If it is that hot down at the bottom - ~200 degrees C depending on where the bottom is, is there no way to economically generate power with some type of steam turbine dropped down the hole? If you could get the steam turbine to power the drill then you could make it all the way to 'China' by teatime...
I believe the last time something like that was contemplated the analysis was that the energy you could extract would make for very very slow going (not surprisingly it requires a lot of energy to bore through rock and remove the excess). Assuming a return pipe to the surface the deeper it is the higher the boiler pressure you can support since you can use the cold water return column to pressurize the feed. Of course at some point your at the limit of your boiler as well.
Not a heat pump, simply a heat engine (if you're taking the work) or heat source (if you're using the heat). "Pumping" implies going against the gradient.