标题:
不同沉积环境原油轻烃单体烃碳同位素组成特征Characteristics of Carbon Isotope Composition of Light Hydrocarbon Monomer Hydrocarbon of Crude Oils in Different Sedimentary Environments
作者:
李洪波, 张敏
关键字:
曲流河;沉积微相;复合砂体;剩余油挖潜Meandering river; sedimentary microfacies; compound sand body; remaining oil
期刊名称:
《Journal of Oil and Gas Technology》, Vol.38 No.3, 2016-09-30
摘要:
对塔里木盆地与吐哈盆地不同沉积环境原油进行了全烃色谱–同位素质谱检测分析，获得了轻烃单体烃碳同位素组成，据此剖析了其地球化学特征。研究表明，支链烷烃与环己烷和甲基环己烷的碳同位素在海相油、湖相油与煤成油中呈现显著差异性。由于不同盆地有机质特征不同，吐哈盆地煤成油在上述化合物中的碳同位素值(δ13C)小于塔里木盆地的湖相油与煤成油。以mCYC6的δ13C值作为海、陆相原油的典型区分标志，大于−25‰为陆相油，小于−25‰为海相油。针对塔里木盆地而言，陆相原油中mCYC6的δ13C大于−20‰可作为煤成油的鉴别标志，位于−22‰~−20‰之间可作为湖相油鉴别标志。
Large amounts of crude oil from different sedimentary environments in Tarim and Tuha Basin were analyzed by GC-IRMS. The composition of light hydrocarbon and monomer hydrocarbon isotope was obtained, by which its chemical characteristics were analyzed. Study indicates that the carbon isotopic compositions of branched alkanes and cyclohexane and methyl cyclohexane show significant difference in marine oil, lacustrine oil and coal oil. Because of particularity of organic matter in Tuha Basin, the δ13C of branched alkanes and cyclohexane compounds in coal-formed oils from Tuha Basin was less than that in 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. is greater than −25‰ in continental oil and less than −25‰ in marine oil. In Tarim Basin, the δ13C value of mCYC6 in terrigenous crude oils that is higher than −20‰ can be taken as the marker for identifying coal derived oil, while the δ13C value of mCYC6 between −22‰ - −20‰ can used as the marker for identifying lacustrine oil.