鄂尔多斯盆地东北部太原组砂岩储层特征

根据岩心与铸体薄片观察、扫描电镜观测及岩石矿物学、物性资料分析，研究了鄂尔多斯盆地东北部地区太原组砂岩储层特征及影响因素。研究区储层的岩石类型以粗粒岩屑石英砂岩为主．成分成熟度好，结构成熟度中等一好，储层物性差，属于低孔、低渗储层，储集空间以次生孔隙为主，发育极少的成岩裂隙对改善储层渗透性贡献不大。储层的储集性受沉积相和成岩作用综合控制。沉积作用分析表明潮坪潮道砂体是最有利储层发育的沉积微相；压实作用、胶结作用、溶蚀作用控制了储层孔隙演化，其中压实作用是导致原始孔隙损失的主要原因，硅质胶结与自生伊利石进一步降低了孔隙度与渗透率，碳酸盐的胶结作用持续到了晚成岩A期，早期胶结增强了岩石抗压实能力，晚期胶结充填则损害次生孔隙。

Sandstone reservoir characteristics of Taiyuan Formation in northeastern Ordos Basin

Based on analysis of cores, cast thin section, scanning electron microscope, mineral and physical properties, the sandstone reservoir characteristics and its influencing factors of Taiyuan Formation in northeastern Ordos Basin are studied. The lithology of the reservoir in the study area is mainly sublitharenite, with high compositional maturity, middle-high textural maturity and poor properties. It is low porosity and low permeability reservoir. The reservoir space is dominated by secondary pore. The rarely developed diagenetie mierofractures made little contribution to improving the reservoir permeability. The reservoir quality is controlled by sedimentary facies and diagenesis. Sedimentological analysis shows that tidal channel is the favorable sedimentary microfacles of reservoir. Reservoir pore evolution is dominated by compaction, cementation and denudation. The decrease of sandstone porosity is mainly caused by compaction. Siliceous cementation and authigenie illite further reduced the porosity and permeability. Carbonate cementation continued to late diagenetic A stage. The cementation in the early stage enhanced the preservation of primary pores, and the cementation in the late stage damaged secondary pore.