The Feixianguan gas reservoirs in the Luojiazhai Gas Field， northeastern Sichuan Province， are composed of the porous oolitic dolomites The reservoirs mainly exist in the oolitic bank facies in the carbonate platforms， which were deposited in high energy environment and mainly controlled by tidal actionThe primary rocks were sparry oolitic limestone and micrite oolitic limestone， but dolomitization destroyed the original sedimentary textures The diageneses which are constructive to the reservoirs are mainly dolomitization and burial dissolutionThe dolomitization is the base of forming high quality reservoirsBurial dissolution mainly developed inside the primary micropores，  the partly filled intergranular porosities and the intercrystal porosities,which furthermore formed lots of enlarged pores，intergranular pores，oolimoldsThe diageneses which are destructive to the reservoirs are mainly the filling of minerals in secondary pores，the fissures and the dissolved cavernsThe data of fluid inclusion analysis showed that the filling of minerals mainly happened during the burial period