Accumulation system for shale gas from Upper Ordovician to Lower Silurian in Sichuan Basin and surrounding areas

Shale sedimentary time,feature,evolution history,present tectonic location,tectonic feature,residual condition,distribution,burial depth and gas content were discussed in this paper.The accumulation system for shale gas from the Upper Ordovician to the Lower Silurian in the Sichuan Basin and the surrounding areas was divided into 7 accumulation systems,including the southern and southeastern Sichuan,the northern Guizhou,the eastern Chongqing,the western Hunan and Hubei,Longmen Mountain,Micang Mountain-Daba Mountain,and the central Sichuan.Shale thickness,organic carbon content,maturity and gas content in each accumulation system were analyzed.The accumulation systems were evaluated at 4 levels as followed: strategic breakthrough,expansion,preparation and perspective area.Exploration targets were also pointed out.