| Abstract [eng] |
The geothermal potential of the Middle Cambrian Pajūrio formation Juozas Bičkūnas Paper for the Master’s degree Geology Master’s Program Vilnius University, Faculty of Natural Sciences, Geology and Mineralogy Department Supervisor – dr. Dainius Michelevičius Vilnius, 2012 SUMMARY The purpose of this thesis is to evaluate the reservoir properties and the geothermal potential of the Middle Cambrian Pajūrio formation in western Lithuania and to produce maps of the effective thicknesses, permeability, temperature and the maximum potential for both horizontal and vertical boreholes. Firstly, a database of 34 boreholes, which had reached the Pajūrio system and were equally spread out in the area, was created. The reservoir properties of the formation have been evaluated using different methods. The shale content was evaluated using gamma-ray logging data, the porosity was calculated according sonic log data. Reservoir thickness was determined according above mentioned interpretation of shale content and porosity. Finally, the values of the permeability of the reservoir layers was taken from the laboratory core analysis. As a result, maps of the reservoir thickness and permeability of the Pajūrio formation were produced using the GeoGraphix software. To produce the temperature map, temperatures from the top of the Cambrian system were taken from the database of Lithuania‘s geological survey. Geotermal potential was evaluated calculating maximum productivities of vertical and 300m length horizontal boreholes. It was found that the geothermal potential in western Lithuania is 2 to 2,5 times bigger in horizontal boreholes as compared to vertical boreholes. The maximum efficiency for vertical boreholes in the area ranged from 0,1 MW (Klaipėda – 1) to 32 MW (Genčiai – 2) and the maximum efficiency for horizontal boreholes in the area ranges from 0,1 MW (Klaipėda – 1) to 65 MW (Genčiai – 2). |
