Abstract
Heavy oil reserves constitute over 70% of global crude oil resources, yet their extraction remains challenging due to high viscosity and poor flowability. Multicomponent thermal fluid (MTF) technology, integrating CO(2), N(2), and steam, offers a promising solution by enhancing emulsification and mobility. This study employs molecular dynamics (MD) simulations to unravel the microscale emulsification mechanisms of heavy oil under MTF. By systematically varying gas-to-oil ratios (R), we identify favorable ratios of R = 1.3 for CO(2) and R = 0.85 for N(2), validated through analyses of diffusion coefficients and radial distribution function (RDF). The addition of MTF increased the diffusion coefficient of the oil droplets to 0.9565 × 10(-8) m(2)/s, which is 56.4% higher than the effect of the CO(2) system and 85.6% higher than the effect of the N(2) system. This improved transport behavior correlates with emulsion stabilization mechanisms evidenced by distinct RDF peaks at interfacial separation distances of 0.40 nm (Oil-CO(2)) and 0.51 nm (Oil-N(2)). The results demonstrated that the combination of CO(2), N(2), and H(2)O significantly facilitated the dispersion of oil droplets and enhanced emulsification. The findings will offer microlevel guidance and theoretical support for efficient heavy oil extraction.