Diagenesis of Reef-bank Reservoirs and Pore Evolution of Changxing Formation in Jiannan Area

On the basis of core observation and in combination with the data of thin sections and SEM(scanning electron microscope),the diagenesis,diagenetic series and pore evolution of Changxing Formation in Jiannan Area were studied attentively.The study result indicated that the diagenesis of Changxing Formation included cementation,compactionpressolution,re-crystals,dolomitization,dissolution and fracturing,in which the cementation,compaction-pressolution, re-crystals were the main destructive diageneses and the cementation was the main destruction of primary pores and majority of secondary pores.The dolomitization,dissolution and fracturing were the constructive diageneses,in which dissolution and fracturing were the main oil-gas reservoir space and migration passage of secondary pores and fractures.Diagenesis is one of the main control factors of reef-bank reservoirs,it controls the whole pore evolution.