Hydrocarbons, such as oil and natural gas, are primordial and metastable compounds that come from high pressure and temperature environment deep inside the Earth. These volatiles were trapped on the planet during accretion processes and there are huge amount of hydrocarbons within the Earth. Tectonic forces enables the migration of hydrocarbons from mantle to shallower crustal levels aided by carrier gases such as helium and nitrogen, mainly in sedimentary basins, where can form commercial accumulations. There, a deep biosphere formed by microorganisms, can rework these abiotic and primordial compounds causing biodegradation and leave their traces as biomarkers after eat and die into primordial and abiotic oil. The propositions of the scientist Thomas Gold, according to Deep-earth Gas Theory and Deep Hot Biosphere, have solved the the petroleum paradox and scientifically explain many chemical and physical processes related to natural hydrocarbons.
Molecules of biological origin have low chemical potential and in accordance with laws of thermodynamics could not transform spontaneously into hydrocarbons heavier than methane, which are molecules of high chemical potential. Studies of thermodynamic stabilities and free energies of Hydrogen-Carbon system conducted by Dr. J.F. Kenney clearly demonstrate the impossibility of biological organic matter form natural hydrocarbons. Biological molecules in general are oxidized, such as carbohydrates and never could form oil.
There are a lot of carbon on Earth's surface, but almost all hydrocarbons come from deep outgassing of the planet and this carbon undergoes dynamic changes in external systems of the lithosphere, hydrosphere, biosphere and atmosphere. The organic matter of biological origin also has low rate of preservation, either by the attack of microorganisms or mainly by oxidation processes that tend to destroy it.
Thinking that, for example, that the jet engines which raise a plane in the air and their strength would be driven by "fossil fuels" is a silly notion.
“The suggestion that petroleum might have arisen from some transformation of squashed fish or biological detritus is surely the silliest notion to have been entertained by substantial numbers of persons over an extended period of time.” — Sir Fred Hoyle, 1982
Understanding the real nature of the origin of petroleum, natural gas and black coal surely will allow a great breakthrough in the understanding of geological processes.
A more detailed description of the origin of natural hydrocarbons based on scientific reasoning of important scientists and several evidences supporting abiotic oil theory can be found in the link below: