Stability of liquid bridges with elastic interface

Abstract

Low salinity waterflooding (LSWF) has been proposed as way to increase oil recovery. Albeit various proposed mechanisms for LSWF improved oil recovery, no consensus exists currently. Alvarado et al. showed that a strong correlation between incremental oil recovery and high interfacial viscoelasticity exists. This interfacial response to LSWF has been proposed to hinder snap-off. Our work provides compelling evidence that snap-off suppression correlates with crude oil–water interfacial elasticity (IFE) and interfacial tension (IFT). The proposed mechanisms is tested using a novel fluid bridge setup. IFT and IFE were measured in deionized water containing either sodium chloride or/and sodium sulfate. Bridge experiments were conducted with the same oil-aqueous phase combinations as those used in IFT experiments. The bridge geometry was tracked while the oil was pumped out until bridge failure. The critical neck diameter (CND), corresponding to the minimum neck diameter before snap-off, represents our stability proxy. Results show that as the interfacial elasticity increases over time, the bridge becomes more resilient against deformation. This behavior is explained by adducing that a decreasing local interfacial area produces a larger IFT drop, if the IFE increases. The smaller IFT lowers the bridge fluid's pressure gradient, consequently decreasing the fluid pump-out action. This is the first time, to the best of our knowledge, that a fluid bridge has been used to evaluate the stability of an elastic interface. The technique has potential broader impacts, including the understanding of biological membranes and enhanced oil recovery, among others.