【摘要】 对南八仙油气藏E13 与N22 —N1油层油气地球化学特征和油源的关系进行了分析 ,根据油气分异作用与其组成变化的相互关系研究了该油气藏的蒸发分馏作用 ,并从地质构造背景和油气及其烃源岩地化特征方面探讨了其成因机制。研究结果表明 ,虽然南八仙油气藏E13 与N22 —N1两层系的原油对比表明两者是同源 ,但它们在轻烃组成和正构烷烃系列分布上存在显著差异。E13 原油轻烃中正烷烃含量很少 ,而芳烃化合物含量异常高 ,其正烷烃摩尔分数对数曲线为折点在nC10 的折线 ,表明其经历了强烈的蒸发分馏作用。而N22 —N1原油轻烃中正烷烃占优势 ,高碳数化合物较少 ,说明该层原油是从E13 油气层通过蒸发分馏作用向上运移而来。该含油气构造带的断裂系统和高成熟的油气及其煤系烃源岩是导致蒸发分馏作用的主控因素更多还原

【Abstract】 The geo?_chemical characteristics and genetic origins of crude oil and gas of E 1 3 layer in Nanbaxian Reservoir were compared with those of N 2 2 and N 1 layers.Based on the relationship between fractionation and compositional alteration of oil and gas,the evaporative fractionation in Nanbaxian Reservoir was analyzed.The genetic mechanism of the reservoir was investigated,according to the geological setting and geo?_chemical features of hydrocarbon and source rocks.The research result shows a significant difference presented in their compositions of light hydrocarbon and distribution of n_alkane homologues,though crude oils of E 1 3,N 2 2 and N 1 layers in Nanbaxian Reservoir have the same genetic origin.The nC 5-nC 9 light hydrocarbon of crude oil in E 1 3 layer was depleted in n_alkanes and remarkably rich in aromatic compounds.The distribution curve of log molar fraction for n_alkanes has a slope break at C 10 point,which suggests that the evaporative fractionation happened in this reservoir.Whereas,the crude oils from N 2 2 and N 1 layers comtain light hydrocarbon dominated by n_alkanes and low amount of high molecular weight n_alkanes,which shows that the oils of N 2 2 and N 1 layers were derived from E 1 3 layer by evaporative fractionation.The petroliferous faults in the reservoir and high maturity of hydrocarbon and coal_bearing source rocks are the main factors for controlling the evaporative fractionation.更多还原