Recovery of Hydrocarbons From Oil Shale Deposits

This invention relates to recovering hydrocarbons from oil shale preferably in-situ where the temperature of the oil shale deposit is controlled to maximize recovery of hydrocarbons and minimize decomposition of carbonate minerals into carbon dioxide that might be released into the atmosphere. The process includes generating heat from hydrocarbon gases recovered from the oil shale and then later performing a controlled burn of the char that is left in the spent shale after the kerogens have been thermally cracked and the most of the recoverable hydrocarbons have been recovered. The burning of the char is also controlled based on the temperature of the oil shale in-situ, the temperature of the gases retuning to the surface from the oil shale and the carbon dioxide in the gases returning to the surface.