A physical model has been developed for the aquathermolysis of heavy crude oil from the Ashalchinsk oil field at 250 degrees, 300 degrees, and 350 degrees C. Nickel and cobalt carboxylates were used as oil-soluble catalyst precursors. In the presence of a hydrogen proton donor at 300 degrees C, the oil content was found to rise considerably and the resin content was found to decrease by a factor of 1.8, which leads to a decrease in crude oil viscosity by 91% and a decrease in density from 960 to 933 kg/m(3). The hydrocarbon composition of the liquid aquathermolysis products was studied by chromate-mass spectrometry. The average molecular weight of the asphaltenes was determined by matrix-assisted laser desorption/ionization (MALDI) spectrometry. The maximum disproportionation of the hydrocarbons into n-alkanes, alkylcyclohexanes, and alkylbenzenes occurs at 300 degrees and 350 degrees C. The composition of the hydrogen proton donor (tetralin) conversion products at these aquathermolysis temperatures was determined.