基于扫描电镜的砂岩储层分析:以白云凹陷珠江组三角洲前缘砂体为例

Analysis on the sandstone reservoir by SEM:A case study of the delta front sand body of Zhujiang Formation,Baiyun Sag

本文通过扫描电镜和铸体薄片观察并结合X射线衍射和压汞分析对珠江口盆地白云凹陷珠江组岩屑砂岩储层的孔隙结构、矿物组成进行了分析,结果表明:珠江组岩屑砂岩储层发育有原生孔隙和次生孔隙,储层平均孔隙度12.3%,属于物性良好的油气储层。储层中原生孔隙发育较差,孔隙组成以次生孔隙为主,次生孔隙中溶孔和铸模孔构成了储层主要孔容,为油气主要富集渗流场所。储层自生矿物包括粘土矿物、次生石英加大、黄铁矿和片沸石等,粘土矿物为主要自生矿物,其发育程度与储层孔隙度呈负相关性。

This paper analyses the pore structure of lithic sandstone reservoir and mineral composition of Zhujiang Formation of Pearl River mouth basin by means of observing the scanning electron microscope and the casting thin sections, XRD and the analysis of mercury intrusion. The result shows that the reservoir development of Zhujiang Formation of Pearl River mouth basin has two kinds of pore： primary pore and secondary pore. The average porosity of reservoir is 12. 3% , which belongs to the oil and gas reservoir of high quality. The development of primary pore in reservoir is poor. The pore composition is given priority to secondary pore, in which the dissolution pore and mold pore constitute the main entrance which provides the main seepage places of oil gas. Reservoir＇ s authentic mineral includes clay minerals, secondary reservoir and heulandites quartz and pyrite, etc. Clay mineral is the main authigenie mineral, and its development degree has a negative correlation with the reservoir porosity.