The results of thermolysis of vacuum resid of West Siberian oil are reported. A mathematical model has been built and kinematic relationships of the process of production of an oil-caking additive, namely the thermolysis residue, have been described. It is shown that conversion of the feedstock into volatile products occurs via the quasi-linear mechanism of first-order reactions, whereas conversion into carbenes and carboids (D +/--fraction) occurs via the autocatalytic mechanism of self-accelerating radical processes. In order to support the theory of autocatalytic mechanism, the effect of addition of various quantities of carbine and carboid concentrate to the feedstock composites on the polycondensation reaction rate was studied. It was observed that the group composition of the thermolysis residue changes nonadditively, which attests to autocatalytic action of carbines and carboids added to the thermolysis feedstock.