Water Alternating Alkane Injection: A Molecular Dynamics Simulation Study

Abstract

Abstract In a recent study, we observed that the diffusion coefficient of common hydrocarbons in crude oils are more affected by the presence of different hydrocarbon components than the effect of confinement. Based on our previous observations, in this study, we investigated the efficiency of smaller-chain alkane injection into oil-soaked sandstone pores to dilute the oil with alkane. We used molecular dynamics simulations of C2, C3, C4 and C5 as well as a mixture of C3 and C4 to rank the effects of different alkanes on the diffusion and distribution of oil molecules in pore. As water-alternating-alkane injection would bring water into the pores, our simulations included water. Our results indicate that alkane injection into sandstone reservoirs has a significant potential due to the fact that it effectively dilutes the oil. Water always wets quartz surface relative to the oils. Injection of water therefore should be effective in detaching oil molecules on the surface. Presence of water layers did not affect the diffusion coefficients of oil molecules.