低炭素社会構築のためのCCS（3）

[1507-10-03] Three-dimensional visualizations of miscible viscous fingering with chemical reactions in porous media

○Sotheavuth Sin¹, Tetsuya Suekane¹ (1. Tokyo Institute of Technology )

司会:佐々木 久郎(九州大学)

Keywords:three-dimesional, miscible viscous fingering, viscosity increase, viscosity decrease, chemical reactions

Viscous fingering is a hydrodynamical flow instability occurring when a more-viscous fluid (MVF) is displaced by another less-viscous fluid (LVF) and take place in either miscible and immiscible systems. In this study, we investigate the three-dimensional characteristics of miscible viscous fingering with chemical reactions using a microfocus x-ray computed tomography (CT) scanner and we also visualize the two-dimensional images of the fingers to see how the concentration and the viscosity of the displacing fluid change along the finger with respected to the color calibration using image processing (ImageJ). With an increase in the Péclet number for the viscosity increase system, the length extension of the tip of the most-advancing finger remains unchanged in the reactive case, but it contrastingly decreases in the non-reactive case. For the viscosity decrease system of either the reactive case and the non-reactive case, however, the length extension of the tip of the most-advancing finger decreases with increasing the Péclet number. The maximum concentration of NaI in LVF inside the finger linearly decreases while it sharply decreases at the tips of the fingers. An increase in viscosity due to the chemical reactions causes the finger widening and the suppression of the shielding effect. A decrease in viscosity due to the chemical reactions, however, causes the finger narrowing and the enhancement of the shielding effect. As a result, the received sweep efficiency from the reactive case is larger than that in the non-reactive case for the viscosity increase system. In contrast, the received sweep efficiency from the reactive case is smaller than that in the non-reactive case for the viscosity decrease system.