川西叠覆型致密砂岩气区地质特征

摘要

根据川西致密砂岩气藏成藏地质背景、成藏特点和气藏特征，提出了叠覆型致密砂岩气区概念。川西叠覆型致密气区具有叠合性、广覆性、节律性、模糊性和多样性五性特征。叠合性：原型盆地的叠合性、构造形变的叠合性、储层的叠合性、成藏组合的叠合性、气藏的叠合性；广覆性：源岩分布的广覆性、储层分布的广覆性、圈闭分布的广覆性、气藏分布的广覆性；节律性：构造演化的节律性、沉积演化的节律性、运移充注的节律性；模糊性：气水边界的模糊性、圈闭类型的模糊性、储层的非均质性；多样性：烃源的多样性、储集类型的多样性、运移方式的多样性、气藏类型的多样性。川西叠覆型致密砂岩气区总体具有“源、相、位”三元控藏特点。%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 assem-blage. 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, migra-tion and infilling. Ambiguity refers to the fuzzy properties of gas-water boundary, trap types and the heterogenei-ty 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.