南华北地区在早古生代沉积了巨厚的碳酸盐岩,为碳酸盐岩储层的形成提供了有利条件。通过对大量野外剖面、钻井岩心的详细观测和室内显微薄片分析,系统研究了该区下古生界碳酸盐岩的成岩作用类型和特征,主要成岩作用类型包括:①压实、压溶作用;②胶结作用;③重结晶作用;④白云石化作用;⑤交代作用;⑥溶蚀作用;⑦构造破裂作用等。对成岩作用阶段进行了划分,深入研究了不同成岩阶段成岩作用类型及特征。退后生期和进后生期溶蚀作用、构造破裂作用较强,对储层的形成有利,成岩期和后生期的白云石化作用也有利于孔隙的形成和保存。岩溶作用和白云石化作用对该区下古生界储层形成具有明显的控制作用,中奥陶统马家沟组主要为岩溶储层,上寒武统主要为次生白云岩储层,同时建立了该区下古生界岩溶作用模式和白云石化作用演化模式。
This paper mainly focuses on the lower Paleozoic carbonate diagenesis in southern North China,located in the north of Qinling-Dabie orogenic belt or the south of the North China block,across the stable North China block,the deformation belt of southern block margin and the north margin of Qinling-Dabie orogenic belt. Based on the study of field sections,drilling cores and microstructural slides,the paper discusses the types and characteristics of the Lower Paleozoic carbonate diagenesis,including compaction,fracturing and pressure-solution,cementation,recrystallization,dolomitization,karstification and metasomatism. Then,by dividing the diagenesis stages,it studies in detail the types and characteristics of each diagenesis stage. In addition,it describes the characteristics of karstification and dolomitization that control the formation of reservoirs,including the display of karstification,developing sections,so as to have established the model of karstification and different dolomitization.