Genesis of Deep Abiogenic Hydrocarbon Systems

Deep hydrocarbon systems form through transformation of high-temperature deep fluids, which comprise mixtures of various volatile compounds. These processes determine the elemental and group composition of crude oil and natural gas. According to available data, deep fluids represent mixtures of methane, hydrogen, water, carbon dioxide, carbon, hydrogen sulfide, elemental sulfur, NO2, and metal-containing structures. Methane, the main component of deep fluids, is generated in large quantities in the Earth’s interior. Since some components of these mixtures exhibit catalytic activity in the processes of hydrocarbon polymerization, it can be assumed that deep fluids constitute a natural catalytic system. Elemental sulfur present in deep fluids possesses catalytic properties, thus being capable of triggering polymerization processes. This leads to the formation of high-molecular hydrocarbon and organosulfur structures. Metals in deep fluids, particularly vanadium as a catalyst, also trigger the formation of high-molecular complexes, such as porphyrins. Due to incorporation of sulfur and vanadium into crude oils, they become the largest concentrators of these elements. The variability of the ratio of these elements in deep fluids and their redox character affects the intensity of hydrocarbon polymerization processes and formation of organosulfur compounds and metal complexes. This leads to generation of either crude oils with various sulfur and metal contents or natural gas systems.