Shallow geothermal heat in Western Canada: climatic warming impact changes with timedepth

The gain in heat and temperature in the shallow subsurface over the last decades/century has been caused by the industrial-period increase in climatic surface air temperature (SAT). A detailed study of the available temperature-depth data based on 43 wells with single and repeated temperature logs done by the first author has been combined with database information (Jessop et al. 2005) to create temperature maps at depth. Based on these 43 logs, it is shown that the heat flux increases with depth in most cases for the available depth data range from surface to similar to 200 m. A model of heat flow versus depth based on surface air temperature changes through the industrial-period climatic warming explains the data. The spatial and depth distribution of available temperature and heat gain through the provinces of the Western Canadian Sedimentary Basin WCSB shows that drilling closer to the surface is more economic than drilling deeper to 50-100 m.