原油单体烃类的碳同位素组成研究

本文利用新兴的原油单体烃类在线同位素分析技术测定了塔里木盆地原油及凝析油的正构烷烃、轻烃部分的异构烷烃和植烷、姥鲛烷的稳定碳同位素值，根据原油单体烃的碳同位素分布，并结合地质情况，将塔里木盆地原油分为源于下古生界，上古生界，中新生界和上述源岩混源的４种成因类型，并确认塔里木盆地是一个以下古生界油源为主的多油源的复合含油气盆地。本文还对原油单体烃碳同位素分布特征及成因等问题进行了初步探讨。

AN ON-LINE CARBON ISOTOPE STUDY OF HYDROCARBON MONOMERS IN CRUDE OILS FROM TARIM BASIN

Using GC/C/MS on-line carbon isotope analysis technique, we obtained the stable carbon isotope ratios of n-alkanes, iso-alkanes from the light hydrocarbon compositions and pristane, phytane in crude oils in Tarim basin. According to the carbon isotope distribution in the hydrocarbon monomers and geological conditions, crude oils from the Tarim basin can be divided into four genetic types, i. e. oils sourced from Lower Paleozoic (type A), from Upper Paleozoic (type B), from terrestrial source rocks of Mesozoic and Cenozoic Erathems (type C) and mixed oil from Lower Paleozoic and other strata (type D). According to the results of carbon isotope analysis, we conclude that crude oils from the Tarim basin are derived from multiple source rocks, of which Lower Paleozoic Erathem's played an essential role. In addition, the genesis of carbon isotope distribution of hydrocarbon monomers is discussed preliminarily, it is found that the maturity had an effect on the carbon isotope distribution of hydrocarbon monomers in crude oil.