Xin Yang ^1* Bo Kang ¹ Bin Xu ¹ Hehua Wang ¹ Chunxiang Zhou ¹ Kai Jiang ¹ Xingfu Li ²

• ¹ Chengdu North Petroleum Exploration and Development Technology Company Limited, Chengdu, China
• ² State Key Laboratory of Oil and Gas Reservoir Geology and Development Engineering, Southwest Petroleum University, Chengdu, Sichuan Province, China

Permeability is a fundamental property of porous media that describes the ability of a pore network to allow fluid flow through its pore spaces. However, permeability values can vary based on the fluid used in testing. To examine the influence of various fluids on permeability, without accounting for fluid-solid interactions, we measured 30 clay-free Fontainebleau sandstones and 30 clay-free Y sandstones using kerosene and N2. Our experiments revealed that all samples consistently exhibited lower oil permeability compared to the Klinkenberg-corrected gas permeability. Furthermore, SEM analysis revealed that the presence of liquid films on rock surfaces and particle migration within pore throats contribute to the permeability disparity between liquid and gas in Fontainebleau sandstone. For Y sandstone, its lesser hydrophilicity compared to Fontainebleau leads to a negligible presence of liquid film. The primary reason for the reduced liquid permeability, in comparison to gas, is particle migration. We also explored the relationship between the slip factor and permeability. We observed a more pronounced slip effect in Y sandstone than in Fontainebleau, attributed to its finer pore throats.