塔北隆起轮东地区奥陶系原油地球化学特征

Geochemical Characteristics of Ordovician Crude Oil in Lundong Area of Northern Tabei Uplift

通过对轮东地区奥陶系原油样品系统地全油色谱和色谱-质谱分析,剖析了该区奥陶系原油的地球化学特征,对原油的组成特征﹑母质来源及成熟度等方面进行了探讨。研究表明,该区的原油有2类,第1类原油的地球化学特征是重排甾烷相对丰度较低﹑C28-规则甾烷含量高﹑甲藻甾烷和4-甲基甾烷较发育,其对应的萜烷类的分布特征是三环萜烷相对丰度较低﹑藿烷总体浓度较高和较高含量的伽马蜡烷;第2类原油的地球化学特征则相反。这2类原油均来源于海相还原沉积环境,其中第2类原油的成熟度较高。原油的这2种分布特征差异主要反映了它们在来源特征上的差异。

By using the analytical techniques of GC,GC/MS,this paper studies the geochemical characteristics and discusses the composition,source rock and maturity of the crude oil.The study result indicates that the crude oil in Lundong Area can be divided into 2genetic groups.The geochemical characteristics of the first crude oil are low contents of diasterane,tricyclic terpane and high abundance of C28 sterane,dinoflagellates sterane,4-methyl sterane,hopane and gammacerne.While the geochemical characteristics of the other crude oil are opposite.Both of these crude oils are from marine depositional environment.And the second group of crude oil is at high mature stage.The difference of the distribution mainly indicates the diversity of the original resource.