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Coal measure source rocks,located in the Xihu Sag of the East China Sea Shelf Basin,were analyzed to define the hydrocarbon generation potential,organic geochemistry/petrology characteristics,and coal preservation conditions,The Pinghu source rocks in the Xihu Sag are mainly gas-prone accompany with condensate oil generation.The coals and shales of the Pinghu Formation are classified from fair to excellent source rocks with total organic carbon (TOC) contents ranging from 25.2% to 77.2% and 1.29% to 20.9%,respectively.The coals are richer in TOC and S1+S2than the shales,indicating that the coals have more generation potential per unit mass.Moreover,the kerogen type of the organic matter consists of types Ⅱ-Ⅲ and Ⅲ,which the maturity Ro ranges from 0.59% to 0.83%.Petrographically,the coals and shales are dominated by vitrinite macerals (69.1%-96.8%) with minor proportions of liptinite (2.5%-17.55%) and inertinite (0.2% -6.2%).The correlation between maceral composition and S1+S2 indicates that the main contributor to the generation potential is vitrinite.Therefore,the coals and shales of the Pinghu Formation has good hydrocarbon generation potential,which provided a good foundation for coal measure gas accumulation.Furthermore,coal facies models indicates that the Pinghu coal was deposited in limno-telmatic environment under high water levels,with low tree density (mainly herbaceous) and with low-moderate nutrient supply.Fluctuating water levels and intermittent flooding during the deposition of peat resulted in the inter-layering of coal,shale and sandstone,which potentially providing favorable preservation conditions for coal measure gas.