RESERVOIR CHARACTERISTICS OF THE JURASSIC DOLOMITE IN THE QIANGTANG BASIN

The Jurassic dolomite is widely distributed in the Qiangtang Basin.It can be divided into dolomicrite,residual-grain dolomite and crystal grain dolomite three rock types.The former two are often adjacent or asso-ciated to gypsum,and the latter one has nothing to do with gypsum.In the postsedimentary changs,many kinds of diagenetic reconstruction have taken place,Among them,those which have some influences on the accumulation features of dolomite mainly include dissolution,recrystallization and tectonic stress processes.The major accumulation spaces of dolomite in the study area are intercrystal pores,intercrystal solution openings and tectonic fissures.Fine-coarse crystallized dolomite has good accumulation petrophysical properties,and is a kind of good-well reservoir.