Abstract: Subtle reservoir division is a hard problem,for the iden- tification on seismic and geological data is defective in resolu- tion.Through the study on physical property character and pore structure character of Z408 and Z411 sand bodies,the existence of' the two different sand bodies is proved.Then the provenance direction is analyzed in terms of discrepancy of physical properties.It is demonstrated that it is feasible to acquire the subtle reservoir division from the porosity mode.