东营凹陷南坡古近系红层砂体储层特征及控制因素

东营凹陷南坡古近系孔一段和沙四下亚段发育以水上氧化环境为主的碎屑岩沉积.针对红层砂体储集特征,综合应用岩心、薄片、X线、压汞等资料,分析岩石学、成岩作用及储集空间特征,研究控制储层物性的主要因素.结果表明:红层砂体岩石成分以长石、岩屑为主,主要经历早成岩A期至中成岩A2期的成岩作用,原生及次生孔隙是主要储集空间.储层物性受沉积作用和成岩作用影响,其中沉积作用控制储层原生孔隙,成岩过程经历碱性和酸性的流体环境,早成岩B期溶蚀作用最强,形成大量次生孔隙.综合沉积相、成岩相及构造特征将红层砂体划分为高孔中高渗型、中孔中渗型、中低孔中低渗型和低孔低渗型等4类储层,明确优质储层的发育规律.

Reservoir characteristic and control factors of paleogene red sandstones in southern slope of Dongying sag

There are many clastic sediments with oxidation environment outside water at the first member of Kongdian formation and the lower part of the fourth member of Shahejie formation in southern slope of Dongying sag.Based on comprehensive application of core,analysis and assay data of thin section X-ray diffraction and mercury intrusion porosimetry,we have carried out the research of the characteristics of petrology,diagenesis and reservoir space of redbeds sandstone,in order to research the main factors of controlling physical property.The petrographic composition of redbeds sandstones is mainly with feldspar and fragment,through the diagenesis from early diagenesis stage A to middle diagenesis stage A2,primary and secondary pore is the main reservoir space.The reservoir physical property is controlled by sedimentation and diagenesis.Sedimentation controlled the primary pore,diagenetic process go through the alkaline and acidic fluid environment,dissolution in the early diagenesis stage B is the most powerful,producing a lot of secondary pore,fracture improved reservoir permeability.Based on sedimentation and diagenesis,we have evaluated the reservoir classification,divided redbeds sandstone into four reservoir types,including high porosity and high-medium permeability,medium porosity and permeability,medium-low porosity and permeability and low porosity and permeability reservoir.