Abstract:

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.

Key words: Dengying Formation, dolomite, highquality reservoir, porosity evolution, dissolution