渤海湾盆地南堡凹陷滩海地区原油来源及勘探潜力分析

Analysis of Crude Oil Source and Exploration Potential of Offshore Area in Nanpu Sag of Bohaiwan Basin

通过原油基本特征的分析,从生标物特征角度对南堡凹陷的原油类型进行了划分,进而结合烃源岩发育特征分析了滩海地区的油气勘探潜力。南堡凹陷的原油分为A、B、C共3种类型,A类原油根据生标物特征差异又分为A1、A2两个亚类,分别来自沙三段(Es3)烃源岩和东三段(Ed3)烃源岩,主要分布在陆上。B和C两大类原油主要分布在滩海地区,均为成熟原油。B类原油的典型特征是伽马蜡烷含量低,主要来自Ed3烃源岩,沙一段烃源岩有少量贡献;C类原油的伽马蜡烷含量高,主要来自沙三段烃源岩。滩海地区的各层段烃源岩都比较发育,演化程度高,中深层具有较好的轻质油和天然气勘探潜力。

Based on the features of crude oil and biomarkers,crude oil types were divided and in combination with source rock development characteristics,oil-gas exploration potential was discussed in offshore area.Totally,crude oil in Nanpu Sag was divided into 3 types of A,B and C.Furthermore,Type A was divided into two types of A1 and A2 whose source rocks are respectively from the third member of Shahejie Formation and the third member of Dongying Formation and distributed chiefly on land.Types B and C wereE mature and distributed mainly in offshore area.Type B comes from the source rock of the third member of Dongying Formation and has lower Gammacerane content.Type C come forms the source rock of the third member of Dongying Formation and has higher Gammacerane content.In the offshore area,different layers of source rocks are developed and have higher maturity and there is better exploration potential of light oil and natural gas in the middle-deep formations.