Abstract: A method and apparatus for efficiently extracting geothermal energy from a subterranean thermal reservoir through a wellbore where the heat exchange fluid is introduced at a slower velocity than the velocity at which the fluid is extracted. The method and apparatus further comprises a region void of cement between the outer wall of a casing and the inner wall of the wellbore, such that thermally conductive material can be injected therein.

Abstract: A method and apparatus for efficiently extracting geothermal energy from a subterranean thermal reservoir through a wellbore where the heat exchange fluid is introduced at a slower velocity than the velocity at which the fluid is extracted. The method and apparatus further comprises a region void of cement between the outer wall of a casing and the inner wall of the wellbore, such that thermally conductive material can be injected therein.

Abstract: A method and apparatus for extracting geothermal energy from a subterranean thermal reservoir through a wellbore where the heat exchange fluid is introduced at a slower velocity than the velocity at which the fluid is extracted. The method and apparatus further comprises a gas zone near the top of the wellbore to maintain the thermal energy of the heat exchange fluid. In one embodiment, a portion of the casing of the wellbore can directly contact the subterranean environment. Alternatively, a thermally conductive wall comprising a thermally conductive material can surround a portion of the casing of the wellbore. Further, the inner and/or outer surface of the pipes and conduits of the disclosed method and apparatus can include modified surface features that influence the flow and/or thermal conductivity of the heat exchange fluid.

Abstract: A method and apparatus for efficiently extracting geothermal energy from a subterranean thermal reservoir through a wellbore where the heat exchange fluid is introduced at a slower velocity than the velocity at which the fluid is extracted. The method and apparatus further comprises a gas zone near the top of the wellbore to reduce heat losses of the heat exchange fluid. A portion of the casing of the wellbore can directly contact the subterranean environment for improved thermal conductivity. Alternatively, a thermally conductive wall comprising a thermally conductive material can surround a potion of the casing of the wellbore. Further, the inner and/or outer surface of the pipes and conduits of the disclosed method and apparatus can include features that enhance the surface areas for improved heat transfer efficiency.