We demonstrate that the conditions established in laboratory settings—such as initial reaction products, thermobaric parameters, and redox environments—are indeed analogous to those that may exist in the Earth's upper mantle. The experimental results confirmed that hydrocarbon fluids with diverse compositions can form within the upper mantle. This leads us to propose that these fluids, generated through mantle-magmatic processes, can migrate from sub-crustal zones along deep faults and fractures and be injected under high pressure into the rock, ultimately forming oil and gas deposits. As the ascending fluid cools and the partial pressure of hydrogen decreases, it transforms into liquid oil and subsequently into polymeric insoluble carbonaceous matter (kerogen) within “oil source” rocks. Our findings provide thermodynamic support for the idea that phase transitions involving CO₂, H₂O, oil, and kerogens can occur not only in the kerogen → oil but also in the oil → kerogen direction. The reversibility of phase equilibrium allows us to approach these transitions from an inorganic perspective. Consequently, we can assert that kerogen may be a product of the dehydrogenation of oil and gas. Our experimental results, which investigate the distribution of vanadyl and nickel porphyrin complexes in oils from various productive horizons, support our hypothesis that biomarkers in oils may result from the dissolution and assimilation of dispersed organic matter by ascending, high-temperature hydrocarbon fluids, rather than serving as definitive evidence of a biogenic origin.