, Vol. 32 ›› Issue (4): 19-26.DOI: 10.3969/j.issn.1001-909X.2014.04.003

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Seismic reflecting characteristics of fluid and its effect on gas hydrate distribution in the Shenhu Area, South China Sea

YANG Rui1,2,3,4, YAN Pin*1, WU Neng-you2,3, QIAO Shao-hua2,3,4, SU Ming2,3, LIANG Jin-qiang5, GUO Pan6, HUO Yuan-yuan7   

  1. 1. Key Laboratory of Marginal Sea Geology of Chinese Academy of Sciences, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China;
    2. Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China;
    3. Key Laboratory of Gas Hydrate, Chinese Academy of Sciences, Guangzhou 510640, China;
    4. University of the Chinese Academy of Sciences, Beijing 100049, China;
    5. Guangzhou Marine Geological Survey, Guangzhou 510075, China;
    6. Shanxi Tiandi Geological Co., Ltd, Xi'an 710054, China;
    7. Research Institute of Exploration and Development, Northern China Branch, Sinopec, Zhengzhou 450000, China
  • Received:2013-11-27 Revised:2014-10-14 Online:2014-12-15 Published:2022-11-25

Abstract: The distribution of gas hydrate is affected greatly by the migration of gas fluid. The leakage of gas fluid is common in the slope of northern South China Sea, especially in the Baiyun Sag in the Pearl River Mouth Basin, which implies good prospect of gas hydrate occurrence. According to high resolution seismic data about the Shenhu Area, large numbers of fuzzy zones with different morphological characteristics were recognized. They were considered to be main channel of free gas and could be classified into two types: corolliform and dome-form. The existence of fuzzy zones implied that there was a good condition for the migration of gas hydrate in this area, which could provide a vertical channel for free gas migration. Drilling results showed that gas hydrate zones were related to special distribution of fuzzy zones. The corolliform fuzzy zones connected with a set of middle size faults, which promoted the free gas moving to the flank area. The top might connect the small crack with which the free gas could move upwards to the gas hydrate stability zone to form gas hydrate. The top of dome-form fuzzy zones might connect to seafloor through the gas fluid crack. This kind structure could cause the free gas escape and therefore could not form the gas hydrate. This classification method could provide a new indicator about gas hydrate distribution.

Key words: Shenhu Area, fluid migration, fuzzy zone on seismic profile, corolliform, dome-form, gas hydrate

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