Organic inclusion and hydrocarbon charging events of the Bagung Formation in the Quemoco area, Qiangtang Basin

The Upper Triassic Bagung Formation is one of the most important hydrocarbon-bearing strata in the Qiangtang Basin.Based on the analysis of fluid inclusion facies, microscopic temperature measurement and microscopic fluorescence analysis, the brine inclusions in the sandstone of the Bagung Formation in Quemoco area recorded 4 stages of thermal fluid activity, of which the second to the third stage fluid contain two types of oil phase inclusions.In stage 2 to stage 3 of thermal fluid activity, a small number of yellowish fluorescent oil inclusions are mainly distributed in the cracks within the quartz particles, and a large number of blue fluorescent oil inclusions are mainly distributed in the quartz secondary enlarged side.Based on the occurrence and fluorescence spectrum characteristics of the two types of oil inclusions, combined with comprehensive analysis of stratigraphic burial history and hydrocarbon generation history, it is considered that they represent a period of Late Jurassic oil and gas filling, which is consistent with the central basin.