On the Biogenic Pathway of Formation of Accumulations of Oil and Associated Gases from the Point of View of Isotopic Biogeochemistry

The only possible biogenic pathway for the formation of oil and associated gases is considered. In this case, the carbon source for transformations is the carbon from the biomass of "living organisms". The path consists of three segments: 1) Prebiogenic, which is controlled by gravity and synchronizes the movement of lithospheric plates and the synthesis of "living matter" on the next segment. 2) The biogenic segment, where the synthesis of "living matter" occurs by photo- and heterotrophic pathways. At the same time photosynthesis provides heterotrophic synthesis by substrates. 3) The post-precipitation segment involves the conversion of biogenic material into an insoluble three-dimensional organic polymer, called kerogen, and into labile organic compounds, mainly of a hydrocarbon nature, called bitumoids. Part of the latter, migrating and getting in a trap, forms an oil deposit. Associated gas is formed as a result of cracking of the terminal fragments of kerogen and bitumoid. The processes occurring in each segment are confirmed by experimental data on carbon isotopes, as well as reconstructions of the environmental and climatic phenomena based on geological and paleontological data.