Accumulation conditions of shale gas reservoirs in the Lower Cambrian Qiongzhusi formation,the Upper Yangtze region

In China,shale gas will be an important,realistic and new alternative energy resource for the growth of natural gas reserves in future.By using of the geological data,gas show in drilling and geochemical information from the Lower Cambrian black shale in Qiongzhusi formation in the Upper Yangtze region,this paper analyzed the accumulation condition of shale gas reservoirs.It is believed that this area is the most favorable for forming shale gas resource because it develops black shale characterized by stable regional distribution and presents three distribution areas of excellent source rocks such as southern Sichuan,northern Guizhou and western Hunan and Hubei closely related to bay environment system;Along Weiyuan and Bijie-Dafang in northwestern Guizhou,there encounters gas show in different level such as gas cut and well kicks when drilling the Lower Cambrian black shale in Qiongzhusi formation during exploring gas reservoir in Sinian Dengyin formation in which parts of black shale contain low-medium commercial adsorption gas ranging from 0.4-0.83 m3/t tested by pressure coring data,especially the shale in Jiulaodong in Weiyuan area shows such distribution characteristics as it is not controlled by gas-water boundary and tectonic factors but closely related to the distribution of efficient shale.It is suggested that the southern China and the northern Guizhou in China should be areas with high priority for exploring shale gas resources after comprehensive study.