Abstract: Many petroleum discoveries which have heretofore been regarded as intractable owing to the immobility of the petroleum can be economically recovered by a process involving local visbreaking of the intractable petroleum in order to produce a medium/heavy cracked gas oil which is injected into a subterranean formation of the intractable petroleum in order to recover the petroleum.

Abstract: A working fluid in the gaseous state at some initial temperature and pressure is expanded polytropically to a resulting exhaust fluid having some lower temperature and pressure in order to produce useful work. Large quantities of a motive liquid are then employed as the vehicle for approximating an isenthalpic compression of the working fluid. The preferred method for effecting this recompression is to reduce both fluids to a single liquid phase which is then energized. Thereafter the two fluids can be reconstituted to their initial states to complete the thermodynamic cycle which, depending upon the fluids selected, can be located in a broad range of the temperature spectrum.