I've always been intrigued by the possibility of oil having been formed by non biological processes. Especially since there are trillions of tons of methane out there in space such as on Saturn's moon titan. It stands to reason that there could be non-biological processes which are capable of converting methane into longer chain hydrocarbons.
Now some scientists at UC Davis, Livermore National Labs and Shell Oil Corporation have created a theory and functional computer based model which shows that long chain hydrocarbons could be formed at extreme pressures and temperatures under the Earth's crust at a depth of about 70 kilometers.
That said, as interesting as the science of this is, it in no way changes the fact that we have a flow problem: even if abiotic oil were real, then if we extracted it far faster than it was created, we'd still hit peak oil. So it's not a solution to declining production, just an interesting tidbit of science.