摘要
为探讨塔里木盆地原油类型和油源问题,运用色谱-同位素质谱分析技术,分析了该盆地塔中、塔北、塔东与库车地区的典型原油轻烃单体烃碳同位素组成。结果表明,不同结构轻烃化合物中,支链烷烃与环己烷系列比环戊烷系列更具明显的成因判识意义。2-甲基环戊烷2 mC_5、3-甲基环戊烷3 mC_5、3-甲基环己烷3 mC_6、环己烷CYC6与甲基环己烷mCYC_6等化合物的δ^(13)C在煤成油最高,δ^(13)C大于-21‰;湖相油次之,δ^(13)C位于-25‰^-22‰之间;再次之为寒武系-下奥陶统海相原油,δ^(13)C位于-27‰^-21‰之间,最轻的为上奥陶统海相原油,δ^(13)C小于-28‰。其碳同位素值可以较好的判别该盆地寒武系-下奥陶统海相油、上奥陶统海相油、湖相油与煤成油。优选的8个特征化合物碳同位素可以作为原油成因类型的划分标志,尤其是2-甲基环戊烷2 mC_5、3-甲基环戊烷3 mC_5、3-甲基环己烷3 mC_6、环己烷CYC6与甲基环己烷mCYC_6等化合物。特征轻烃化合物的碳同位素组成可成为不同成因原油的划分标志。
A large number of crude oil,include marine,lacustrine and coal-formed oils,were found in the Tarim Basin,a typical superimposed basin. By using the GC-IRMS technique,compound-specific carbon isotope compositions of light hydrocarbons in crude oils from the Tazhong,Tabei,Tadong areas and the Kuche depression were investigated. Carbon isotopic compositions of branched alkanes and cyclohexane compounds are more robust than cyclopentane compounds in tracing the source of crude oil. For the compound2 mC5,3 mC5,3 mC6,CYC6 and mCYC6,carbon isotopic compositions of in coal-formed oils are highest（ 〉-21‰）,lacustrine oils from-25‰ to-22‰,marine oils from Cambriam-early Ordovician strata in the range of-27‰ to-21‰,while carbon isotopic compositions of marine oils from late Ordovician are lowest（〈 -28‰）. Thus,crude oil derived from Cambriam-early Ordovician and late Ordovician strata and coal-formed oil can be well distinguished by δ^13C values of branched alkanes and cyclohexane compounds. Eight characteristic compounds,especially 2 mC5,3 mC5,3 mC6,CYC6 and mCYC6,could be selected as indexes to discriminate crude oil origin. It is thus suggested that the Compound-specific carbon isotope can be a marker to distinguish crude oil source.
出处
《矿物岩石地球化学通报》
CSCD
北大核心
2017年第4期667-672,共6页
Bulletin of Mineralogy, Petrology and Geochemistry
基金
湖北省自然科学基金项目(2015CFC856)
高等学校博士学科点专项科研基金新教师类资助课题(20124220120001)
油气资源与勘探技术教育部重点实验室开放基金项目(K2015-19)
关键词
塔里木盆地
原油
地球化学
轻烃
碳同位素
Tarim Basin
Crude oil
Geochemistry
Light hydrocarbon
Carbon isotope
