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现代地质 ›› 2006, Vol. 20 ›› Issue (1): 123-129.

• 天然气水合物 • 上一篇    下一篇

南海北部陆坡天然气水合物的地震速度研究

梁劲1,王宏斌1,2,郭依群1,3    

  1. 1广州海洋地质调查局,广东广州510760;2中国地质大学地球物理与信息技术学院,北京100083;
    3中国地质大学海洋学院,北京100083
  • 收稿日期:2005-07-19 修回日期:2005-12-30 出版日期:2006-01-20 发布日期:2006-01-20
  • 作者简介:梁劲,男,高级工程师,1971年出生,应用地球物理专业,主要从事天然气水合物调查与研究工作。
  • 基金资助:

    国家“天然气水合物资源综合评价及勘探开发战略研究”专项项目(GZH200200203-03)

Study of Seismic Velocity about Gas Hydrates in the Northern Slope of the South China Sea

LIANG Jin1,WANG Hong-bin1,2,GUO Yi-qun1,3   

  1. 1Guangzhou Marine Geological Survey, Guangzhou, Guangdong510760, China;
    2School of Geophysics and Information Technology, China University of Geosciences, Beijing100083, China;
    3School of Marine Geosciences, China University of Geosciences, Beijing100083, China
  • Received:2005-07-19 Revised:2005-12-30 Online:2006-01-20 Published:2006-01-20

摘要:

采用Dix公式法和速度反演法分别对南海北部陆坡测线A和B的层速度及纵波速度进行计算,结合BSR、振幅空白带以及波形极性反转等多种水合物赋存信息的分析,对水合物成矿带的速度特征进行了综合研究。结果表明:低速背景中的高速异常,是天然气水合物赋存的重要特征;高速异常体一般呈平行于海底的带状分布;在高速异常体的内部,速度也是不断变化的,一般在异常体的中心速度最高,由中心到边缘速度逐渐降低,反映在水合物矿带内部,水合物饱和度由矿体中心向边缘逐渐降低的特征。研究结果表明高精度速度分析不仅可以帮助寻找水合物矿点,还可以进一步判定水合物的富集层位。

关键词: 南海北部陆坡, 天然气水合物, 地震速度, Dix公式, 速度反演

Abstract:

The interval velocity and P velocity of seismic profiles A and B in the northern slope of the South China Sea were calculated by the methods of Dix equation and velocity inversion. The velocity characteristics of the gas hydrate bed were studied in detail based on the calculated results and the information,including BSR, amplitude blanking and polarity reversion of the waveform. It is shown that the higher velocity zone in the lower velocity background is an important characteristic of gas hydrate bed, and that the higher velocity zone usually parallel the seafloor, and that the velocity changes gradually in the higher velocity zone with the highest velocity at the center whereas the lowest at the margin, suggesting that the saturation of gas hydrate zone decreases gradually from the center to the margin. The study reveals that the high resolution velocity analysis is useful not only to search the hydrate spot but also to estimate the rich layer of gas hydrates.

Key words: the northern slope of the South China Sea, gas hydrate, seismic velocity, DIX equation, velocity , inversion

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