| Imbibition is of particular importance to oil recovery from fractured reservoirs. There are many researchers focusing on simulating imbibition process by using various kinds of equipment, such as capillary tubes with simple circular cross-section or a more complex one with corners, as well as real core samples. Significant results have been obtained on the characteristics of imbibition process, such as the factors influencing imbibition, phenomena happening in imbibition process and geometry of channel, which can influence oil recovery. In this thesis, the attention focused on microfluidic fabrication techniques to simulate imbibition process. In the process of imbibition, snap-off is one important phenomenon, due to its great influence on oil recovery. Hence, parameters affecting snap-off to happen have attracted interest. The essence of snap-off refers to droplet formation of one fluid in another immiscible fluid, therefore, the research on factors influencing droplet formation is the meaningful way to set foundation for further study of snap-off. The microfluidic fabrication method has been taken to simulate co-current imbibition process and observe the phenomena during this series of experiment. Geometry of nozzle, flow rate ratio and viscosity are the main factors studied in snap-off formation process. The variation of these factors lead to the change of drop size, arrangement mode and formation frequency. |
