海拉尔盆地乌尔逊南斜坡带原油特征及油源对比

Geochemical characteristics of oil and correlation of oil to source rock in ramp region of Wunan depression of Hailaer basin

对原油的物性特征、地球化学特征及油源进行精细分析,对乌尔逊凹陷油气勘探开发具有指导意义。乌南斜坡带原油具有低密度、低粘度、高含蜡量、高凝固点的物性特征及高饱和烃含量、低碳同位素值的地化特征,原油主要为形成于淡水-微咸水环境下的成熟油,成油母质中含有较多的陆源植物,并有一定数量的水生浮游生物及藻类。斜坡带铜钵庙组原油主要来自于铜钵庙组暗色泥岩;南屯组原油主要来自南屯组及大磨拐河组的暗色泥岩;大磨拐河组二段原油既有来自南屯组和铜钵庙组烃源岩的成熟油,又有来自大磨拐河组烃源岩的低熟油。

The physical properties of ramp region of the Wunan depression oil are low density, low viscosity, high wax content and high freezing point; and its geochemical characteristics are high content of saturated hydrocarbons and low value of carbon isotope. It is mainly mature oil formed in the fresh water-brackish water environment. There is a high content of land-based plants and a certain content of aquatic plankton and algae in the parent materials of the oil. According to the group composition, carbon isotope and the biomarker data comparison of the oil and source rocks in the study area, draw the conclusion that the crude oil of the Tongbomiao group are mainly comes from the dark claystone of the Tongbomiao group ; and the mother rocks of the Nantun crude oil are the dark claystone of the Nantun group and the Damoguaihe group; and the crude oil of the Damoguaiheer sector is a mixture of the mature oil which comes from the Nantun and Tongbomiao groups and the immature oil generated from the Damoguaihe group.