【摘要】 通过对延长统长 8段厚层砂岩沉积岩石学和层序地层学研究 ,将其分为两类 ,一类是由多期单一成因的分流河道砂岩叠加构成 ;另一类是由三角洲前缘的水下分流河道、河口坝、坝顶席状砂和滑塌砂等多种沉积微相以不同的组合形式叠加构成。首次提出在“高可容纳空间 ,高沉积通量”背景下 ,只有经过特殊水动力条件 (淘洗 )改造后形成的被我们称之为坝顶席状砂的砂岩才有可能成为相对高孔、高渗的优质储层。更多还原

【Abstract】 The thick sandstones in Chang 8 oil Formation of Yanchang group may be divided into two types by the research on sedimentary petrology and sequence stratigraphy. One is made up of single genetic distributary channel sandstones that is stacked with multiple stages sandstone. The other is consist with many microfacies , including underwater distributary channel, river mouth bar, sheet sand over mouth bar and slump sandstone. They pile up as thick sandbody by different stacking patterns. It has been first proposed that only the sandstone called as sheet sand over mouth bar may become high-quality reservoir with relative high porosity and permeability under the background of high accommodations and high sediment alimentations.更多还原