库车坳陷秋里塔格构造带中东段油气充注期次及成藏模式OACSTPCD

There is great exploration potential in Qiulitag Structural Belt,Kuqa Depression.In the Pa-leogene gypsum-salt phase transition zone,the reservoir sandstone thickness is thin and the process of hydrocarbon accumulation is complicated.In order to reveal the hydrocarbon charging stage and accu-mulation model,the fluid records about hydrocarbon in the intersalt thin sandstone of Kumugeliemu Group was studied by microscopic observation,Laser Raman spectroscopy,temperature measurement of inclusion,basin simulation,quantitative fluorescence spectroscopy of reservoir.The results show that:from the end of Paleogene to the Early Miocene,medium oil gathered on the top of Cretaceous sandstone;in the Middle Miocene,the charging of light oil-condensate occurred at 14.2 Ma,forming blue-green fluorescent inclusion assemblages and widely distributed paleo-oil reservoirs;between the Late Miocene and the Middle Pliocene,the ancient oil reservoirs were leaked by the development of thrust faults and structural fractures with the more intense tectonic compression;since the Late Plio-cene,methane started charging at 3.7 Ma because of the recovering of gypsum-salt's sealing property with the deeper burial in Kumugeliemu Group,which is purer and thicker.The inclusions with methane and intersalt sandstone gas reservoir also formed at this period.The oil-gas accumulation model con-trolled by the dual control of gypsum-salt caprock and tectonic action.The result provides a reference case for further exploration in the middle-east section of Qiulitag Structural Belt.