Geological characteristics of superposed tight sandstone gas-bearing areas in western Sichuan

Based on the geologic background, reservoir forming features and reservoir characteristics of tight sandstone gas reservoirs in the western Sichuan, the concept of superposed tight sandstone gas-bearing areas has been proposed. The superposed tight sandstone gas-bearing areas in the western Sichuan have the characteristics of superimposition, extensive spread ability, rhythmicity, ambiguity and diversity. Superimposition refers to the superimposed properties of prototype basin, tectonic deformation, reservoir stratum and reservoir forming assemblage. Extensive spread ability refers to the wide distribution features of source rock, reservoir stratum, trap and gas reservoir. Rhythmicity refers to the rhythm properties of structural evolution, sedimentary evolution, migration and infilling. Ambiguity refers to the fuzzy properties of gas-water boundary, trap types and the heterogeneity of reservoir. Diversity refers to the variety of source rocks, reservoir types, migration patterns and gas reservoir types. Generally speaking, the superposed tight sandstone gas-bearing areas in the western Sichuan have the three-elements (source, facies, position) reservoir-controlling characteristics.