Abstract: Regarding the uncertainties in understanding the relationship between sedimentary microfacies types and their physical properties of dolomite reservoirs in the Sinian Dengying Formation, Penglai gas area, Sichuan Basin, the study aims to accurately describe the pore structure characteristics of these reservoirs and their correlation with sedimentary microfacies. The carbonate reservoirs in the second member of the Sinian Dengying Formation in the Penglai gas area of the Central Sichuan Paleouplift were selected as the research object. Based on drilling core data, with comprehensive analyses of thin sections, cast thin sections, and imaging logging data, the sedimentary microfacies types in the study area were systematically classified. High-resolution rotating-drum core scanning technology was applied to classify and quantitatively analyze the pores, caves, and fractures throughout the entire core section. Six sedimentary microfacies were mainly developed in the second member of the Sinian Dengying Formation in the Penglai gas area, including mound core, mound flank, mound flat, mound base, mound cap, and still-water dolomite mud. Different sedimentary microfacies exhibited distinct lithological assemblages and imaging logging characteristics. The reservoir space in the study area was classified into seven types based on size and fluid migration capacity: intercrystalline pores, intercrystalline dissolved pores, small-scale pore-type caves, medium-scale pore-type caves, large-scale fracture-type caves, structural fractures, and dissolution fractures. Intercrystalline pores and intercrystalline dissolved pores were dominant in number but accounted for a smaller area, while small-, medium-, and large-scale caves contributed more significantly to reservoir space. Sedimentary microfacies exerted a significant influence on reservoir development. Based on the development degree of pores, caves, and fractures and their correlation with fracture development scale, the reservoirs in the study area could be classified into three types: high porosity and high permeability reservoirs represented by mound cores and mound flanks; high porosity and low permeability reservoirs represented by mound flats and still-water dolomite mud; and low porosity and low permeability reservoirs represented by mound bases and mound caps.