Hi,
No that isn't the case. The amount of heat stored is absolutely massive and would take around 20,000 years for 1% of the Paralana heat to be utilized. What does happen is that the local heat may diminish so new wells need to be drilled from time to time. But in many ways the decay of the radiogenic granites is analogous to a nuclear reactor... in fact it has been dubbed nature's nuclear reactor in several articles.
"if a low estimate of 1% were taken, Australian geothermal sources could provide 26,000 years of energy supply."
https://www.australianminesatlas.gov...he/GA10323.pdf
The KUTH Energy heat source might not need the new drill holes as they probably have a Hot DRY Rock - wet aquifier (HSA)
The various models being explored here in Australia can be seen here:
http://www.hotrockenergy.com/images-...y-systems.html