Don’t claim to have all the answers, but we probably have the early stages of coal and possibly oil/gas production going on right now in peat bogs around the world. Here’s the Wiki entry for peat.
http://74.125.113.132/search?q=cache:5M4ai7XvIEgJ:en.wikipedia.org/wiki/Peat+peat&cd=1&hl=en&ct=clnk&gl=us
We’re talking very large volumes.
I am fully open to the idea of abiotic production of natural gas and somewhat less so to oil. Coal it seems pretty clear is fossil in origin.
Coal, by itself I could accept. But when you add the mass of vegetation required for coal, gas, peat, oil, and anything else, I have a hard time grasping All the SUDDEN trappings of organic life, in such large quantities, at so many different times.