Experiments were conducted simulating hydrothermal conversion of heavy oil in the presence of carbonate, kaolin, Al₂O₃, Ni²⁺ and Cu²⁺, NiO mixed with poly-α-olefins, C₆H₈O₇, C₂H₄O₂ at 290–375 °C and 10–135 bar. Al₂O₃, carbonate at 375 °C and 135 bar, accelerated the resin degradation. Experiments with carbonate at 350 °C and 10 bar showed no significant composition changes. NiSO₄, CuSO₄, kaolin mineral, at 350 °C and 78 bar, accelerated decomposition of resins (from 35.6% to 32.5%). Al₂O₃ and carbonate at 290 °C and 14 bar led to the destruction of asphaltenes (from 6.5% to 4.7% by weight), which were adsorbed on the surface of carbonate. Al₂O₃, NiO, poly-α-olefins at 350 °C and 78 bar accelerated C–C bond cracking of high-boiling asphaltenes. C₆H₈O₇, rock-forming carbonate, at 360 °C and 14 bar, contributed to the polymerization and polycondensation of hydrocarbons with the formation of additional resins. C₂H₄O₂ and kaolin at 360 °C and 12 bar affected the reduction in the resin content from 35.6% to 31.9% wt. C₂H₄O₂ interacted with the active metals with the formation of acetate salts exhibiting catalytic activity.

The results of experiments on the oxidation of viscous oil deposits by atmospheric oxygen in the presence of oxidation catalyst and at temperatures and pressures close to the reservoir conditions are presented. Decreasing of density and viscosity of converted oil, increasing of oil and asphaltene content and emergence of high-molecular n-alkanes are revealed.

The results of experiments on the transformation of heavy oil in a steam-laden environment, at temperatures and pressures ensuring the presence of water in a superheated steam state, as well as in the subcritical and supercritical states are presented. It is shown that supercritical water provides the largest formation of light fractions having a boiling point of 350 °C: their content has increased by 2.5 times. Subcritical water, in contrast to water in the supercritical state, ensures the formation of light fractions at 73% rel. and reduces the content of asphaltenes by 53% rel. compared with the initial oil.