ゼロエミッション社会構築にむけたCCS/CCUS技術開発

[1K0101-10-03] 残留ガストラップ現象において粒子の形状が毛細管脱飽和曲線に及ぼす影響

○胡 映学¹、末包 哲也¹ (1. 東京工業大学)

司会：菅井裕一（九州大学）

キーワード：毛管トラップ、毛細管脱飽和曲線、粒子形状、残留飽和率、界面積

The trapping of gas by capillary forces in the pore space is an essential process to increase capacity and ensure the safety of carbon dioxide storage. The capillary desaturation curve describes the change in residual saturation as a function of capillary number. However, the impact of grain geometry on the capillary desaturation curve has not been conceived yet. In this work, the unconsolidated porous media with three kinds of shapes were selected. Glass beads, silica sands and plastic particles represent spherical, moderated and highly angular grains, respectively. High-resolution micro-tomography was used to obtain the morphological characterization of residual gas inside porous media. The results indicate that under low flow rate (capillary forces controlled regime), the residual gas saturation is independent of capillary number. Higher volume of gas bubbles were trapped in porous media with angular particles than spherical particles. In addition, the bubble size distribution and interfacial area were also sensitive to the particle shape. When the capillary number increases above a critical value, the residual saturation decreases sharply for all kinds of packings. The grain geometry has a weaker effect on the capillary trapping during dynamic flow regime