Method of recovering oil from oil shale

Claim 1

AN IMPROVED METHOD OF DESTRUCTIVELY DISTILLING OIL SHALE IN SITU BY USING A COMBUSTIONSUPPORTING GAS CONTAINING CARBON DIOXIDE AND OXYGEN IN A CRITICAL RATIO WHICH COMPRISES ESTABLISHING A COMBUSTION WELL EXTENDING FROM THE SURFACE OF THE EARTH TO AN OIL SHALE STRUCTURE, ESTABLISHING AN EXHAUST WELL ADJACENT TO SAID COMBUSTION WELL TO PERMIT WITHDRAWAL OF HYDROCARBONS DESTRUCTIVELY DISTILLED FROM OIL SHALE IN SAID STRUCTURE, PRODUCING AN EXPLODED ZONE AT THE BOTTOM OF SAID COMBUSTION WELL AND A COMBUSTION ZONE OF FACILITATE COMBUSTION OF HYDROCARBONS IN AND DESTRUCTIVE DISTILLATION FROM SAID OIL SHALE, EFFECTING COMBUSTION IN THE BOTTOM OF SAID COMBUSTION WELL WITH AN OXIDIZING GAS MIXTURE CONTAINING CARBON DIOXIDE AND OXYGEN, CONTROLLING THE OXYGEN-CARBON DIOXIDE RATIO IN SAID GAS MIXTURE IN SAID COMBUSTION WELL TO PROVIDE A CARBON DIOXIDE CONTENT ABOVE 20% IN SAID GAS MIXTURE AND TO PRODUCE A RELATIVELY LOW AND REGULATED TEMPERATURE BELOW ABOUT 1000* C. IN THE COMBUSTION ZONE OF DESTRUCTIVE DISTILLATION AND TO C. IN THE ZONES OF DESTRUCTIVE DISTILLATION AND TO PRODUCE AN EXHAUST GAS IN THE EXHAUST WELL CONTAINING ABOVE 80% OF CARBON DIOXIDE THEREBY PROMOTING THE EVOLUTION OF HYDROCARBONS, WITHDRAWING SAID EXHAUST GAS CONTAINING VOLATILE HYDROCARBONS AND CARBON DIOXIDE FROM SAID EXHAUST WELL, AND RECOVERING SAID VOLATILE HYDROCARBONS WHEREBY GREATER YIELDS OF VOLATILE HYDROCARBONS ARE RECOVERED FROM SAID OIL SHALE WHILE AT THE SAME TIME THE SPENT SHALE IS PREVENTED FROM SLAGGING AND THE CINDER IN MAINTAINED POROUS TO SAID GAS MIXTURE.