The quality of geothermal reservoir of the Lower Jurassic aquifer in the Mogilno-Łódź Trough (Polish Lowlands)

The assessment of the geothermal potential should always take an accurate identification of the geological conditions into account. Petrographic and petrophysical investigations of the aquifers allow to estimate their productivity and infectivity. The area of the Mogilno-Łódź Trough is next to the Podhale basin, one of the most prospective regions in terms of geothermal potential in Poland. The Lower Jurassic aquifers are characterized by the largest dispositional resources among geothermal aquifers in the Polish Lowlands. The Lower Jurassic geothermal reservoir consist of fine and mixed grain-size sands and sandstones layers from 10-650 m thick, depending on the depth. The water within the reservoir exhibits mineralization ranging from 2 to over 250 g/L and its temperature ranges from 30 to 100°C. Boreholes profiles selected for study consist Lower Jurassic formations of the Polish Lowlands, which are perspective for the heat production in Poland. Sandstones are represent mainly by quartz arenites and subordinate by quartz wackes. Parameters measured include among others porosity, permeability and surface area. The results of the petrographic and mineralogical studies of core samples confirmed the presence of rock with favorable parameters for geothermal water accumulation.