关键词: 成藏模式, 富集高产规律, 致密砂岩气输导体, 三叠系须家河组, 川西坳陷, 四川盆地

Abstract: There is enormous resources potential in the Xujiahe Formation of Sichuan Basin. Owing to the tight reservoir, the fault-fracture bodies have high and unstable hydrocarbon production, as well as limited reserves scale; the tight sandstone reservoirs have low production, and cannot achieve benefits and efficiency, although with large reserves. In order to solve the key problems that limit efficient exploration, i.e., high production, stable production and reserves scale, the new prospecting idea for tight sandstone gas carrier beds has been formed by integrating the exploration ideas for conventional natural gas in reservoirs and shale gas from source rocks. Specifically, the paper establishes the accumulation model of "dual source hydrocarbon supply, transportation by fault-fracture bodies, composite hydrocarbon accumulation" for tight sandstone gas, and also clarifies the hydrocarbon enrichment and high production laws of "spatiotemporal superposition of structure-transportation for controlling reservoir enrichment, effective fracture controlling production in later period, composite combination of source rocks, low-permeability matrix reservoirs and carrier beds for controlling stable production". Guided by the accumulation models for tight sandstone gas carrier beds, as well as the hydrocarbon enrichment and high production laws of tight sandstone gas, 15 wells deployed in the Hexingchang area of western Sichuan depression achieved high yield, thus solving the problem of "rich resources without reserves, large reserves with low production, high production without gas fields" in Xujiahe Formation, Sichuan Basin. Additionally, the field with the proven reserves of 100 billion cubic meters was built in Hexingchang area, western Sichuan depression. On this basis, the efficient exploration and development of ultra-low permeability tight sandstone gas reservoirs in the Xujiahe Formation of western Sichuan depression has been achieved. These achievements have important guidance significance for the efficient exploration and development of tight sandstone gas reservoirs in Sichuan Basin and similar sedimentary basins.

Key words: accumulation models, enrichment and high production regularities, tight sandstone gas carrier bed, Triassic Xujiahe Formation, western Sichuan depression, Sichuan Basin