鄂尔多斯盆地冯地坑-洪德地区长4+5段储层以长石砂岩和岩屑长石砂岩为主.本文通过岩心观察、薄片鉴定、扫描电镜、粘土矿物分析等,研究延长组长4+5段的成岩作用特征,分析其对储层物性的影响,确定储层砂岩的成岩作用阶段.早成岩期的压实作用和多种矿物的胶结作用是造成本区岩石孔隙体积减少的重要因素,而溶解作用尤其是长石的溶蚀作用是储层变好的重要控制因素.%The Chang 4 +5 reservoirs in the Fengdikeng-Hongde region , Ordos Basin are dominantly composed of lithic feldspathic and feldspathic sandstones. The present paper deals, on the basis of cores, thin sections, SEM and clay minerals, with the diagenesis of the reservoir sandstones from the Chang 4 +5 member of the Yanchang Formation and its affeccs on the reservoir physical properties. The compaction and mineral cementation during the early diagenetic phase are main controlling factors for the reduction of the porosity volumes of the reservoir sandstones, whereas dissolution of framework grains especially the dissolution of feldspar during the late diagenetic phase is interpreted as the key diagenetic controls for the formation of the excellent reservoirs.
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