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为了解岩性在天然气水合物分布中的作用, 利用岩矿鉴定、扫描电镜和能谱法对ODP204航次的 4个站位 10个钻孔共计 115个沉积物样品进行分析, 发现沉积物中矿物成分基本相近, 以粘土矿物为主, 含少量以石英为主的陆源碎屑。样品中含有丰富的硅藻和有孔虫等微体化石, 可形成硅藻粘土—硅藻土、有孔虫硅藻土或凝灰质硅质生物粘土。石英碎屑大多呈棱角状, 粒径小、含量少, 同时, 样品中可见透镜体、团块或旋涡状层状结构以及杂乱堆积的斑杂构造。上述特征表明沉积物为含有大量深海或半深海的浊流沉积物或其夹层。由于钻井岩心中有相当部分的天然气水合物样品分布在上述沉积物中, 推断这些浊流沉积物很可能是ODP204航次天然气水合物的有利储层。
In order to understand the role of lithology in the distribution of gas hydrates, 115 sediment samples from 10 boreholes at four stations of ODP 204 were analyzed by using rock and mineral identification, scanning electron microscopy and energy spectrum. It was found that minerals The components are basically the same, mainly clay minerals, including a small amount of quartz-based terrestrial debris. Samples are rich in diatoms and foraminifera and other microfossils, the formation of diatom clay - diatomaceous earth, foraminiferal diatomite or tuffaceous silica bio-clay. Quartz detritus mostly angular, small particle size, content is small, at the same time, the sample can be seen lenticular body, clumps or swirling layered structure and disorderly accumulation of plaque structure. The above characteristics indicate that the sediment is a turbid flow sediment or interlayer containing a large amount of deep or semi-deep sea. Since a considerable portion of the gas hydrate samples in the drilling core are distributed in the above sediments, it is concluded that these turbidite sediments are likely to be favorable reservoirs for the ODP 204 voyage gas hydrate.