摘要
对青海祁连山冻土区天然气水合物钻井(DK一3)岩心进行了沉积学分析。根据对钻井地层特征、粒度、矿物含量的综合分析,在DK一3钻井揭露的中侏罗统中识别出4种沉积相类型,并完成了沉积微相的划分。伴随地层由老到新,沉积环境由最初发育的辫状河过渡到相对稳定的湖泊(辫状河一曲流河—+曲流河三角洲一湖泊)。在133-156m和225.1-240m井段的岩层中发现的天然气水合物,主要呈薄层状分布于岩石裂隙面上;而在367.7-396m井段,天然气水合物除存在于岩石裂隙中外,在砂岩孔隙中亦大量存在。天然气水合物的产出与沉积环境、构造条件有着密切的联系。
A sedimentological study of natural gas hydrate borehole DK-3 was carried out. All the core samples were collected from Qilian Mountain permafrost. Through a comprehensive analysis of stratigraphy, grain size and XRD of the samples, four types of Mid- dle Jurassic sedimentary facies were recognized. With the variation of the strata from old to young, the sedimentary facies evolved gradually from braided river, meandering river, meandering river delta to lake facies, together with the changes of microfacies. The natural gas hydrate existent in 133-156 m and 225.1-240 m is mainly distributed in flaggy-shaped rock fractures. In 367.7-396 m, the natural gas hydrate not only exists in the rock fractures but also is abundant in sandstone pores. It is concluded that the distribution and storage of natural gas hydrate is closely related to the sedimentary environment and structural conditions.
出处
《地质通报》
CAS
CSCD
北大核心
2011年第12期1829-1838,共10页
Geological Bulletin of China
基金
中国地质调查局项目<青藏高原冻土带天然气水合物调查评价>(编号:1212010818055)
关键词
天然气水合物
冻土区
沉积环境
粒度
XRD
祁连山
natural gas hydrate permafrost sedimentary environment grain size XRD Qilian Mountain