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.
I think that's because there is a lot of 'hard' science in this thread. As I am both mathematics and chemistry-challenged, I have been gritting my teeth reading this thread, worried that carbon-bonds and all sorts of organic chemistry that is way, way over my head was going to come gushing out beyond a wildcatter's dream.
Biology and evolutionary biology are actually just as 'hard' as organic chemistry--but everybody (even Creationists) think they 'understand' it because we are the subject matter.
...I was about to point the fallacy in this assumption using an analogy (Creationists love analogies) about asking guinea pigs to explain how the Skinner maze works--but no, let's not do that, it's a cheap shot :-)