Geological structure and mineralization mechanism of shale gas in the Red Rock Creek Tunnel

Red Rock Creek Tunnel is a long and large tunnel of Yonglong highway. After sorting through the geological structure and the mineralization mechanism of shale gas, we obtain the understanding in four aspects. In general, the geological structure of red rock creek tunnel is relatively simple, the change of tectonization will lead to joint fissure development and the fracture of rock mass. Karst tend to grow on the contact zone of soluble and non-soluble rock or unconformity surface. Shale matrix pore and fracture constitute the main reservoir space of shale gas, the crack provides a migration path for the shale gas as well; the pore size can significantly affect its occurrence form. In the process of mineralization, shale gas authigenic constitutes the mechanism sequence from the absorption aggregation and the enrichment of expansion gap to piston-like movement or replacement migration.