【摘要】 依据定北5井、定北6井的岩心观察及常规薄片鉴定、薄片粒度分析资料,结合沉积史和区域地质特征,综合分析了下石盒子组-山西组砂岩的成岩作用类型及其特征,得出鄂尔多斯盆地定边北部地区上古生界主要的成岩作用有:压实、压溶作用,胶结作用,交代作用,蚀变作用,溶蚀作用,云母类矿物的水解作用;并分析了储层成岩演化特征以及对孔隙演化的影响。研究区上古生界储层从早成岩期到晚成岩A-B期的成岩演化过程中,所经历复杂的成岩作用极大地影响了岩石的孔隙度。溶蚀作用与蚀变作用是形成砂岩储层的两大建设性成岩作用,云母类矿物的水解作用对孔隙的形成也起到一定的积极作用;但机械压实、压溶作用和胶结作用则是储层形成过程中不可避免的破坏性成岩作用。更多还原

【Abstract】 This paper analyses the types and characteristics of the diagenesis of the Xiashihezi Formation and Shanxi Formation according to core observation,conventional thin-section identification,grain size analysis data of Well DB5 and Well DB6 in the north of Dingbian,in combination with the depositional history and regional geological characteristics of this region.It is recognized that the major diageneses of Upper Paleozoic in this region of Ordos Basin are: compaction and pressure solution;cementation;replacementation;alteration;dissolution;hydrolysis of mica.Porosity evolution influenced by those diageneses is also analyzed.The dissolution and alteration of feldspars and unstable rock fragments are the main constructive diageneses,but the compaction,pressure solution and cementation are the main destructive diageneses which are unavoidable.更多还原