哈拉湖坳陷与木里坳陷天然气水合物成藏条件对比  

A comparative study of accumulation conditions of gas hydrates in the Hala Lake Sag and Muli Sag

作　　者：张鹏辉[1,2,3] 何梅兴 白大为[1,2,3] 杜炳锐[1,2,3] 裴发根 张小博[1,2,3] 吕琴音 

机构地区：[1]国土资源部地球物理电磁法探测技术重点实验室,河北廊坊065000 [2]国家现代地质勘查技术研究中心,河北廊坊065000 [3]中国地质科学院地球物理地球化学勘查研究所,河北廊坊065000

出　　处：《物探与化探》2017年第6期1160-1166,共7页Geophysical and Geochemical Exploration

基　　金：国家高技术研究发展计划"863计划"课题(2012AA061403);国家127专项项目(GZHL20110324;GZH201400305);中国地质调查局地质调查项目(DD20160224);中央公益性科研院所基本科研业务费专项基金项目(AS2014J08)

摘　　要：在已发现水合物的木里坳陷冻土条件、烃源岩条件和温压环境等水合物成藏条件研究的基础上,通过类比法探讨哈拉湖坳陷天然气水合物的发育和赋存潜力。结果表明:两个坳陷具有相近的冻土层厚度、基本一致的温压条件等,指示哈拉湖坳陷基本具备天然气水合物形成的环境条件。在沉积演化、冻土层物质组成、烃类气体保存等方面两者具有较大的差异,木里坳陷的地层发育较完整,冻土层以沉积岩石为主,地球化学具有明显异常;哈拉湖坳陷石炭纪和侏罗纪发生沉积间断,三叠统含油气系统遭受破坏,冻土层物质以第四纪沉积为主,封盖能力差。埋藏较深的二叠统烃源岩可能能够为天然气水合物的形成提供烃类气体,推测哈拉湖坳陷局部隆起部位可能是天然气水合物赋存的有利区域。On the basis of researches on the hydrate accumulation conditions of permafrost, source rock and temperature-pressure of the hydrate-discovered Mull Sag, geological analogue methods were applied to analyzing the development and occurrence potential of natural gas hydrate in the Hala Lake Sag. The results show that the Hala Lake Sag and Muli Sag have the same permafrost thickness and consistent temperature-pressure conditions, which indicates that the Hala Lake Sag basically possesses the environmental conditions for the gas hydrate formation. With regard to sedimentary evolution, material composition of the permafrost and hydrocarbon gas preserva- tion, they display notable differences. Formations in the Muli Sag are well developed, the permafrost layer is primarily sedimentary rock, and distinct geochemical anomalies were detected. However, a depositional hiatus occurred between the Carboniferous and Juras- sic in the Hala Lake Sag, the Triassic petroleum system was destroyed, and the Quaternary sediments are the main materials of perma- frost, with poor capping capacity. Deeply buried Permian source rocks could provide hydrocarbon gases for gas hydrate formation. It is inferred that the local uplift of the Hala Lake Sag is a favorable region for the formation of gas hydrate.

关 键 词：哈拉湖坳陷 成藏条件 冻土层 天然气水合物 成藏潜力 

分 类 号：P631[天文地球—地质矿产勘探]