NOVELTY - Producing gaseous fuel from biodegradable carbonaceous material involves forming a stacked particle bioreactor from particles of biodegradable carbonaceous material; forming an anaerobic microorganism supporting environment in the bioreactor; anaerobically bio-converting the biodegradable carbonaceous material in the stacked particle bioreactor into a gaseous fuel; and collecting the gaseous fuel from the bioreactor.    USE - For producing gaseous fuel (e.g. methane) from biodegradable carbonaceous material, for converting biodegradable carbonaceous material into synthetic petroleum and/or gaseous fuel, and for bio-converting/converting organic carbonaceous material into fuel (claimed) or a synfuel including e.g. synthetic petroleum oil, alcohol and/or gaseous fuel.    ADVANTAGE - The stacked particles of biodegradable carbonaceous material in the bioreactor, accelerates overall fuel production process by providing large amounts of fatty acids to be converted into fuel such as methane by methanogenic microorganisms in the bioreactor. The method provides a cost-effective way to achieve a very large, high surface area reactor for aerobic and/or anaerobic degradation of carbonaceous materials to synfuel. It is possible to cost effectively scale the method and bioreactor, to process thousands of tonnes of oil shale/sand per day. The method can derive synfuel from low-grade fossil fuels, in low-cost process. The biological method enhances extraction of oil contained in oil sand/shale.    DETAILED DESCRIPTION - Producing gaseous fuel from biodegradable carbonaceous material involves forming a stacked particle bioreactor from particles of biodegradable carbonaceous material; forming an anaerobic microorganism supporting environment in the bioreactor, preferably by purging the stacked particle bioreactor with argon, nitrogen, carbon dioxide, ammonia or hydrogen gas; anaerobically bio-converting the biodegradable carbonaceous material in the stacked particle bioreactor into a gaseous fuel; and collecting the gaseous fuel from the bioreactor. The method further involves aerobically bio-treating the stacked particle bioreactor prior to the formation of anaerobic environment in the bioreactor, to ferment the carbonaceous material in the bioreactor and/or to release native oil from the carbonaceous material. An INDEPENDENT CLAIM is included for a bioreactor for converting biodegradable carbonaceous material into a fuel, comprising several particles of biodegradable carbonaceous material stacked to form a heap having specific void volume, units for communicating gases to and from the heap, a unit for communicating aqueous solutions to the heap, a unit for collecting liquids that drain from the heap, a gas impermeable barrier covering the heap, and a microbial consortium in the heap to biodegrade biodegradable carbonaceous material in the heap to synfuel.