【摘要】 为了明确北部湾盆地乌石凹陷东部原油母质来源、沉积环境、成熟度以及可能烃源层,运用色谱-质谱技术对其原油样品的芳香烃组成进行了系统的研究。结果表明,乌石凹陷东部原油芳香烃整体表现为高萘、高菲系列,低联苯、低三芴和低芳香甾烷系列的特征;1,2,5,6-四甲基萘、惹烯以及三芴、三芳甾烷系列均指示母质具有低等水生生物和陆源高等植物双重贡献,形成于淡水—微咸水湖相的还原及弱还原—弱氧化环境;用甲基二苯并噻吩比值、四甲基萘比值、甲基菲指数、甲基菲分布分数和甲基二苯并噻吩分布指数分别计算的镜质体反射率,均表明原油为中等成熟的原油。根据原油芳香烃组成,研究区原油可以划分为2大类3小类:Ⅰ类原油来源于流沙港组流二段上亚段和下亚段烃源岩;Ⅱ1类原油主要来源于流二段下亚段烃源岩;Ⅱ2类原油除流二段下亚段烃源岩外,可能还有流三段烃源岩的贡献。更多还原

【Abstract】 In order to identify the oil source, depositional environment, thermal maturity and possible source rocks of the oil in easternWushi sag of Beibu Gulf basin, chromatography and mess-spectrometric techniques are used to systematically analyze aromatic hydrocar-bon compositions in oil samples. The results show that aromatic hydrocarbon in the oil of eastern Wushi sag is characterized by high contentof aphthalene and phenanthrene series, low content of biphenyl, threefluorene and triaromaticsterane series. Compositions such as 1,2,5,6methyl naphthalene, retene and triaromatic sterane indicate that the organic matters in the source rocks are of double contributions from bothaquatic organisms and terrestrial higher plants and form in reduction and weak reduction-weak oxidation environments of fresh water-salinewater lacustrine facies. Vitrinite reflectances obtained from methyldibenzothiophenes ratio and distribution index, methyl naphthalene ratio,methylphenanthrene index and distribution fraction respectively show that the crude oil belongs to moderate maturity oil. Based on the com-positions of aromatic hydrocarbons in the oil, the oil in the study area can be divided into 3 subgroups of 2 types, which includes type Ⅰ oiloriginated from the source rocks of the upper and lower El2; type Ⅱ1oil from the lower El2 and type Ⅱ2oil from the lower El2 and possibly El3.更多还原