Effect of Dynamic Contact Angle on Spontaneous Capillary-Liquid-Liquid Imbibition by Molecular Kinetic Theory

Abstract

Summary Imbibition is one of the most common physical phenomena in nature, and it plays an important role in enhanced oil recovery, hydrology, and environmental engineering. The imbibition in a capillary is one of the fluid transports in porous media, and the effect of a dynamic contact angle that changes with the imbibition rate on liquid-liquid imbibition is not clear. In this paper, the molecular kinetic theory (MKT) is used to study the effect of a dynamic contact angle on spontaneous capillary-liquid-liquid imbibition at a micrometer scale. The results show that: Using a scaling time, the effects of various forces in different imbibition systems can be compared, the influence of a dynamic contact angle on imbibition can be characterized by a frictional effect of the three-phase contact line, and the proposed model considering the effect of a dynamic contact angle is better than the model neglecting the effect of a dynamic contact angle. As the displacing phase viscosity increases, the influence of a dynamic contact angle on imbibition strengthens, which is attributed to a decrease in the viscous effect and an increase in the frictional effect during the imbibition process; as the displaced phase viscosity increases, the influence of a dynamic contact angle on imbibition weakens, which is attributed to an increase in the viscous effect and a decrease in the frictional effect during the imbibition process. As the interfacial tension increases, the frictional effect increases, with the result that the effect of a dynamic contact angle on imbibition increases. As the capillary becomes more hydrophilic, the effect of a dynamic contact angle on imbibition becomes stronger because of a decreasing viscous effect and an increasing frictional effect. As the capillary length increases, the viscous effect increases, whereas the frictional effect decreases, leading to a decrease in the dynamic contact angle effect. As the capillary radius increases, the frictional force decreases, whereas its proportion in total resistance or the frictional effect increases, resulting in an increase in the effect of a dynamic contact angle. This work sheds light on the effect of a dynamic contact angle on capillary-liquid-liquid imbibition, including displacing phase viscosity, displaced phase viscosity, interfacial tension, capillary wettability, length, and radius. It will provide new insights into manipulating a capillary imbibition process and provide a fundamental theory for enhanced oil recovery by imbibition in conventional or unconventional reservoirs. Supplementary materials are available in support of this paper and have been published online under Supplementary Data at https://doi.org/10.2118/205490-PA. SPE is not responsible for the content or functionality of supplementary materials supplied by the authors.

Coupling the Dynamic Contact Angle into the Dynamic Imbibition Model for Fractal Porous Media

“…One may expect that increasing the contact angle decreases the hydrophilicity of the capillary and thus reduces the effects of friction in the capillary. 32 The results highlight that considering the DCA is important for the DI process in tight rocks which are relatively more water-wet. imbibition rate and recovery by increasing IFT.…”

“…Experimental studies have examined the dynamics of the contact angle with time in a capillary, and demonstrated that the contact angle changes with flow velocity. , Models have been developed to describe the dynamic contact angle (DCA) in a capillary. − Studies have modified the Washburn equation to consider the DCA for the process of capillary rise in tubes . Recently, several studies have coupled the DCA into SI models for porous media. − Additionally, the DCA has been considered for the SI model in fractal porous media . However, limited research has been reported to model the DI process by considering the effects of the DCA for tight reservoirs.…”

Mathematical Model and Application of Spontaneous and Forced Imbibition in Shale Porous Media-Considered Forced Pressure and Osmosis

“…Many empirical models of dynamic contact angles are established. Tian et al believed that the cosine of the dynamic contact angle has a linear relationship with the percolation rate. where θ e (°) is the equilibrium contact angle, ζ (Pa·s) is the frictional coefficient of a three-phase contact line, γ (N/m) is the surface tension, and v c (m/s) is the solid–liquid–liquid contact-line velocity. At the beginning of the flow, the dynamic contact angle begins to change.…”

“…Many empirical models of dynamic contact angles are established. Tian et al 26 believed that the cosine of the dynamic contact angle has a linear relationship with the percolation rate.…”

Abnormal Phenomena and Mathematical Model of Fluid Imbibition in a Capillary Tube

“…Soares et al (2005) [16] found that an uncertainty of contact angle in imbibition studies since the displaced liquid can stick to the capillary-tube wall and consequently influences contact angle during this imbibition process. The uncertainty of contact angle on process of imbibition is also related to interfacial tension [17,18]. Thus, the contact angle (which is influenced by the above factors) is likely to affect imbibition rate, but it does not affect the law of imbibition rate with time.…”