Gas Hydrates in the Qilian Mountain Permafrost and Their Basic Characteristics
祁连山冻土区天然气水合物及其基本特征

The Scientific Drilling Project of Gas Hydrate in Qilian Mountain permafrost, which is located in Jugenghu mining area of the Muli Coalfield, Tianjun County, Qinghai Province, was implemented by Institute of Mineral Resources, Institute of Exploration Techniques, Qinghai No.105 Coal Geological Exploration Party and some other units during 2008-2009. Samples of gas hydrate were collected firstly from the hole of DK-I on November 5, 2008 and again from the hole of DK-2 and DK-3 in 2009. This is the first discovery of gas hydrate in China's permafrost and in the low-middle latitude permafrost of the world. Gas hydrates were found at the 133-396m intervals of Middle Jurassic Jiangcang Formation lying under the permafrost zone (about 95m). Gas hydrates occur in the fissures of siltstones, mudstones and oil shale, or in the pores of sandstones. Samples are white or ivory crystals and liable to burn. Obvious low temperature anomaly was identified by the infrared camera.The gas hydrate-bearing cores strongly bubble in water. Gas-bubble and water-drop are emitted from the samples and the characteristic honeycombed structure is retained. The typical spectrum curve of gas hydrate was detected by means of Raman spectrometry. Furthermore, the logging profile also indicates high electrical resistivity and sonic velocity. Gas hydrate in Qilian Mountain permafrost is a new type hydrate characterized by a relatively thin permafrost zone, shallow buried depth, complex gas components, and coal-bed methane origin.