摘要
The Permian-Triassic natural gas migration paths and accumulation patterns in the central-western Sichuan region are studied based on the three-dimensional shape,exciting light intensity and fingerprint characteristics of aromatic hydrocarbons fluorescence spectra of gas field water.The Permian-Triassic gas field water in the central-western Sichuan Basin has(condensate) gas reservoir impact characteristics,and has three subclasses(base peak,double peak and odd peak,mainly the stable type of base peak subclass) and seven types of three-dimensional fluorescence characteristics.Three-dimensional fluorescence characteristics of the water of the Permian to Middle and Lower Triassic differ from that of the Upper Triassic Xujiahe Formation.The former is mainly influenced by hydrocarbons from high to over mature Lower Paleozoic marine shale and Upper Permian Longtan Formation coal,while the latter is mainly by its own source rock maturity differences and organic matter type difference.Research on the three-dimensional fluorescence characteristics indicates that the Upper Permian Middle and Lower Triassic reservoirs in the Moxi structure mainly accumulate gas from vertical migration;gas in the reservoirs below the Leikoupo Formation originates mainly from the Longtan Formation coal,while the Leikoupo Formation gas reservoir includes gas from gypsum-salt rock section;gas in the Xujiahe gas reservoir in the Pingluoba structure is mainly migrated from central-southern faults and the reservoirs have strong heterogeneity on plan.