Patent ID: 8915084

Claim:
A system for extracting heat energy from an underground hydrocarbon reservoir and delivering heat energy to a surface user, comprising: (a) a wellbore comprising a first section extending from a ground surface through overburden to the reservoir and a second section extending from the first section generally within the reservoir; (b) a casing which lines the wellbore and has a sealed end in the second section of the wellbore, the interior of the casing being sealed; (c) a tubing within the casing extending through the first section and the second section of the wellbore, ending prior to the sealed end, and having an open end within the casing in the second section of the wellbore, the tubing having an outer diameter smaller than the inner diameter of the casing, defining a space between the outer surface of the tubing and the inner surface of the casing; (d) an apparatus for injecting a working fluid into one of (i) the space between the casing and the tubing or (ii) the tubing; and (e) an apparatus for receiving heated working fluid from the tubing or the space between the casing and the tubing.