CO2-induced asphaltene deposition and wettability alteration on a pore interior surface

Interfacial and Confinement-Mediated Organization of Gas Hydrates, Water, Organic Fluids, and Nanoparticles for the Utilization of Subsurface Energy and Geological Resources

“…For example, asphaltenes dissolved in heptane tend to adsorb rapidly on the silica surface and form long fractals, while asphaltenes dissolved in toluene form larger aggregates that mostly remain in the pore center (the bulk solvent). Further, CO 2 has been shown to facilitate asphaltene destabilization and deposition that consequently alter the wettability of the interior pore surface …”

“…Further, CO 2 has been shown to facilitate asphaltene destabilization and deposition that consequently alter the wettability of the interior pore surface. 44 The hypothesis that certain types of nanoparticles can inhibit the aggregation, adsorption, and deposition of asphaltenes has been investigated. The higher adsorption affinity of asphaltenes for the surfaces of nanoparticles is expected to disrupt asphaltene aggregation in fluidic environments.…”

“…Calibrated insights into the fate of fluids in subsurface porous environments are needed. In this context, assessing the influence of pore sizes, shapes, geometries, surface chemistry on the structures, − dynamics, − ,− phase transitions, − rheology, − assembly, ,− and flow of confined fluids , is essential. Among these properties, there have been limited efforts to link the structures of confined fluids or assembly of molecules to the observed properties and the efficacy of fluid storage and recovery activities.…”

“…With rising interest in storing CO 2 in depleted hydrocarbon reservoirs rich in heavy hydrocarbons, the influence of multiphase fluids in confinement on asphaltene assembly and resulting effects on porosity require further investigation. The thermodynamics and kinetics of asphaltene assembly in confinement differ from that of bulk fluids due to the effects of pore size and surface chemistry. ,,, The self-assembly of asphaltenes is influenced by asphaltene concentrations and solvent compositions, − the presence of injection agents such as water, air, and CO 2 , ,, and temperature and mechanical conditions. , Smaller asphaltene aggregates are observed in confinement compared to in bulk solvents due to adsorption on the interior surface of the confining pores . Further, pores with diameters larger than 5 nm showed higher adsorption capacity for asphaltenes. , Clays such as montmorillonite and kaolinite adsorb asphaltenes preferentially to other surfaces, making pores of mineral clays more prone to pore blockage due to the adsorption of asphaltene molecules. , The dissociation of aggregated asphaltenes is effective in the presence of silica and alumina nanoparticles due to the high adsorption capacity of asphaltenes on the nanoparticles’ surface. − However, the adsorption of asphaltenes on the surfaces of the nanoparticles changes their properties and performance in inhibiting asphaltene assembly.…”

“…The thermodynamics and kinetics of asphaltene assembly in confinement differ from that of bulk fluids due to the effects of pore size and surface chemistry. 34,35,44,111 The self-assembly of asphaltenes is influenced by asphaltene concentrations and solvent compositions, 112−114 the presence of injection agents such as water, air, and CO 2 , 108,115,116 and temperature and mechanical conditions. 117,118 Smaller asphaltene aggregates are observed in confinement compared to in bulk solvents due to adsorption on the interior surface of the confining pores.…”