Microfluidic Study of the Deposition Dynamics of Asphaltene Subfractions Enriched with Island and Archipelago Motifs

Asphaltene-related flow assurance problems are prevalent in oil production processes and are at the heart of issues such as the plugging of pipelines, the damage of rock formations, and the stabilization of viscous water-in-oil emulsions. A comprehensive understanding of the interfacial behavior of asphaltenes, from a physical-chemical perspective, is required for an accurate design of solutions to these challenges. In this work, we elucidate the deposition dynamics of various asphaltene subfractions in a porous media microfluidic model. Extrography fractions from the interlaboratory sample known as PetroPhase 2017 asphaltenes, reported to be a mixture of abundant island and archipelago motifs, and Wyoming deposit C-7 asphaltenes, known for being island type dominated, are investigated. The deposition rate increases when the compositional ratio archipelago/island motif increases for PetroPhase 2017 derived fractions, whereas Wyoming deposit asphaltenes appear to exhibit stronger aggregation for fractions whose composition is uniformly island type. In general, the deposition rate is consistent with the amount of precipitated asphaltenes. However, the correlation is not merely a linear one and the pore-scale morphology changes even with similar deposition rates. Estimated diffusivity, the relative ratio of convection and diffusion, and fluid flow profiles are used to explain the dynamic growth of the deposit at the pore scale.