Wettability alteration in subsurface environments is one of the key factors that influences our ability to recover or store fluids in subsurface environments in an environmentally sustainable manner. One of the critical factors that influences flow in subsurface environments is the closing of pore spaces also known as pore fouling. The self-assembly of polyaromatic macromolecules also known as asphaltenes in hydrocarbon-bearing reservoirs is one example of subsurface phenomenon leading to pore fouling. However, there is a limited understanding of how this phenomenon influences the wettability alteration of solid surfaces (e.g., calcite, silica and illite). In this study, we characterize the dynamic changes in the wettability alteration of solid surfaces (e.g., calcite, silica and illite) resulting from the self-assembly and adsorption of polyaromatic macromolecules known as asphaltenes in heptane and toluene solvents at 200 bar and 313 K using classical molecular dynamics simulations. The self-assembly of asphaltenes on the solid surfaces and accumulation on water/hydrocarbon interfaces increased the equilibrium contact angles on calcite, silica and illite surfaces from 25-34o to 69-79o, suggesting an enhancement in the hydrophobicity of solid surfaces. Asphaltene accumulation at the water/oil interfaces reduced the interfacial tension of water/heptane and water/toluene, and stabilized the water droplet. Dynamic wettability alteration contributed to changes in the organization of hydrocarbon fluids (e.g., heptane and toluene) near solid surfaces and reduced the self-diffusivities of these molecules.

Influence of self-assembly of polyaromatic macromolecules on the dynamic wettability alteration of calcite, silica, and illite surfaces

2019 Fall National Meeting

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