viable geothermal energy supply from exhausted fracked gas wells? The UK legislator with primary responsibility for energy has claimed that exhausted fracked natural-gas wells will be suitable for re-use as a geothermal energy supply (not necessarily geothermal for electricity production, but rather for heat distribution, so let's say 80&deg; - 250&deg;C).

Is there much of a co-location of the geo-thermal resource in the UK, with the more easily obtained frackable natural gas; and would an exhausted fracked well be structurally suitable for this?
Viability of an oil or gas well for geothermal energy production is dependent upon several factors:
 - Geothermal heat profile with depth near the well 
 - Depth of the exhausted well
 - Volume of fluid acting as a heat exchange around and near the well.

I think it might be possible to use exhausted natural-gas wells will be suitable for re-use as a geothermal energy supply. Likelihood of success would require site investigation and the engineering pilot study.  This idea would be ideal for university engineering / geology research.