Abstract: On the basis of the sedimentary microfacies and the analysis of reservoir physical properties，a series of parameters
such as the porosity，permeability，flow zone index，etc，were selected for the classification of the flow units of oil formation
of Bi-301 wellblock H3 Member in the Zhaowa Oilfield of Biyang Depression were classified. According to the value of flow
zone index，the studying area has been divided into five flow units，named FU-A，FU-B，FU-C，FU-D and FU-E. The result
shows that all kinds of flow units have good corresponding relation with physical property，lithology，sedimentary microfacies.
Besides，the productivity of different flow units is analyzed. The results mainly indicate three respects. First，flow units’ classification
objectively reflects the geological characteristics of poor reservoir property and strong heterogeneity. Second，there
exists very significant power correlation between the single well productivity and flow zone index. Finally，the productivity
differences of different flow units are obvious，and FU-A with the best physical properties has the highest productivity while E
flow unit with the worst physical properties has the minimum productivity.

Key words: flow units, flow zone index, productivity analysis, Bi-301 Wellblock, Biyang Depression