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南堡凹陷为环渤海湾盆地一个小而富油的生烃凹陷,勘探前景极为广阔,其中沙三段四亚段(Es43)泥岩厚度大,分布范围广,为研究区最主要的烃源岩之一。通过对Es43段烃源岩的有机岩石学与有机地球化学常规分析,对该套烃源岩系统的研究与评价,并且结合原油与烃源岩的生物标志化合物的对比与分析,探讨其油源贡献。研究结果表明,Es43段部分层段生烃条件较好,有机质丰度与类型达到好烃源岩标准,依据生物标志化合物特征划分为2类,第一类烃源岩处于成熟阶段,主要形成于淡水的还原环境,生源构成为混合型,以低等水生生物和高等植物混源贡献为主;第二类烃源岩处于未熟—低熟阶段,主要形成于淡水氧化环境,以陆源高等植物输入为主,对油气贡献较少。油源对比结果表明,南堡凹陷高柳地区沙河街组的原油主要来源于Es43段第一类烃源岩。
The Nanpu sag is a small and oil-rich hydrocarbon generating depression in the Bohai Gulf Basin with a vast exploration prospect. The Es43 mudstone of the Es3 is large in thickness and widely distributed, which is the most important source rock in the study area one. Based on the conventional analysis of organic petrology and organic geochemistry of Es43 source rocks, the study and evaluation of this set of source rock systems, and the comparison and analysis of biomarkers of crude oil and source rocks, contribution. The results show that the hydrocarbon generation conditions are good in some intervals of Es43, and the abundance and type of organic matter meet well with source rock standards. According to the characteristics of biomarker compounds, the hydrocarbon generation conditions are divided into two types. The first type of source rocks are in mature stage, Freshwater environment, the source composition of a mixed type, with lower aquatic organisms and mixed contribution of higher plants; the second type of source rock in the immature - low-maturity stage, mainly formed in freshwater oxidation environment, Mainly less contribution to oil and gas. The results of oil source comparison show that the crude oil of Shahejie Formation in Gaoliu area of Nanpu sag mainly comes from the first type of source rocks in Es43.