南海东北部陆坡海底甲烷渗漏及水合物成藏特征

发布时间：2018-11-07 13:45

【摘要】：根据近年天然气水合物地质、地球化学和地球物理调查资料,结合2013年钻孔成果,分析南海东北部陆坡海底甲烷渗漏特征及其对水合物成藏的影响,探讨了水合物成因模式。研究表明,南海东北部陆坡海底存在高通量甲烷渗漏体系,甲烷渗漏引起的地质、地球化学指标异常非常明显。大量块状、脉状、结核状渗漏型水合物也被发现,其成因应与高通量甲烷渗漏有关。其典型成因模式是高通量甲烷以游离态渗漏方式沿断层或裂缝体系向浅部地层运移,以气烟囱形式在稳定带的不同部位形成渗漏区,甲烷在气烟囱顶端或侧翼聚集而形成水合物矿藏。影响水合物成藏的断层主要为长期活动的继承性正断层、层间断层以及与海底滑塌密切相关的活动断层,气烟囱对渗漏型水合物成藏有明显的控制作用。
[Abstract]:Based on the geological, geochemical and geophysical survey data of natural gas hydrate in recent years, combined with the results of drilling in 2013, the characteristics of methane leakage on the northeast slope of the South China Sea and its influence on the formation of gas hydrate are analyzed, and the genetic model of hydrate is discussed. The study shows that there is a high-throughput methane leakage system on the seabed of the northeastern South China Sea, and the geological and geochemical anomalies caused by the methane leakage are very obvious. A large number of massive, veined and nodule percolating hydrates have also been found, which may be related to the leakage of high throughput methane. The typical genetic model is that the high flux methane moves along the fault or fracture system to the shallow strata in the form of free leakage, and forms the leakage area in different parts of the stable zone in the form of gas chimney. Methane accumulates at the top or flank of a gas chimney to form hydrate deposits. The faults affecting hydrate formation are mainly inherited normal faults, interlayer faults and active faults closely related to submarine collapse. Gas chimneys have obvious control effect on the formation of percolating hydrates.
【作者单位】：中国地质大学(武汉);广州海洋地质调查局国土资源部海底矿产资源重点实验室;
【基金】：国家天然气水合物专项(编号:GZH201100301;GZH201100305;GZH200200203)联合资助
【分类号】：P618.13

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