冀中坳陷束鹿凹陷潜山原油地球化学特征与油源对比

Geochemical Characteristics and Oil-Source Correlation of Crude Oils of Buried Hills in Shulu Sag,Jizhong Depression

为了探究束鹿凹陷潜山油藏的油气来源,利用聚类分析方法对主要烃源岩进行了精细划分,并通过生物标志化合物和油-岩成熟度对比,实现了潜山油源的精细对比.结果表明,潜山原油的地球化学特征总体相似,来自同一套烃源岩.Es1x烃源岩有机质以藻类和浮游生物输入为主,沉积于咸水、强还原环境,处于未熟-低成熟阶段,而E_(s3)^(x)烃源岩有机质以浮游生物和高等植物混合输入为主,沉积于淡水-微咸水、弱氧化-弱还原环境,成熟度随深度增加而增大,可细分为A、B、C、D四种类型,其中D类是最好的类型.油源对比表明,潜山原油主要来源于E_(s3)^(x)烃源岩,其中斜坡潜山原油主要来源于洼槽边缘浅层低成熟E_(s3)^(x)烃源岩,而洼中隆潜山原油主要来源于洼槽中心深层高-过成熟E_(s3)^(x)烃源岩.

In order to investigate the oil and gas sources of buried hill reservoirs in Shulu sag,the hierarchical cluster analysis(HCA)is used to divide the main source rock,and oil-source correlation is achieved through the comparison of biomarker and oilrock maturity.The results show that the buried hill oils have similar geochemical characteristics on the whole,indicating that they come from the same set of source rock.The organic matter of E_(s3)^(x)source rock is dominated by algae and plankton,which is deposited in salt water and strong reduction environment and is in the stage of immature to low maturity.While the organic matter of E_(s3)^(x)source rock is mainly mixed input of plankton and higher plants,which is deposited in fresh-brine water,weak-oxidation and weak-reduction environment,and its maturity increases with the increase of depth.The E_(s3)^(x)source rock is further subdivided into four types:A,B,C,and D,and type D is the most favorable type.Comparison of biomarker and oil-rock maturity indicate that crude oils in buried hill reservoirs are mainly derived from E_(s3)^(x)source rock,of which oils in the slope buried hill are mainly derived from shallow low-mature E_(s3)^(x)source rock at the edge of the depression,and oils in the high-in-sag are mainly derived from deep high-over mature E_(s3)^(x)source rock in the center of the depression.