Quantification of resources and localisation of most promising areas for geothermal prospecting are today key tasks for the development of geothermal energy. Such an analysis was lead for the Canton of Zürich, for surface geothermal energy (borehole heat exchangers and surface groundwater) and for deep geothermal energy (doublet systems). The first step of the work consisted in regrouping geological datas (from well, geological cross section and 2D seismic profiles essentially), hydrogeological datas (hydraulic conductivities of different layers derived from well tests) and thermal datas (estimation of thermal conductivities of layers, mean surface temperature and borehole temperature logs). In a second phase of the project, 3D numerical models were built in order to compute temperature in the underground, relying on a simplified geological model and on thermal datas acquired in the first phase of the project. Then, temperature of the identified aquifers has been extracted from the 3D models, and the geothermal potential of such target horizons could be calculated (Gringarten, 1978).
As a result, maps showing the temperature, depth and potential of geothermal energy of different identified aquifers the over the Canton were built, and the total amount of available and recoverable energy was estimated.