They are not fossil fuels

Why natural gas and oil can be considered inexhaustible

For long periods of time, millions of years elapsed, long before the appearance of the human species, on the Earth's surface there were numerous hydrocarbon, gaseous, liquid and viscous surges. Hydrocarbon fluids emanated in the fumaroles and mud volcanoes to which were added gas leaks from volcanic eruptions and hyperthermal underwater emissions.
The fluids come out when the pressure exerted on the seal rock (the superimposed rock, which is above it) is greater than the weight of the mass.
In other words, there is no rock that can maintain a liquid that comes out with a pressure greater than that exerted by the weight of the overload.
A seal rock will give rise to a concentration of the fluids below it, but over time this concentration will come to exert a rising pressure greater than the weight of the overlying rock layers. At that time the upward flow will be restored to a value equal to the flow velocity at the depth source.
All available data tend to show that the theory of "fossil" origin is, at least, unsatisfactory.
Here we are talking about a very deep source (perhaps hundreds of kilometers, in the earth's mantle) and therefore we are considering very large volumes, something like 5 to 10% of the volume of the terrestrial mantle
Abiotic hydrocarbons
According to the vision of several Russian and Ukrainian oil geologists and the astrophysicist Thomas Gold, oil and gas result from the geological degassing of the planet that began at least 3,000 million years ago and continues today.
Existing oil and gas volumes would constitute a very high percentage of the planet's mass, with quantities much higher than currently estimated (perhaps hundreds or thousands of times greater). In otheA words, for all the purposes of our arrogant human civilization, oil and gas stocks would be inexhaustible.
This means that gas and oil are not going to end (at least in the next thousands of years) and that the main limitations for human societies could be the difficulty of accessing the deposits and their potential environmental impacts in the atmosphere, but not the exhaustion of "reserves". These impacts would include the increase of carbon dioxide (which could lead to a possible greenhouse effect, which is not yet proven) and the decrease in the percentage of oxygen contained in the air (much more serious, although its effects do not seem imminent) .
Another consequence of the theory is that there may be accumulations or oil and gas emanations on the entire surface of the planet. Of course there are areas where the presence of fractures and structural traps allow or allowed the accumulation of large volumes of hydrocarbons and there are the largest and most accessible deposits. However, it is possible to wait for the upwelling of hydrocarbons in ALL the fractured zones of the crust, especially in the periphery of the mountainous regions, in the zones of faults, in the continental borders, and of course in all the sedimentary basins that allowed the trapping of ascending hydrocarbons (for example, in the Gulf basins in the Middle East) there are stocks or possibilities of deposits or emanations of hydrocarbons, oil (liquid) and above all natural gas.

This topic was developed in depth in the following book:
- Inexhaustible? Oil and Natural Gas; Danilo Antón, Piriguazú Ediciones, Montevideo, 2006.