Accumulation of Upper Cambrian ancient reservoir in Wangcun, southern margin of middle Yangtze region

Based on microscopic observation and micro-thermometry measurement of fluid inclusions,combined with basin simulation and crude oil pyrolysis calculation,it is discussed in this paper the Upper Cambrian reservoir in Wangcun,the southern margin of the middle Yangtze region.During the Caledonian period,the southern margin of the middle Yangtze region accepted hydrocarbon from the Lower Cambrian source rocks.In some regions,the Upper Sinian source rocks also worked as effective hydrocarbon kitchens.Wangcun,located on the slope,was the destination of hydrocarbon migration,resulting in primary pool.During the Early and Middle Triassic,primary pools in Sinian and the Middle and Lower Cambrian adjusted due to the Indosinian Movement and the Wangcun ancient reservoir was formed.From the Late Triassic to the Early Jurassic,the Wangcun ancient reservoir was buried deep as the result of flexing or thrust-nappe effect.Crude oils cracked rapidly and oil-cracking-gas source kitchen supplied hydrocarbon in succession.The Wangcun reservoir transformed to gas pool completely,accelerating the dissipation rate of oil and gas.Due to the strong deformations during Yangshan and Himalayan stages,the ancient reservoir finally disappeared.