泌阳凹陷双河油田原油地球化学特征及精细油—源对比研究

Geochemistry and oil-source rock correlations in the Shuanghe oilfield,Biyang sag,Nanxiang basin

以双河油田典型原油样品为基础,采用气相色谱—质谱分析技术(GC-MS),通过多种生物标志物参数对比和色谱图特征分析,对核二段、核三段共计28个原油样品做详细的地球化学特征描述和精细油—源对比。分析结果表明,双河油田核三上亚段原油饱和烃色谱图为前峰型和双峰型,重排甾烷和三环萜烷的相对含量较低;而核三下亚段原油饱和烃色谱图主要为前峰型,重排甾烷和三环萜烷的相对含量较高;核三段原油C19、C20、C21三环萜烷呈上升型分布,伽马蜡烷含量较高,C27~C29规则甾烷以“V”字型分布为主。核二段和核三段原油,陆源高等植物和低等水生生物均有贡献,且沉积环境较还原,核三下亚段原油成熟度明显高于核三上亚段原油,因此最终确定核三下亚段原油主要来源于核三下亚段烃源岩,而核三上亚段原油则为核三上亚段和核三下亚段烃源岩的混源油。

In this paper the authors mainly studied geochemical characteristics and oil- source rock correlations of28 oil samples from the Shuanghe oilfield based on the gas chromatography-mass spectrometry and biomarkers.The results indicate that the peaks of C19 ,C20 ,C21 - tricyclic terpanes gradually rise and the peaks of C27 ~C29 steranes are characterized by "V" shape of crude oils in the Shuanghe Oilfield.Besides, the concentration of gammacerane is high.The peak shapes of saturates are characterized by "prepeak" and "double peak",and the relative values of diasteranes and tricyclic terpanes are low in oils from upper layer of the Eh3 member.However,the peak shapes of saturates are characterized by "prepeak" and the relative content of diasteranes and tricyclic terpanes is high in oils from lower layer of the Eh3 member.For both the oils of Eh2 member and Eh3 member,the sedimentary environments are reductive and are sourced from higher plant and aquatic organism. However,the maturity of the oil from lower layer of Eh3 member is significantly higher than that of the oil from the upper layer of Eh3 member.In conclusion,the oils from the lower layer of Eh3 member are mainly sourced from the lower layer of Eh3 member,and the oils from the upper layer of Eh3 member are sourced from lower and upper layer of Eh3 member.