Geothermal Reservoir Analogues on a Continental Scale – Western Canadian Sedimentary Basin Versus Northern Alpine Molasse Basin

Abstract

The public utility company of the city of Munich, Germany (Stadtwerke München, SWM) develops geothermal heat usage for district heating from geothermal sources. The municipality of Munich, which is a major shareholder of SWM, decided to terminate heat generation from fossil fuels and to supply all remote heat from geothermal sources, notably from the Jurassic Malm carbonate aquifer in the Northern Alpine Molasse Basin (NAMB). This study intends to qualify, whether thermo-physical, thermo-facial, and structural knowledge from the Malm aquifer can be transferred to and/or interchanged with similar data from Devonian carbonate aquifers in Alberta, Canada, and to which extent this is useful. In Alberta, a vast number of oil and gas wells drilled in the Western Canadian Sedimentary Basin (WCSB) is available to be evaluated for geothermal utilization, yet there is no utilization of deep geothermal resources at this time. In contrast, few wells have been drilled in the German Molasse Basin that contains the Malm aquifer. Thus, Germany is in need for much more detailed reservoir assessment to intensify the ongoing geothermal utilization. This circumstance forms the basis for our study, in that ample core material from the Upper Devonian carbonate aquifers, which are promising target formations for geothermal energy utilization, is investigated and compared to cores from the Malm aquifer. Samples from prominent carbonate formations were analyzed for thermal conductivity, thermal diffusivity and heat capacity, as well as density, porosity and permeability. Furthermore, open-file petrophysical core data retrieved from the AccuMap database were used for correlation. Structural und thermal similarities between the German Molasse Basin and the Canadian Rocky Mountain Foreland Basin are obvious. The question is: can exploration data and experience from research in these two regions be exchanged and utilized for mutual benefit? The worldwide trend of increasing CO2-emissions could be significantly reduced if alternative and/or renewable energy sources were implemented to a larger degree.