Preliminary study of the geothermal potential of Carboniferous strata in the Pomerania Synclinorium, Poland

Abstract

Exploration and production of oil, gas and coal in Poland has generated a large amount of data on the Polish sedimentary basins. These data contain information of potential importance for the study of geothermal resources. In order to assess the usefulness of these data in geothermal investigations, a case study was made of the Pomerania Synclinorium, a deep petroleum-producing sedimentary basin within the Teisseyre-Tornquist Zone bordering on the Baltic Sea. Existing borehole data from the Pomerania Synclinorium, acquired by the petroleum industry, were used to investigate the geothermal characteristics and potential of this region. The analysis shows that potential geothermal aquifers are present in Carboniferous sandstones at a depth of 2000–4000 m where temperatures range from 60 to 110?C. In one of the wells, Karsina-1, the sandstones are 260 m thick and have a porosity of 16% and a permeability of about 190 mD. These are promising values from the perspective of geothermal utilization. However, due to the variable quality of the available well logs and a mismatch between the logs and cuttings-based lithostratigraphy, it has proven impossible to correlate this stratigraphic interval across the region and establish how regionally extensive the promising reservoir layer is. The usefulness of the existing borehole data is limited due to a lack of standardization, calibration and information about borehole corrections. This needs to be corrected and defective logs deleted from the database before it can become an effective tool in geothermal investigations.