Experimental study of oil–water two-phase flow in a capillary model

The flow and mobilization of an oil slug surrounded by water in a unique capillary tube model is experimentally investigated in this research. A single oil slug with different lengths is mobilized under stationary conditions. It is found in the investigation that the development of a water film between the tube wall and the oil slug is crucial for the flow and mobilization of the oil slug. Four different phenomena of the two-phase flow are discovered during the water film development, in corresponding to different rates of water injection velocity versus oil slug length, namely: water film developing forward, water film developing backward, water leakage, and oil slug breaking up. The effects of the flow parameters on the oil slug flow are studied in detail. The relationship between the two-phase flow and the correlating parameters such as injection rate and oil slug length is quantified, and the correlating parameters have evidently shown as the dominating factors to the characteristics of the two-phase flow.