I think I usually just use generic terms like oil, natural gas, or petroleum. I have read various hypotheses as to the origins of fossil fuels, but I am not familiar enough with that field of science to even make an educated guess on the topic.
Good enough. I’m not skilled in oil except those chem and engineering classes years ago. Using an odd misnomer that oil came from dead foliage and dinosaurs as fact( I was taught this in school)has to be put at rest. I call oil Dino-juice and the green folks have no idea I’m using sarcasm.