Abstract: A method of converting organic waste into useful petroleum products and for recovering previously unrecoverable residual oil in oil bearing geologic layers. An organic slurry containing obligatory anaerobes is first formed from garbage, sewage and the like to which may be added various catalysts such as iron or cobalt. The slurry is then pumped into a geological layer, which is preferably oil bearing, having a temperature of a magnitude which allows anaerobic digestion to continue. One or more explosive devices are positioned above the geological layer and below an explosion directing cap. After a period of anaerobic digestion, the explosive devices are detonated causing heat and pressure to be applied to the organic waste in the geological layer. The combination of heat and pressure cause various chemical reactions, including molecular restructuring, to occur which convert the organic waste into various petroleum products.