Entrapment of Asphaltene-Stabilized Emulsions in Microfluidic Porous Media

Asphaltene-related flow assurance problems are prevalent in oil and gas production, with issues related to plugging of pipelines, damage to rock formations, and formation of viscous emulsions. In this study, entrapment of asphaltene-stabilized water/brine-in-oil emulsions in microfluidic porous media is characterized by two mechanisms: adhesion and hydrodynamic bridging. At lower water fractions, the droplets adhere to deposited asphaltenes, whereas erosion and bridging between posts are more prevalent at higher water fractions. Pressure drop measurements are used to calculate permeability reduction. With added salinity, weaker adhesion between droplets and deposited asphaltenes is observed; however, the increased droplet size leads to increased bridging. Interfacial rheology measurements are made to examine the stability of the interface. Higher salinity lowers the elasticity of the interface, resulting in larger emulsions, which exhibit more substantial erosion but increased bridging. The insights from this study can lead to better methods to demulsify and separate entrained water in produced crude oils, which can cause severe corrosion and fouling issues.