Experiments on artificial maturation of carbonaceous rock of the Domanik age in an autoclave in the presence of water at temperatures of 250, 275, 300 and 325A degrees C have been performed. It has been shown that a significant amount of soluble organic matter (OM) is produced from insoluble OM under these conditions. Changes have been observed in both the biomarker composition of the bitumen and the Rock-Eval OM maturity parameters characteristic of natural catagenesis. By the solid-state C-13 NMR technique, it has been shown that the amount of aliphatic units decreases and that of aromatic units increases in residual kerogen. Study the product composition of the pyrolysis of residual kerogen has revealed that the relative amount of precursors of n-alkyl structures increases as compared with low-molecular-weight aromatic and thiophenic structures.