Study Of Hydrocarbon Accumulition Process Of Lower Assemblage In Middle Yangtze

Petroleum reservoir of lower assemblage in middle Yangtze are analyzed by correlation of petroleum source,study on hydrocarbon accumulation period and basin modeling.The results show that the Lower Cambrian mudstone and the Lower Silurian mudstone are the main hydrocarbon supplying stratas of Lower Assemblage in Middle Yangtze The time that Paleozoic source rock generated oil is mainly during Devonian to Permian period and till Jurassic.Jurassic is also the major period that Silurian source rock supplied hydrocarbon.This benefits late hydrocarbon accumulation.There has been three-stage uplift-cooling in western Hubei and eastern Hunan since Yanshan period.Denudation extent enhance constantly from northwest to southeast.The degree of tectonics in Yanshan-Xishan period controlles the effectiveness of preservation condition.Western Hubei and estern Hunan is on the higher position of palaeohigh.This is good for oil and gas migration and accumulation.The time of hydrocarbon generation and evolution in western Hubei and eastern Hunan is later.Silurian hydrocarbon source rock keep good hydrocarbon-generation condition.Western Hubei and eastern Hunan area uplifts late with lower degree.Sealing condition is influced slightly.Therefore,western Hubei and eastern Hunan area is the favorable exploration zone of shale gas.