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中国湖相原油大多以高含蜡为特点,如泌阳凹陷、南阳凹陷和大民屯凹陷的特高蜡原油。普遍认为,原油中石蜡,主要是长链(>C_(22))正构烷烃,来源于高等植物蜡质或角质、孢粉质等成分。但是,有机岩石学分析表明中国典型的深湖-半深湖相生油岩中占绝对优势的生油组分是层状藻类体、结构藻类体和腐泥无定形体。这使我们想到某些湖相藻类体很有可能作为高蜡油母质,泌阳凹陷是我国典型的小而肥含油气盆地,面积约1000 km~2,其原油含蜡量为24.26％～40.27％。凹陷中主力生油层为下第三系深湖半深湖相核桃园组,有机质类型以Ⅰ型为主,成油条件十分优越。本项研究通过对泌阳凹陷核桃园组生油岩生油组分有机岩石学剖析、典型生油组分盘星藻藻类体热解气相色谱-质谱、加水热模拟产物分子地球化学和同位素地球化学四个方面分析,表明藻类体是泌阳凹陷生油岩中占绝对优势的生油组分,湖相绿藻藻类体(如盘星藻)中藻质素是高蜡油的重要母质。
Most lacustrine crude oil in China is characterized by high wax content, such as the extra-high wax crude oil in Biyang Depression, Nanyang Depression and Damintun Depression. It is generally believed that the paraffin in crude oil, mainly long chain (> C 22) n-alkanes, is derived from higher plant waxes, keratin, sporoplasm and other ingredients. However, the organic petrological analysis shows that the oil components that dominate the deep-half-deep lacustrine source rocks in China are layered algae, structural algae and sapropelite. This reminds us that some lacustrine algae are likely to be high waxy parent materials. Biyang depression is a typical small and fat petroliferous basin in China with an area of 1000 km ~ 2 and a wax content of 24.26% ~ 40.27 %. The main oil layer in the depression is the Lower Tertiary deep lake half-deep lacustrine core Taoyuan Formation. The organic matter type is mainly type I, and the oil-forming conditions are extremely superior. In this study, the organic petrological analysis of the source rocks of the Hetaoyuan Formation in the Biyang Depression, the pyrolysis gas chromatography-mass spectrometry of typical oil-producing algae, and the molecular and geochemical The analysis of the four aspects shows that algae are the most abundant oil components in the source rock of the Biyang sag. Algae is an important parent material of high wax oil in the lacustrine green algae (such as Platymonas sp.).