东濮凹陷西部斜坡带混合原油地球化学特征

Geochemical characteristics of the mixed oil in western slope belt of Dongpu Depression

东濮凹陷西部斜坡带原油地球化学特征同凹陷内其他地区原油明显不同,而研究程度相对较低.系统分析了原油饱和烃、芳烃组成及生物标志物,研究结果表明:原油生油母质类型较好,以低等水生生物为主,陆源高等植物占次要地位;原油中伽玛蜡烷含量高,类异戊二烯烃呈植烷优势,表明源岩沉积环境为强还原的半咸化-咸化湖相;原油成熟度参数具有不一致性,表明原油并非是低熟油,应为混合原油,其主要来源于沙三段成熟烃源岩.

The geochemical characteristics of the crude oil in the studied area are different from those of the oil in other areas of the depression.The systemical analyses of the saturated hydrocarbon composition,aromatic composition and biomarkers of the crude oil show that,the type of the oil-generating organisms of the crude oil is good,the majority of which is low-grade hydrobionts and the minority of which is high-grade terrigenous plants.There is high content of gammacerane in the oil,phytane predominates in isoprenoid alkenes,which indicate the paleoenvironment of source rocks is reductive brackish-salt lake facies.The maturity parameters of the crude oil are inconsistent,which indicates the oil is not immature oil but is mixed oil,and the majority of the oil comes from the mature source rock of Shahejie Formation.