POTENTIAL DISTRIBUTION OF NATURAL GAS HYDRATE IN THE PERMAFROST REGIONS OF QINGHAI-TIBET PLATEAU

Natural Gas hydrate was found in permafrost regions and marine sediments.Permafrost distributes widely in the Qinghai-Tibet plateau which is the potential region for the distribution of natural gas hydrate in China.The temperature model of permafrost distribution is made by the three-dimensional zonation under the GIS.Meanwhile,a regression analysis of the permafrost thickness is carried out using the data of ground temperature drills and gives the spatial distribution characteristics of the annual ground temperature and the thickness of permafrost in the Qinghai-Tibet plateau.Combined with the thermodynamics conditions of forming natural gas hydrate,the potential regions for natural gas hydrate in the Qinghai-Tibet plateau have been studied.The result shows that the natural gas hydrate distributes mainly in northwestern Qiangtang basin,and the reserve is likely to be large.This region is the low temperature center of the Qinghai-Tibet plateau.And,the distribution ranges and reserves of natural gas hydrate decrease with the increase of the geothermal gradients.The thickness of permafrost and geothermal gradients below it are the most important controlling factors of the formation of natural gas hydrate.