Futhermore, oil often ends up blocked by some impermeable capping layer, having migrated under pressure from somewhere below. Thus, I'm not sure how you know when it was formed unless it's some kind of isotope dating.
I have a book, Seven Clues to the Origin of Life that talks about the tar problem in abiogenesis. This is not a done deal, but it would be interesting to find that petroleum can form without life.