Effective development of unconventional sources of heavy hydrocarbon raw materials is one of the main solutions to the global problem in the field of replenishment of the hydrocarbon resource base necessary to ensure the growth of the fuel and energy complex of the Russian Federation for a long period. The main methods of their extraction from the earth's interior are associated with thermal production methods involving heating productive oil-saturated formations to high temperatures causing low-temperature cracking of the underlying hydrocarbons. The paper presents the results of experimental studies simulating low-temperature cracking of heavy oil on the developed surface of mineral rock-forming compounds at a temperature of 360 °C and a pressure of 2 MPa. As a result of low-temperature cracking on the surface of carbonates Ca and Mg, the value of the aromaticity index of oil increases, the H/C ratio decreases, while the elemental and phase composition of mineral particles does not change. The proportion of low-molecular compounds formed as a result of cracking of resinous-asphaltene components of heavy oil increases in the composition of light hydrocarbons. Cracking is accompanied by the processes of denitrogenation and desulfurization of heavy oil, reducing the viscosity of oil. Benzene and alcohol-benzene resinous compounds of heavy oil in the cracking process are converted into lighter hydrocarbons. The presence of kaolin in the reaction medium leads to the formation of new light fractions of hydrocarbons boiling up to 200 °C. Economic indicators of upgrading heavy oils in the process of low-temperature cracking indicate an increase in net profit when selling products, which is associated with an improvement in the quality indicators of the upgraded oil. The results obtained will allow solving fundamentally new urgent problems associated with the development of effective technologies for the extraction of heavy hydrocarbon raw materials based on hydrothermal processes.