青藏高原天然气水合物潜在分布区预测  

Potential distribution of gas hydrate in the Qinghai-Tibetan Plateau

作　　者：祝有海[1] 卢振权[1] 谢锡林[1] 

机构地区：[1]中国地质科学院矿产资源研究所,北京100037

出　　处：《地质通报》2011年第12期1918-1926,共9页Geological Bulletin of China

基　　金：国家重点基础研究发展计划项目(编号:2009CB219501);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)

摘　　要：青藏高原冻土面积约150×104km2,是中国最大的冻土区,具备较好的天然气水合物找矿前景。运用热力学预测方法,根据青藏高原的年平均地表地温、冻土层厚度、冻土层内地温梯度(2.22℃/100m)、冻土层下地温梯度(4.18℃/100m)等参数,分纯甲烷组分、纯二氧化碳组分和各种实测气体组分,分别计算出天然气水合物的稳定带及其厚度,并编制出相应的分布预测图。结果显示,青藏高原大部分冻土区基本具备天然气水合物的形成条件,即使最难形成的纯甲烷水合物也能在部分冻土区内形成。若单纯从温压条件考虑,成矿条件最有利的地区是喀喇昆仑地区,其次为西昆仑地区,再次为羌塘盆地,最后才是祁连山等地区。综合考虑气源条件、运移条件、储层条件等,羌塘盆地是青藏高原天然气水合物形成条件和找矿前景最好的地区,其次是祁连山地区、风火山—乌丽地区,再次是昆仑山垭口盆地、唐古拉山—土门地区、喀喇昆仑地区、西昆仑—可可西里盆地等。The Qinghai-Tibetan Plateau is the largest permafrost in China with an area of 150 xi04km2, which is a potential and prospective region for gas hydrate. Based on the mean annual ground temperature, the thickness of frozen layer, thermal gradient in frozen layer （2.22°C/100m） and thermal gradient below frozen layer （4.18°C/100m）, the stability zones and their thickness of gas hy- drate with pure methane, pure carbon dioxide and various measured gas compositions from the Qinghai-Tibetan Plateau permafrost are calculated by using the thermodynamic method, and the potential distribution regions of gas hydrate are predicted and mapped. The results show that the Qinghai-Tibetan Plateau permafrost is of basic thermodynamic condition for formation of gas hydrate even including pure methane hydrate. According to temperature and pressure conditions, the best prospective region for gas hydrate is Kalakunlun Mountains, and next is Xikunlun Mountains, then Qiangtan Basin, and Qilianshan Mountains etc. However, combined with gas sources, transportation and reservoir conditions, Qiangtan Basin is the best prospective region for gas hydrate, next is Qilian- shan Mountains and Fenghuoshan-Wuli, and then includes Kunlun Mountains Yakou Basin, Tanggula Mountains-Tureen, Kalakun- lun Mountains. Xikuulun Mountains-Kekexili Basin etc.

关 键 词：天然气水合物 稳定带 冻土 青藏高原 

分 类 号：P618.13[天文地球—矿床学]