南江地区震旦系灯影组白云岩优质储层主要为潮坪或粒屑滩环境成因的藻白云岩、粒屑白云岩和重结晶成因的粉-细晶白云岩,现存储集空间都是与溶解作用和重结晶作用相关的晶间(溶)孔、粒间溶孔、特大溶孔、缝合线溶孔和残余岩溶孔洞等。通过对原生和后生控制因素研究表明,灯影组优质储层是经过5个演化阶段后的最终产物,主控因素为表生期大气淡水岩溶作用及深埋期埋藏溶蚀作用。原始的沉积微相和岩石类型控制着岩溶作用的强度,埋藏溶蚀作用主要是对岩溶孔洞进行溶蚀扩大或充填破坏。
The high-quality dolomite reservoir of Dengying Formation,Sinian,Nanjiang area,is composed of algal dolomite and grain dolomite formed at tidal flat or grain bank facies,silt-fine crystalline dolostones resulted by recrystallization.The existing porosity types are basically secondary pores related to the dissolution and recrystallization,which are inter-crystal(dissolution) pores,inter-particle dissolution pores,great dissolution pores,stylolite dissolution pores,and lots of survivals karst cavities etc.The studies based on primary and secondary controlling factors indicate that the high-quality reservoir is the final products of five evolution stages in the geological history,which is mainly controlled by the meteoric palaeo-karstification during hypergene and by the bury dissolution during deep bury.The intensity of palaeo-karstification is controlled by the primary sedimentary microfacies and rock types,and the burial dissolution resulted in enlargement or shrinkage of the karst cavities.