These comments seem to indicate that you have paid no attention to what I actually said, or the links I gave. To repeat: some oil forms quickly, some forms slowly. The actual point I was making was not about how oil forms but about the amount of biomass contained within carboniferous deposits in the earth. It is impossible for all of it to have got there in just a few thousand years. Again to repeat, that much carbon being readily available in the biosphere would dwarf the amount that is currently causing concern for climate change.