The Comparative Analysis On Geological Conditions Of Shale Gas In Typical Areas In China

The geological conditions of potential shale in China are complicated and the regional geological background of shale gas have some differences and similarities.The Lower Paleozoic potential shale in the Southwest mainly developed in the Marined facies,Mesozoic in the continental facies.The Upper Paleozoic shale in the North mainly developed in marine-terrigenous facies,Mesozoic and Cenozoic in terrigenous facies.The potential shale in Northwest developed in marine,continental and transitional facies.The potential shale in Southwest and Northwest formed earlier than the North.The shale mainly formed in the Cambrian,Ordovician-Silurian,Permian,Triassic and Jurassic.The Northwest formed in the Cambrian,Ordovician,Carboniferous,Triassic,Jurassic,Cretaceous and the North mainly formed in Carboniferous-Permian Triassic and Paleogene.The potential shale in the Southwest mainly developed in foreland basins and residual tectonic areas,the North mainly distributed in foreland basins and fault depressions,and the Northwest mainly distributed in foreland basins.The lithologic structure of potential shale in the Southwest changed gradient,with large thickness,wide distribution and good continuity.The North and Northwest mainly composed of sand and peat interbed,with thin thinkness.The potential shale in Southwest is residual and dispersed,with high abundance and maturity of organic matter,suffered violent tectonic movements and poor preservation conditions.The maturity of organic matter and preservation conditions are the key factors for the occurrence of shale gas.The potential shale in the North sufferd weak tectonic movements,with high abundance and low maturity of organic matter and good preservation conditions.The maturity of organic matter is the key factor for the occurrence of shale gas.The shale in Northwest sufferd weak tectonic movements,with thin thickness,low abundance and maturity of organic matter and good preservation conditions.The abundance and maturity of organic matter are the key factors for the occurrence of shale gas.