Abstract: This paper mainly describes the 3 principal factors for controlling physical properties of sandstone reservoirs in I-Ie formation 3，Shuanghe area，Henan. The factors are sedimenta-tion,postsedimental process(or diagenesis)and tectonism. The paper also points out that both porosity and permeability are closely related to the granularity midvaluc and the con-
tents of matrix. It is cementation and resolution that are key links for the contents of sec-ondary porosity. For this fan delta-sublake fan system，the favorable oil and bas一bearing region is the mid fan ,and the outer fan is a spectacular place on secondary exploration for oil and bas.

Key words: Reservoir Physical property Granularity midvalue M