Rock cores testing indicate that space of carbonate rock reservoirs in Tahe oilfield are mainly interparticle pores

fissures and cavities; Their matrix almost do not have reserving capability. Reservoirs in cavity type

weathering fissure type and structural fissure type are commonly developed in Tahe region. Fissures in the surface eluvial belts-cavity reservoirs are largely spread near the unconformable contacts of C

1

and O

1

. Reservoirs in dissolution porosity- type in particle limestone in the platform edge of bank facies are commonly spread along the area of the lower Ordovician in Southern Sha well No.76.It is conjectured by analyzing relations between extension of the fissure series and the diagenetic fabrics that the cam shaft part in Akekuler would be favorable well-developed area for reservoirs in cavity type. New results from well drilling indicate that the area along well S

69

-S

76

in southern margin of Tahe oilfield will be a very important one for the exploration of reservoirs in dissolution porosity-type in particle limestone in the platform edge of bank facies.