Study on Permian organic reef reservoir characteristics of north Sichuan

On the basis of data analysis of 110 rock samples,83 thin section samples and 22 core mercury injection of Permian Changxing Formation in North Sichuan area and through the analysis and research of reservoir lithology,reservoir physical properties,pore structure and reservoir con-trolling factors,we know that the lithology of Permian organic reef reservoirs is mainly bioclastic limestone,reef limestone and fine-powder dolomite.The reservoir storage space is mainly secondary intercrystal pore,intragranular dissolved pores,intergranular dissolved pores and fractures.The porosity of reservoirs is 2%-6%,and the permeability is mainly(0.02～0.25)×10-3μm2,which belong to middle-low permeability reservoirs.The reservoirs of the study areas mainly belong to type Ⅱ,type Ⅲ and type Ⅳ are the next.