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芳烃化合物是原油和烃源岩抽提物中的主要馏分,经过小型氧化铝两步层析法,可以得到分离度高的二环芳烃和三环芳烃化合物.塔里木油田不同地区的上奥陶统烃源岩和寒武系‐下奥陶统烃源岩抽提物芳烃馏分的GC-IRMS分析表明芳烃单体烃碳同位素组成除受热演化程度影响外,还受有机质来源、沉积环境和成烃过程的影响.无论是烷基萘、烷基联苯、烷基菲的亚系列,还是单体化合物,如1-甲基菲、9-甲基菲、2,6-二甲基菲等的δ13C值均表现为寒武系‐下奥陶统烃源岩偏重,两套烃源岩之间亚系列的δ13C差值最高可达16.1‰,单体烃之间差值可达14‰.综合塔里木盆地不同时代烃源岩和原油的生物标志物组合特征及单体烃的碳同位素组成,可为油源对比提供强有力的佐证.塔中地区大部分奥陶系原油9-甲基菲具有偏负的δ13C组成,贫伽玛蜡烷,富含升藿烷,主要来自于上奥陶统烃源岩;而塔东地区原油和部分塔中地区原油富伽玛蜡烷、贫升藿烷,9-甲基菲的δ13C组成明显较重,表明其主力油源岩为寒武系‐下奥陶统烃源岩.
Aromatic compounds are the main fractions of the crude oil and the source rock extract, and can be obtained by the two-step mini-alumina chromatography of the highly separated di- and tricyclic aromatic hydrocarbons. The Upper Ordovician GC-IRMS analysis of aromatics fractions from source rock and Cambrian-Lower Ordovician hydrocarbon source rock extract shows that carbon isotopic compositions of aromatics are affected by the source of thermal evolution, sedimentary environment and hydrocarbon generation Whether it is alkyl naphthalene, alkyl biphenyls, alkyl phenanthrene sub series, or monomeric compounds such as 1-methyl phenanthrene, 9-methyl phenanthrene, 2,6-dimethyl phenanthrene, etc. δ13C Values show that the Cambrian-Lower Ordovician source rocks are heavily weighted, and the δ13C difference between the two sets of source rocks is up to 16.1 ‰ and the difference between monomer hydrocarbons is up to 14 ‰. Comprehensive Tarim The biomarker assemblages of hydrocarbon source rocks and crude oils from different ages in the basin and the carbon isotopic composition of the hydrocarbon can provide powerful evidence for the comparison of oil sources. Most of Ordovician crude oil in Tazhong area have partial Negative δ13C composition, poor Gamalin, rich in hopane, mainly from the upper Ordovician Source rocks. However, δ13C of the crude oil in Tarong area and part of the Tazhong area is obviously heavier, indicating that the main source rocks are Cambrian-Lower Ordovician source rocks.