Abstract: To address the problem of unclear understanding of the pore structure of low-permeability reservoirs in Quantou Formation, Wangfu Fault Depression, Songliao Basin, the fractal method of reservoir pores was applied in combination with experimental methods such as X-ray diffraction, casting slice, scanning electron microscopy, and mercury intrusion porosimetry, to determine the pore fractal characteristics of the low-permeability sandstone reservoir and discuss the relationship between the fractal dimension and the physical properties and mineral composition of the reservoir. The experimental results showed that: the pores of the reservoir in this area were mainly intergranular pores and intragranular dissolved pores; the mineral components were mainly quartz and feldspar; the pores of the reservoir were of multiple fractal characteristics, and the structure of small pores was better than that of medium and large pores; the fractal dimension was unrelated to the reservoir porosity, but closely correlated with permeability and mineral composition. This study discovers the pore size distribution characteristics of low-permeability reservoirs from the perspective of multiple fractal theory, and provides a basis for the development of low-permeability reservoirs in Quantou Formation, Wangfu Fault Depression, Songliao Basin.

Key words: low-permeability reservoir, pore structure, mineral composition, mercury intrusion porosimetry test, fractal dimension