文档介绍：珠江口盆地白云凹陷珠海组碎屑岩储层特征及成因机制
摘要:通过岩石铸体薄片、粒度分析和压汞分析等手段,分析白云凹陷珠海组储层的岩石学特征和物性演化特征,研究沉积环境和成岩演化过程对储层特征的影响机制。研究结果表明:储层主要以长石质石英砂岩和长石岩屑质石英砂岩为主,颗粒支撑并以碳酸盐、自生石英和黏土矿物接触式胶结。储层物性总体具有中低孔中低渗特征,以粒间溶蚀扩大孔为主,其次为珠海组底部黏土膜保护的原生孔隙,分选好的中-粗喉型喉道使孔隙连通性良好;在凹陷西斜坡,珠海组上部和底部分别发育钙质砂岩夹层和铁泥质砂岩夹层。三角洲前缘环境是珠海组储层物性良好的先决条件;酸性流体的溶蚀溶解作用和绿泥石黏土膜保护是储层物性较好的根本原因,压实作用是粒间孔隙损失的主要原因,而部分储层渗透率较低是因为自生石英和黏土矿物充填喉道;钙质砂岩夹层物性差是胶结作用所致,而铁泥质砂岩夹层物性差是压实和胶结共同作用的结果。
关键词:次生孔隙;孔隙结构;成岩作用;沉积环境;成因机制;南海北部
中图分类号:﹢3 文献标志码:A
Reservoir characteristics of detrital sandstones in Zhuhai formation of Baiyun sag, Pearl River Mouth Basin
Abstract: Based on analyses of casting thin sections and particle size, mercury porosity measurements of the reservoir sandstones from Zhuhai formation of Baiyun sag,the petrography,pore types, pore throat structure, reservoir quality evolution, ic stage and diagenesis and their effects on reservoir quality were results show that reservoir sandstones mainly consist of Feldspathic quartz sandstone and feldspar lithic quartz grains are grain-supported and cemented by carbonate cements, authigenic quartz and clay minerals. Reservoir properties in general have medium low porosity and permeability,pores are mainly intergranular dissolved pores and the next is residual primary pores protect by clay film preserved in the bottom Zhuhai formation. Due to pore throats which are good sorted,pores show good connectivity In the western slope of the sag,calcareous sandstone and ferruginous and argillaceous sand bed are typically developed in the top and bottom of Zhuhai front deposits are the prerequisite for well reservoir quality of Zhuhai formation The dissolution of acidic fluid and intergranular pores protected by chlorite are major factors whose reservoir Quality is improved, compaction Is the main reason for the loss of intergranular pores in the buried history. Because of the filling of authigenic quartz and clay minerals in the throat,the part of the rese