轮南14井原油正构烷烃和类异戊二烯单体碳同位素研究

Study on Stable Carbon Isotopic Compositions of n-alkanes and Isoprenoids for Crude Oils from Well Lunnan 14, Tarim Basin

通过对轮南 14井正构烷烃和类异戊二烯烃的单体碳同位素分析 ,证实该井奥陶系和石炭系油藏具有相同或相似的油源 ,而三叠系油藏与奥陶系、石炭系油藏具有较大的碳同位素差异 ,反映其油源不同。在奥陶系、石炭系和三叠系油藏中 ,均呈现出类异戊二烯烃碳同位素值略重于同碳数正构烷烃的特征 ,结合前人研究成果 。

Compound-specific stable carbon isotope analysis of n-alkanes and isoprenoids were conducted for crude oils from Well Lunnan 14, Lunnan oilfield, Tarim Basin, NW China. It can be seen that the crude oils from the Ordovician and Carboniferous productive horizons shared the same organic matter inputs while the Triassic crude oil had different sources of organic matter input. In addition, the carbon isotope composition of isoprenoids is isotopically heavier than that of n-alkanes with the same carbon number. It is presumed that the biosynthesis pathway and intramolecular distribution of 13C might theoretically account for the recognized relationship between n-alkanes and isoprenoids in terms of carbon isotope compositions.