库车坳陷迪那2凝析气田油气成藏过程分析

Hydrocarbon Accumulation Process Analysis of Dina 2 Condensate Gasfield in Kuqa Depression

基于定量颗粒荧光、流体包裹体和激光拉曼等分析手段系统分析了库车坳陷迪那2地区的油气充注史,并结合埋藏史、热史、生烃史及圈闭形成史对其成藏过程进行了探讨。所测试储层样品的QGF指数都大于4,QGF-E强度在5 057 m以内都大于20 pc,结合岩心分析结果确定其现今残余油水界面位于5 057 m左右。结合包裹体岩相学、测温数据及自生伊利石K-Ar测年数据表明,储层经历了三期油气充注,早期（23.53 Ma）充注的重质油由于缺乏有效盖层而散失,且此时地层埋藏较浅,地温低,石英矿物还未进入成岩胶结阶段,因此,无法记录该期油的充注。新近纪喜马拉雅造山运动使地层强烈褶皱,圈闭大量形成,康村晚期（10~7 Ma）烃源岩生成的轻质油聚集其中,该期油充注时间较长,包裹体以蓝绿和蓝色为主。第三期（2.5 Ma）天然气充注强度较大,改造了早期油藏,形成了迪那2凝析气藏的现今面貌。

The hydrocarbon charging history of Dina 2 area of Kuche Depression is systematically analyzed based on quantitative grain fluorescence,fluid inclusion and laser Raman spectroscopy,and the hydrocarbon accumulation process of Dina 2 condensate gas reservoir is discussed by combining the hydrocarbon charging history with the burial history,thermal history,hydrocarbon generation history and trap formation history. The QGF index of the tested reservoir samples is all greater than 4,and the QGF-E intensity is more than 20 PC when depth is less than 5 057 m. Combined with the results of core analysis,it is determined that the present residual oil / water interface locates at about 5 057 m. According to inclusion petrography,temperature data and authigenic illite K-Ar dating data,it is held that the reservoir experienced three stages of hydrocarbon charging： In the first stage,heavy oil was charged at the end of Oligocene（ about 23. 53 Ma）,but it escaped because of the lack of cap rock. And in this period,quartz minerals did not enter into the rock cementation stage due to shallow reservoir depth and low formation temperature,and therefore the oil charging can not be recorded in this stage.In the second stage（ 8 ~ 5 Ma）,the Neogene Himalaya orogeny caused the strong fold of strata and formed a large numbers of traps,in which the light hydrocarbon from the Qiakemake Formation source rock of middle to lower Jurassic and the Huangshanjie Formation source rock of Triassic accumulated. In this stage,the hydrocarbon charging time is long,and the inclusions are mainly blue-green and blue color. In the third stage,a lot of natural gas charged into the reservoir from late Pliocene（ 2. 5 Ma）,which changed the components of the hydrocarbons formed in the early time,and the present Dina 2 condensate gas field was formed.