柴西北尖顶山地区油源及油气成藏研究

HYDROCARBON SOURCE AND THE ACCUMULATION IN JIANDING MOUNTAIN,NORTHWEST QAIDAM BASIN

尖顶山和南翼山是柴达木盆地西部北区的两个相邻构造,尖顶山浅层获得工业油气流,但深层一直没有大的突破,而南翼山构造深浅层都发现较大油气储量,因此解剖该地区的油源及成藏特征对勘探具有重要的指导意义。应用原油轻重组分的地球化学特征综合判识油源,指出尖顶山油田N22储层原油主要来自N1成熟源岩。在成藏过程中,有沿途或浅层低-未成熟油的混入,深层储层抽提物来自E23源岩。分析认为储层原油属于成熟阶段的产物且是就近捕获,不是从南部源岩长距离运移而来。结合源岩生烃史与构造演化史,建立了成藏模式。

Jianding Mountain and Nanyi Mountain are the two adjacent structures in the northwest of Qaidam basin.Commercial oil and gas flow has been recovered in the shallow formation but nothing obtained in the deep formation of Jianding Mountain,so the accumulation model study of Jianding Mountain oil and gas structure is significant to the future exploration.In this paper,the authors apply the special geochemical characteristics of the different components of crude oil to identify the oil and gas source and explain successfully the reason why the oil maturity is higher than that of rock maturity,point out that the oil of N22 of Jianding Mountain comes from N1 matured hydrocarbon source rocks and mixed with low-matured oil in the accumulation process,and the reservoir extracts of the deep formation is provided by the E23 matured hydrocarbon source rocks.It is recognized that the oil of Jianding Mountain is matured,and it comes from the hydrocarbon source rocks in the vicinity,not from the south of Qaidam Basin.Finally,the authors build the reservoir accumulation model of the Jianding Mountain reservoirs integration with hydrocarbon generation history and tectonic movement history.