Changes in the Thermogravimetry and Kinetics Parameters of the Oxidation of the Resins and Asphaltenes in Heavy Crude Oil from Permian Deposits in Hydrothermal-Catalytic Processes

Thermogravimetric analysis (TGA) and differential thermogravimetry (DTG) at varying heating rates revealed distinct kinetic trends for the high-molecular-weight components of a heavy crude oil. The oil was extracted from a Permian reservoir rock sample from the Ashalchinskoye field, and the trends were characterized for both low-temperature (200–350°C) and high–temperature (350–600°C) oxidation regions. The oxidation patterns of a heavy crude oil and its resin–asphaltene components were compared, for the first time, after hydrothermal pretreatment of the rock at 300°C in a carbon dioxide atmosphere in the presence of a composite catalyst based on transition metals. The effects of adding the catalyst to the heavy-crude-oil-containing reaction system on the physicochemical properties of the heavy oil and on the oxidation rate of its components were identified. For resins, the thermo-oxidative effect was pronounced most strongly in the low-temperature oxidation range, whereas for asphaltenes the most significant alterations and mass losses were observed in the high-temperature oxidation region. Based on the kinetics obtained, the activation energies were calculated both for the hydrothermal and catalytic treatment.