著者

Tadashi YOKOYAMA Satoki SHINTAKU Naoki NISHIYAMA

出版者

Japan Association of Mineralogical Sciences

雑誌

Journal of Mineralogical and Petrological Sciences (ISSN:13456296)

巻号頁・発行日

pp.221107, (Released:2023-03-11)

被引用文献数

1

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Rocks have pores of various sizes. We investigated which pore sizes filled with water and in what order with the progression of water infiltration. The pore radii of the sandstone mainly ranges from a few µm to several tens of µm. Water was passed through the sandstone core at 25 °C, and water saturation, S, was adjusted to 63%, 67%, 71%, 87%, and 100%. At each S, the porewater radius distribution was measured using the water expulsion method, in which water in pores of a given pore radius was expelled by gas pressure. The results showed that the porewater radius distribution was approximately the same for S = 63-71%. As S increased from 71% to 100%, the pores with 4-10 µm and 10-20 µm radii were filled with water first, followed by pores with 20-52 µm radius. For S = 63-71%, water was considered to have entered via adsorption on the pore walls and capillary action at the corners of the pore. Because this water cannot be expelled by gas pressure, an increased amount of water was not detected by the water expulsion method. As for the results at S >71%, a theoretical model of the dissolution of entrapped air, assuming a cylindrical shape, showed that the length of the trapped air decreases faster in pores with small radii than in those with large radii. This may be a major explanation for the experimental result, which showed that pores with small radii fill with water more quickly than those with large radii.