Patent ID: 8261823

Claim:
A system for producing hydrocarbons in situ from an oil shale, fixed bed hydrocarbon formation disposed below a ground surface and having a naturally occurring, water-flow leached, higher permeability zone next to a lower permeability zone, the system comprising: at least one injection opening in the naturally occurring, water-flow leached, higher permeability zone of the hydrocarbon formation, the injection well having a first vertical depth; at least one production opening in the higher permeability zone of the hydrocarbon formation, the production opening having a second vertical depth, the first vertical depth of the injection opening approximately the same depth as to the second vertical depth of the production opening, the same depth of the injection opening and the production opening providing horizontal communication therebetween; a heated thermal-energy carrier fluid injected into the injection opening and circulated horizontally through the higher permeability zone and parallel thereto, the carrier fluid pyrolyzing hydrocarbons in the lower and higher permeability zones in situ by heating the higher permeability zone and the adjacent lower permeability zone along an interface extending substantially between the injection opening and the production opening, and producing at least a portion of the mobilized hydrocarbons by flowing the carrier fluid with the pyrolyzed hydrocarbons through the production opening to the ground surface; and means for removing at least one selected hydrocarbon held in the carrier fluid.