<p>The aim of the research was to study the features of distribution of impurity metals in the distillates of several types of heavy oil produced in Uzbekistan, mixed with gas condensate. It has been revealed that the basic mass of impurities in the original oil is represented mainly by calcium salts of petroleum acids. Thermal decomposition of impurity metal naphthenates is accompanied by formation of highly corrosive organic acids. The concentration of organometallic compounds V, Ni, Fe and other d-elements in the oils produced in Uzbekistan is comparatively less than of the heavy oils in the known deposits of the Middle East and Russia. However, the corrosion activity of petroleum acids, together with the presence of hydrogen sulfide in the reaction medium, causes a sharp increase in impurities in the feedstock supplied to hydrotreating, in the form of a mixture of FeO (OH), FeO, Fe2O3, Fe0, Fe1-xS, FeS and CaS. It has been proven that for producing of environmentally friendly commercial fuels and oils, as well as ensuring long-term operation of catalysts for hydrotreating distillate and residual fractions obtained by processing local hydrocarbon raw materials, it is recommendable to use special protective layers that actively extract corrosion products, along with compounds such as naphthenates of calcium, nickel and iron.</p>