Role of Water on the Precipitation and Deposition of Asphaltenes in Packed-Bed Microreactors

Abstract

Water naturally comprises some fraction of virtually all petroleum reservoirs worldwide, yet its existence introduces complexity to asphaltene precipitation and deposition mechanisms. This global problem not only impacts upstream conventional and unconventional energy production but also influences downstream chemical refining, the construction industry, and the transportation sector. A transparent packed-bed microreactor (μPBR) with inline analytics was designed to merge two fields of science, oilfield chemistry and microchemical systems, to investigate the role of water on the molecular-to-the-microscale deposition of asphaltenes in quartz porous media. Porosity loss and permeability impairment of the porous media for water mass fractions of <0.001 to 34.5 wt % were investigated. Interestingly, a switch in the mechanism of water (from 0.030 to 3.18 wt %) on the accumulation was discovered. Analyses of porosity–permeability relationships revealed competition between adsorption and desorption followed by pore throat plugging via mechanical entrapment for all mass fractions of water studied. Soluble water molecules were also found to decrease the asphaltene nanoparticle collision efficiency within quartz porous media where trace amounts existed (i.e., in the range of <0.001 to 0.030 wt % water), whereas higher mass fractions (>0.030 wt %) created the possibility of emulsion water blocking with more particles (relatively speaking) depositing on pore throat surfaces, precipitating by heterogeneous nucleation at asphaltene–water interfaces and/or experiencing catalyzed nanoaggregation at interfaces. In general, the water fraction was found to control the number of closed pore throats that interconnect the quartz porous media. Transparent packed-bed microreactors that bridge molecular-to-microscale understanding of asphaltene–water interactions are promising as tools for the advancement of asphaltene science and risk management during hydrocarbon production.