Break | AIChE

Break

Asphaltene-related flow assurance problems are prevalent in the oil production process, and are at the heart of issues such as the plugging of pipelines, the damage of rock formations, and the formation of viscous emulsions. Understanding of the interfacial behavior of asphaltenes is required to design the effective solutions to these problems. In this study, we elucidate the deposition behavior of asphaltene-stabilized water/brine-in-oil emulsions in microfluidics and further use the double-wall ring (DWR) rheometer to characterize the rheological responses of the asphaltene interface. Firstly, various oil-to-water ratios (water concentration: 0.03 wt% to 20 wt%) are studied; we find that lower ratios give rise to higher permeability reduction, and that the deposition mechanism changes from adhesion to bridging. Moreover, less deposition is found with more salts in the adhesion-dominated stage, while more severe pressure drops are observed in the bridging-dominated stage, which is caused by larger emulsions in the presence of salts. Also, interfacial rheological elasticity of the interface reduces, and the disjoining pressure decreases with higher salinity. This combining effect results in larger emulsions. This alteration causes stronger erosion in the adhesion stage and facilitates blockage in the bridging stage. The zeta potential can be neutralized by salts, suggesting the possible screening effect of charged asphaltenes at the interface on the electrostatic attraction, and the inter-droplet disjoining pressure.