Abstract Xihu anticline is an oil-bearing structure in Sikeshu sag located in the southern margin of Junggar Basin. Great exploration prospect can be seen for the oil and gas show up to 100 m in Qigu Formation of Jurassic. Well Xihu 1 is the first drilling layer for its deep buried depth of Jurassic layers in Xihu anticline. The whole-hydrocarbon geochemical method is used to analyze the composition and carbon isotope of natural gas, as well as the physical properties and geochemical characters of crude oil to clarify the oil origin of this area based on the analyses of source rock characters. From the results, it can be seen that main source rocks are from Jurassic and Paleogene. Crude oil in the research area has relatively heavy carbon isotopes and relatively high Pr/Ph. Regular sterane is distributed in the shape of reverse L and the ratio of gammacerane/C31 hopane value is 0.1, suggesting its origin from source rocks at mature stage.

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准噶尔盆地西湖背斜侏罗纪石油成因及来源

摘要 西湖背斜是准噶尔盆地南缘四棵树凹陷的含油构造。侏罗系七股组油气显示达100 m，勘探前景广阔。西湖1井是西湖背斜侏罗系地层埋深较深的第一钻层。在烃源岩特征分析的基础上，采用全烃地球化学方法分析天然气的成分和碳同位素，以及原油的物性和地球化学特征，明确该区的石油来源。从结果可以看出，主要烃源岩来自侏罗系和古近系。研究区原油碳同位素较重，Pr/Ph较高。