The Research on Reservoir Characteristics of Lower Cambrian Shale Gas in Northeast Chongqing

The Dabashan arcuate tectonic belt in Northeast Chongqing is located at the northern margin of the Yangtze Craton,which is a thrust belt formed by the multi-stage superposition. In the area, the Lower Cambrian is a set of open marine shelf sediments, where developed the organic carbon black and siliceous shale. The set of shale gas has various types of reservoir space, their pore diameters are 3.1~5.6 nm, their BET specific surface area is 8.26 m²/g, which is typical low porosity and low permeability. The dark shale is mainly composed of quartz and feldspar, and the clay minerals take second place, and the carbonate minerals are generally low. This set of reservoir has a good capacity of shale gas adsorption and gas-bearing shows, which an important layer for the exploration and evaluation of shale gas in this region.