Abstract: In view of the lack of reservoir physical properties and the influence of barriers and interlayers on low oil saturation in the previous studies of the genesis of the Badaowan Formation reservoir in the Mosuowan Bulge, Junggar Basin, the analysis of reservoir low-saturation genesis was carried out from the aspects of pore structure, reservoir physical properties and heterogeneous barriers and interlayers, and the influences of structural amplitude on oil-water variation, reservoir physical properties on thickness of oil-water co-producing area, and barriers and interlayer on oil saturation were analyzed. The result shows: (1) The lack of obvious oil-water variation and incomplete oil-water replacement in the reservoir due to poor pore structure are the main reasons for the low oil saturation of the Badaowan Formation reservoir; (2) The relatively large oil-water co-production thickness caused by the physical properties of low porosity and permeability of the reservoir is the secondary reason for the low oil saturation of the Badaowan Formation reservoir; (3) Since the Badaowan Formation does not form regional and continuous barriers and interlayers, the barriers and interlayers have little effect on the low oil saturation of the Badaowan Formation reservoir. The research results will provide a basis for the efficient development of the Badaowan Formation and accelerate the exploration and development process.

Key words: poor pore structure, low saturation reservoir, Badaowan Formation, Junggar Basin