There are two competing theories about the origin of petroleum and natural gas: The "fossil theory", which is the conventional wisdom in the West, and the "abiotic (ie non-biological) theory", which is scientific orthodoxy in Russia and the Ukraine.
The first says that oil is the result of pressure and other factors working upon organic matter (both zoological and botanical) – prehistoric forests and the corpses of long dead animals.
The second says that geological forces way way down continually generate oil out of inorganic material. In support of this theory they point out that there are instances of dried out wells which have been replenished. What is more, astronomers have detected hydrocarbons (chemicals similar to petroleum) in comets – no rotting dinosaurs up there, I think.
I have read that oil prospectors in the West have a 20% success rate, whereas their Russian counterparts achieve 70-80%. The latter have found oil at 30,000 feet (maybe more) – far too deep for prehistoric forests and the corpses of long dead animals.
Estimates of oil reserves are constantly revised upwards. Alarmists say we have only a few years' worth left. Their opponents say there is enough down there for 500 years, or maybe for much longer.
Thomas Gold (now deceased) is a scientific hero of mine. Three times he found himself in the academic wilderness:
- He proposed a theory of hearing which said that our ears emit a sound and that it is the interference with this sound by external sound waves which is processed by our nerves and brains. Nobody wanted to know. Now scientists have identified individuals where the noise is detectable and the theory has enjoyed a renaissance. Anyway, Gold was discouraged and went off to do Cosmology.
- He proposed a theory to account for pulsars, astronomical objects which produce regular pulses of energy. He said that pulsars were pairs of (binary) stars which rotate about each other. Nobody wanted to know. His theory is now mainstream.
- He and his collaborators proposed that oil did not come from fossils but from geological processes.
The Russians are totally convinced that he was right. I think there was some controversy about alleged plagiarism. Western scientists have not yet followed suit. He did not get credit in his lifetime. I hope Duesberg lives to be vindicated.
This link is to a site where the controversy is discussed in some detail, with arguments from both sides.