Application of molecular dynamics simulation in CO2-EOR and CO2 geological storage: A review

Abstract

Carbon capture, utilization and storage (CCUS) technology is a strategic solution to the dual challenges of global energy demand growth and greenhouse gas emission reduction. The core components—CO₂ enhanced oil recovery technology (CO₂-EOR) and CO₂ geological storage technology, have become a research hotspot in the field of international energy. As a powerful tool, Molecular Dynamics (MD) simulation can be used to reveal the evolution law of crude oil occurrence state in nano-confined space, the multiphase interface behavior of CO₂-crude oil and the adsorption and storage characteristics of CO₂ on mineral surface. However, the real reservoir environment is very complex. How to accurately characterize the oil displacement process and storage effect of CO₂ by MD simulation has become a bottleneck problem to be solved. From the perspective of MD simulation, this paper reviews the latest research progress in three directions: the occurrence and migration mechanism of hydrocarbon fluids in nanopores; the mechanism of CO₂ on heavy components and miscible displacement; the influence mechanism of different geological storage sites on the long-term sequestration of CO₂. The problems and challenges in the current research are pointed out, and reasonable suggestions are given. Future MD simulation research should center on building more accurate molecular structure models, selecting more suitable molecular force fields and constructing multi-scale simulation methods. This review provides theoretical support for CO₂-EOR and optimization of CO₂ geological storage technology in unconventional reservoirs, which opens up a new path for the development of oilfields and the realization of carbon neutrality goals.