Abstract: Macroscopic reservoir properties of fluvial reservoir bodies and single sand bodies in the Guantao Formation in Gudao oilfield are determined through fine reservoir sedimentology study under small spacing well pattern conditions.The fluvial sand bodies are classified into4microfacies sand body units including main stem,crevasse channel,filling channel and peripheral channel with silt-stone and fine sandstone facies as the main lithofacies and with low degree of consolidation.Single stage fluvial sand bodies have the characteristics of meander rivers,there exists a linear correlation between the width andthickness of rivers and that of single stage fluvial sand bodies,and the inner structures of sand bodies accord with the accumulation pattern of point bars.Different micro-facies units of fluvial sand bodies control the overall reservoir physical properties at high water cut stage.