| Abstract |
By convention, low to medium enthalpy geothermal resources, eligible to geoheat and cold and combined heat and power production, are classified according to depth. Shallow geothermal sources supply heat and/or cold via surface heat pumps and either borehole heat exchanger or groundwater doublet systems. Deep seated geothermal deposits address larger, preferably dependable, sedimentary reservoir environments and higher heat loads provided by district and greenhouse heating uses. Development forecasts in Europe for geoheat and cold production stand in year 2030 at 260 GWt (installed capacities) and 380 TWht (yearly production), achieving a 5 to 3 growth ratio from now on. For Europe alone (EU 28), 1.80 GWt and 260 TWht/yr are projected, implying dramatic, eight and five fold, growth ratios respectively, indeed a challenging objective. This problem is analysed in the light of the European resource environments, available knowhow/best practice and foreseeable technological improvements, from a reservoir engineering standpoint. In so doing the present paper focuses on the deep geothermal segment which displays distinctive reservoir settings and farming technologies, bearing in mind they often share common resource management and environmental concerns with shallow geothermal practice. Accordingly, the most rewarding contributions in the areas of well architecture, water injection, geomodelling, advanced heat pump technology, combined heat and cold production and storage, reservoir longevity are reviewed and their implications on sustainable reservoir management strategies discussed. |