Research Summarization on Natural Gas Hydrate in Permafrost Regions

Because of the latent energy prospect and its impacts on the climate and the environment,many countries began the studies on natural gas hydrate in permafrost regions and achieved great research progresses subsequently.The relations between natural gas hydrate and permafrost,the reserves of natural gas hydrate in permafrost regions and the present research situations of natural gas hydrate in representative permafrost regions are explained in this paper.The results indicated that the formation conditions of natural gas hydrate such as temperature and pressure were restricted by permafrost and the natrual gas hydrate with self-preservation was discovered inside the permafrost layer.The accumulation and transfer of free gas in sediment were influenced by permafrost.Besides,the thawing of permafrost could raise the pore pressure.The present estimations of the natural gas hydrate reserves in permafrost regions were not integral or all-around,which were only made in some representative permafrost regions.The estimation showed that the natural gas hydrate reserves in Northslope in Alaska,US were about 1.0×1012~1.2×1012 m3,about 1.6×1013 m3 in Beaufort,Makenzie Delta,and about 1.7×1013 m3 above 250 m depth in west Siberia.The existence of natural gas hydrate in Qinghai-Tibetan Plateau is an important issue which demands prompt understanding.