Study on the characteristics and mechanism of low-temperature oxidation of heavy oil using ReaxFF molecular dynamics simulation

Heavy oil is a crucial energy resource, and in-situ combustion (ISC) is regarded as one of the most efficient technologies for its recovery. Low temperature oxidation (LTO) is a critical process in enabling ISC technology. The Reactive Force Field (ReaxFF) method was employed to investigate the low-temperature oxidation (LTO) of heavy oil. The simulation results closely align with experimental data, validating the accuracy of the heavy oil model. The study reveals that LTO initiates with the decomposition of long carbon chains, resulting in the formation of alkylperoxy radicals, while CO₂ is produced from the oxidation of smaller carbon fragments. The residual products of LTO include polycyclic aromatic hydrocarbons and aromatic compounds. These molecular-level insights into the LTO mechanisms offer valuable guidance for optimizing the process of in-situ combustion (ISC).