兩黏度不同的不互溶流體在多孔介質中，若以低黏度流體驅替較高黏度流體，由於兩流體之間的黏度差異、表面張力與濕潤性等影響下，導致流動介面不穩定，這種現象稱之為指形流。根據前人研究，在Hele-Shaw cell中以低毛細數下進行時變流率吸出能具有抑制的效果，本文確認這一方法是否同樣有助於提升具亂數分布顆粒的徑向多孔介質之驅替效果。研究結果顯示Hele-Shaw cell中，低毛細數下，時變流率能有效抑制指形的產生，其中排移流動的驅替效果優於浸潤流動。多孔介質中受到孔隙間毛細壓力之影響，排移流動傾向流往孔隙較大處，浸潤流動傾向流往孔隙較小處，且只有浸潤流動在低流率下才有些許的抑制效果，但兩者皆受到孔隙之影響使線性流率無明顯抑制效果。;When low-viscosity fluids displace higher-viscosity fluids, it causes the flow instability of the two-phase interface. This phenomenon is called viscous finger. According to previous studies, time-dependent suction flow rate can inhibit the viscous finger at a low capillary number in the Hele-Shaw cell. This study was to confirm whether this method is equally applicable to porous media. We perform the simulation of radial Hele-Shaw cell to analyze the influence of wettability. The results regarding the Hele-Shaw cell show the linear suction flow rate can indeed suppress finger at low capillary number, and drainage flow performs better than imbibition flow at maintaining the stability of the interface. Regarding porous media flow, little it can suppress finger that we use the linear suction flow rate. Under the influence of capillary pressure for differences pore sizes, drainage flow tends to flow to the larger pores and the imbibition flow tends to flow to the smaller pores. Because the wetting fluid can surround the particles by wetting the particles, imbibition flow has a larger fingering width, and display better displacement rates than drainage flow.
