青海木里三露天冻土区天然气水合物钻孔岩心顶空气组成及指示意义

摘要

Through the analysis on hydrocarbon gas components at different depths in headspace gases from the cores in DK8-19,DK10-16,DK10-17,DK11-14,DK12-13,DK13-11 in Sanlutian area of Muli,the distribu-tion relationship of the sections with anomalistic gas component content,gas hydrate output layers,oil and gas output layers,faults or fracture zones output layers was discussed.The results show that the anomalistic gas component content sections can be compared with those of gas hydrate and its major anomaly output layers,and oil and gas output layers;the abnormal section can be used as an indication of gas hydrate and its major anoma-lies and oil and gas.The relationship between variation of hydrocarbon gas content in headspace gases and the location of faults or fracture zones shows that different levels of fault system from the deep can provide a channel for deep hydrocarbon gas migration or existing space for the formation of gas hydrate.The results show that the gas component of headspace gas has important significance for gas hydrate and its major anomalies,the oil and gas and the migration of hydrocarbon.%对青海木里三露天地区 DK8-19、DK10-16、DK10-17、DK11-14、DK12-13、DK13-11共6个天然气水合物钻孔岩心顶空气气体组分进行分析测试，并将获得的各孔岩心顶空气组分含量变化与天然气水合物及其异常层段、油气显示层段、断层或破碎带分布之间的空间关系进行对比分析。结果显示：6个钻孔岩心顶空气中烃类气体高含量区间均与天然气水合物及其异常层段、油气显示层段具较好的对应关系，其高值区间可作为天然气水合物、油气显示的一种指示；距断层或破碎带产出位置不同的岩心顶空气组分含量变化特征显示，不同级次的断裂系统为烃类气体向上运移提供通道，部分可为天然气水合物提供赋存空间。研究结果说明顶空气组成对天然气水合物及其异常现象、油气显示现象、烃类气体运移作用有重要指示意义。