Some studies discuss the possibility of the abiogenic formation of naturally occurring hydrocarbons through their synthesis from a CO, CO2, and H-2 gas mixture. In this paper, based on the composition of fluid systems necessarily containing CH4 and S, another possibility of the abiogenic origin of natural hydrocarbon systems is considered. It is assumed that the interaction of endogenic CH4 and S is the initial stage of condensation processes occurring during the movement of fluid streams from the Earth's interior to the surface. Thus, sulfur present in petroleum turns out to be a system-forming function rather than a satellite component.