Abstract: A flow unit is defined as a volume of reservoir rocks that is extensive both vertically and laterally,and has similar lithology and physical property that affect fluid flows.The flow units are based on the numerical modelling of petroleum deposits,and has important implications for the development of oil and gas fields,especially for the secondary or tertiary recovery.The current research focus both at home and abroad is directed more to the classification schemes of flow units.This paper aims to provide a useful tool by which the storage coefficients and seepage coefficients can be calculated in terms of the data on porosity and permeability.As a result,the flow units can be identified by means of cluster analysis of the storage coefficients and seepage coefficients obtained.This method is convinent and conductive to the analysis of a single sedimentary microfacies.