渤海湾盆地济阳坳陷泥页岩岩相与页岩油富集关系

Genetic connection between mud shale lithofacies and shale oil enrichment in Jiyang Depression,Bohai Bay Basin

利用显微镜、氩离子抛光、核磁共振、电子扫描显微镜及生排烃模拟等技术手段,以渤海湾盆地济阳坳陷泥页岩为例,剖析不同泥页岩岩相储集性、含油性和页岩油可动性特征。分析了岩相类型与页岩油富集的相关关系。依据岩石组分、沉积构造和有机质丰度,建立了济阳坳陷古近系沙河街组四段上亚段—沙河街组三段下亚段泥页岩岩相划分标准。研究区目的层段主要发育6类泥页岩岩相,其中机械搬运沉积和化学作用沉积交替形成的富有机质纹层状岩相TOC、S1、含油饱和度、可动油饱和度、低碳轻质组分含量及生排油率最高,其储集空间类型多、孔隙发育,还发育有机质网络体系和层间微裂缝体系,其为油气输导的高速通道,因此最有利于页岩油富集。

By using microscope,argon ion polishing technology,nuclear magnetic resonance（NMR）,scanning electron microscopy,and hydrocarbon generation and expulsion simulation,reservoir properties,oiliness and shale oil mobility of different mud shale lithofacies were examined with the mud shale in Jiyang Depression,Bohai Bay Basin as the example.The relationship between lithofacies type and shale oil enrichment was analyzed.Based on the rock composition,sedimentary structures and abundance of organic matter,a mud shale lithofacies classification standard for the upper submember of the 4th Member to the lower submember of the 3rd Member of Paleogene Shahejie Formation（Es4s-Es3x） was established.Six lithofacies are developed in the target formation,in which the laminar organic-rich lithofacies formed in the alternating mechanical transportation deposition and chemical deposition,not only has the highest TOC,S1,oil saturation,movable oil saturation,content of low-carbon light components and oil generation and expulsion rate,but also has various types of reservoir space,abundant pores,and organic network system and interlayer micro-fracture system which can serve as high-speed channels for shale oil and gas migration,so this lithofacies is favorable for shale oil enrichment.