A theoretical study of bubble entrapment in pore doublet models : dynamic contact angle and supplying principle

Abstract:

Pore doublet model, which is a simple network with two connected capillaries, has been widely used to study the residual phase saturations in porous media. In this study, we theoretically investigate the behavior of residual nonwetting saturations in two pore doublet models: Moore and Slobod Model and Wielhorski Model. Moore and Slobod Model consists of two uniform separated capillaries in parallel connection. Wielhorski Model consists of two parts: the first part continuously interconnected, and the second part connected only by nodes. The wetting fronts movement have been described based on Washburn equation, supplying principle, and modified Washburn equation which takes dynamic contact angle into account. In Moore and Slobod Model, the bubble can be only trapped in the microchannel, but, in Wielhorski Model, the distribution of entrapped bubbles (in microchannel or macrochannel) can be controlled by the injection pressure. The bubble volume rates change with not only the injection pressures but also different geometrical configurations (radii and lengths of the channels).