When will oil and natural gas run out? 

The answer to this question depends on the theory we accept about the origin of oil and natural gas.

First of all, let us clarify that both oil, or rather, the different types of oil, and natural gas, made up of methane, ethane and other alkanes, are hydrocarbons, that is, compounds of carbon and hydrogen with some impurities.

If we consider that the origin is biological, that is, the accumulation of organisms, which is incorrectly called fossil hydrocarbons, both the existence of oil and natural gas would be limited to sedimentary basins.

In other words, it would be limited to a thin discontinuous layer on the earth's surface, a layer that generally has a thickness of a few hundred meters or at most several kilometers, which is something like one thousandth of the earth's radius.

The extension of these sedimentary basins is approximately 10 to 20% of the planetary surface, or about 50 to 100 million km2 depending on the criteria used to classify them.

Sedimentary basins are formed by accumulations of strata or layers that in some cases are permeable or fractured and in those cases have the capacity to contain hydrocarbons such as oil and/or natural gas.

It usually happens that the hydrocarbons formed in the mantle and at the base of the crust tend to rise due to their lower density than water and the host rocks. It must be remembered that both oil and natural gas are lighter than water, which is the fluid that is almost always present in the sedimentary subsurface.

In these cases, the permeable or fractured sedimentary formations that I mentioned earlier may be the receptors for the ascending hydrocarbonaceous fluids.

It is also important to point out that accumulations of oil and natural gas also depend on the existence of impermeable layers that can retain fluids and prevent them from escaping to the outside.

Considering that more than 30,000 million barrels of oil are extracted each year, that is, 4,700 million metric tons and 4 billion m3. of natural gas and that this extraction has existed for several decades, it can be estimated that under the terms of the biotic oil theory its exhaustion is possible even soon. I clarify that this conclusion can only be reached if we think that oil and gas are formed and only exist in sedimentary basins.

Always according to this biogenic and restrictive theory, we can think that if the extraction continues with a similar intensity, the existing deposits could be exhausted in the near future, let's say a few years or tens of years.

However, if we accept the theory of the mineral origin of hydrocarbons, the forecasts would be very different.

In the first place, the origin of oil and natural gas would take place in the upper portion of the Earth's mantle at a depth of 100 to 300 km. That is where the conditions are met for carbon and hydrogen to combine in a stable way.

That situation would be more or less continuous and would extend to the entire planet at that depth. The natural evolution of the crust would lead these fluids to rise for a long time, for example millions of years through fractures that are sometimes generated in the crust, and end up getting trapped in their ascent if they find impermeable layers. Under these conditions, deposits of both natural gas and oil can be formed.

To the above, it must be added that there are deposits in exploitation for a long time, even some that are about to be exhausted could be recharged due to the rise of fluids from lower levels.

According to this theory, the mineral or abiotic theory, the volumes of existing hydrocarbons would be at least two or three orders of magnitude higher than what would be expected if the hydrocarbons originated from organic remains.

The final conclusion is that in that case there would be no problems of depletion of oil or natural gas, and that if there were problems they would only be related to strategies or techniques related to extraction.

Indeed, although the volumes available may be almost inexhaustible, in any case, for the effective extraction of oil and natural gas there are several preconditions.

First of all, the deposits must be located. This may require geophysical studies, drilling and investments that allow reaching the exploitation of the deposits. Some deposits have technological limitations due to geological structural conditions and may require technological innovations for their exploitation to be possible.

And finally, for the decisions and exploitation plans to be carried out, governments and companies need to make economic and political decisions that are not always taken.

In other words, thinking in terms of abiotic hydrocarbons, production problems and even depletion