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现代地质 ›› 2015, Vol. 29 ›› Issue (1): 155-162.

• 非常规资源勘探 • 上一篇    下一篇

海底峡谷侵蚀—沉积作用与天然气水合物成藏

苏明1, 2,沙志彬3, 4,匡增桂3,乔少华1, 2, 5,梁金强3,杨睿1, 2, 6,吴能友1, 2,丛晓荣1, 2   

  1. (1.中国科学院 天然气水合物重点实验室,广东 广州510640;
    2.中国科学院 广州天然气水合物研究中心,广东 广州510640;3.广州海洋地质调查局,广东 广州510760;
    4.中国地质大学(武汉)资源学院,湖北 武汉430074;5.中国科学院大学,北京100049;
    6.中国科学院 边缘海地质重点实验室,中国科学院 南海海洋研究所,广东 广州510301)
  • 出版日期:2015-01-29 发布日期:2015-04-21
  • 通讯作者: 沙志彬,男,高级工程师,1971年出生,石油地质专业,主要从事海域天然气水合物的研究工作。
  • 作者简介:苏明,男,博士,副研究员,1983年出生,海洋地质专业,主要从事深水沉积体系及资源效应、海域天然气水合物成藏地质条件分析等方面的科研工作。Email: suming@ms.giec.ac.cn。
  • 基金资助:

    国家自然科学基金项目(41202080);中国石油科技创新基金研究项目(2013D-5006-0105);油气藏地质及开发工程国家重点实验室(成都理工大学)开放基金项目(PLC201407);广东省自然科学基金博士启动项目(S2012040006333);中国科学院重点部署项目(KGZD-EW-301)。

Erosion and Sedimentation of the Submarine Canyons and the Relationship with Gas Hydrate Accumulation

SU Ming1, 2, SHA Zhi-bin3, 4, KUANG Zeng-gui3, QIAO Shao-hua1, 2, 5,LIANG Jin-qiang 3, YANG Rui 1, 2, 6, WU Neng-you 1, 2, CONG Xiao-rong 1, 2   

  1. (1.Key Laboratory of Gas Hydrate, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou,
    Guangdong510640, China;2.Guangzhou Center for Gas Hydrate Research, Chinese Academy of Sciences, Guangzhou,
    Guangdong510640, China;3.Guangzhou Marine Geological Survey, Guangzhou, Guangdong510760, China;
    4.Faculty of Earth Resources, China University of Geosciences, Wuhan, Hubei430074, China;
    5.University of Chinese Academy of Sciences, Beijing100049, China;6.Key Laboratory of Marginal Sea Geology,
    South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou,Guangdong510301, China)
  • Online:2015-01-29 Published:2015-04-21

摘要:

近年来海底峡谷和海域天然气水合物的调查和研究表明,二者在空间分布上具有一定的相似性,同时海底峡谷强烈的侵蚀作用和良好的内部建造,与海域天然气水合物的聚集、分布和成藏具有直接或间接的关联。通过对目前海底峡谷和海域天然气水合物的资料调研和系统分析,指出海底峡谷和海域天然气水合物的相关性主要表现在3个方面:侵蚀-沉积作用与有利沉积体的分布、侵蚀-沉积作用与含烃流体渗漏的相互作用、侵蚀-沉积作用与海域天然气水合物的动态成藏。将海底峡谷和水合物的关联性应用到珠江口盆地海底峡谷群,初步分析了二者的关联。研究认为该区域的海底峡谷将会对有利沉积体进行破坏和改造,使其表现为“斑状/补丁状”的平面分布特征,影响了水合物的分布和实际产出;此外,峡谷侵蚀-沉积作用导致了先前形成的水合物的分解,一部分的甲烷等气体将会进入到海水之中,而受有利沉积体上部细粒均质层的遮挡,大部分的含气流体将被“继续”限制在有利沉积体之中而形成新的水合物,这可能是该区域内细粒沉积物中水合物饱和度较高的原因。

关键词: 海底峡谷, 侵蚀-沉积作用, 天然气水合物, 成藏机制

Abstract:

  Recent researches on the submarine canyon and the marine gas hydrate indicated that they had the similar spatial distribution. Moreover, because of the erosion and internal architecture, submarine canyons showed the good relationship with the accumulation and distribution of marine gas hydrates. Based on the integrated analysis of studies in the past decade, the correlations between canyons and hydrates could be summarized as three points, i.e.erosion and sedimentation of canyons controlling the distribution of deposits favorable for hydrate, potential leak mechanism between submarine canyons and hydrocarbon-bearing fluid release, and the dynamic accumulation of gas hydrates influenced by submarine canyons. The correlations were used in the submarine canyons in the Pearl River Mouth Basin. On the one hand, these canyons could erode the favorable deposits and further influence the distribution of gas hydrates, and on the other hand, due to the erosion and sedimentation of canyons, the pre-existing hydrates might be dissociated. Impeded by the fine-grained homogeneous layer, most of the dissociated gases would be restricted in the favorable deposits and form the new hydrates, which could be used to help understanding the relatively high saturation of gas hydrate in the fine-grained sediments in the Shenhu Area, northern South China Sea.

Key words: submarine canyon, erosion and sedimentation, gas hydrate, accumulation mechanism

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