不同沉积环境原油轻烃单体烃碳同位素组成特征

large number of crude oil from different sedimentary environments in Tarim and Tuha Basin were analysed by GC-IRMS. Compound-specific carbon isotope compositions of light hydrocarbons in crude oils from different sedimentary environments were investigated. It has been suggested that compound-specific carbon isotope of branched alkanes(2mC5,3mC5 and 3mC6) and cyclohexane compounds(CYC6 and mCYC6) Show significant difference in marine oil, lacustrine oil and coal-formed oil. Because of paticularity of organic matter in Tuha Basin, the δ13C of branched alkanes and cyclohexane compounds in coal-formed oils from Tuha Basin were less than lacustrine oil and coal-formed oil from Tarim Basin. Compound-specific carbon isotope composition of mCYC6 was established to distinguish between marine oil and continental oil. δ13 CmCYC6 is greater than -25‰ in continental oil and less than -25‰ in marine oil. It was adviesd that the δ13 CmCYC6 can be used to identify marine oil, lacustrine oil and coal-formed oil in Tarim Basin.