GIGO
“Fossil” oil is abiotic
This planet is full of carbon based life, it dies, and recycles for our usage. As long as the circle of life keeps on having a termination point, there will be fuel from the ground.
Fossil oil is primarily made from dead insect carcasses. The inclusion of dead carcasses of dinosaurs in the 'cooking' of oil deep in the Earth is what causes 'dirty crude'.
On a related but much ignored subject, all our plant food is grown in dirt that is primarily worm poop.