Modelling geothermal conditions in part of the Szczecin Trough – the Chociwel area

摘要

The Chociwel region is part of the Szczecin Trough and constitutes the northeastern segment of the extended Szczecin-Gorzów Synclinorium . Lower Jurassic reservoirs of high permeability of up to 1145 mD can discharge geothermalwaters with a rate exceeding 250 m 3 /h and temperatures reach over 90°C in the lowermost part of the reservoirs. Theseconditions provide an opportunity to generate electricity from heat accumulated in geothermal waters using binaryORC (Organic Rankine Cycle) systems. A numerical model of the natural state and exploitation conditions was createdfor the Chociwel area with the use of TOUGH2 geothermal simulator (i.e., integral finite-difference method). An anal-ysis of geological and hydrogeothermal data indicates that the best conditions are found to the southeast of the townof Chociwel, where the bottom part of the reservoir reaches 3 km below ground . This would require drilling two newwells, namely one production and one injection. Simulated production with a flow rate of 275 m 3 /h, a temperature of89°C at the wellhead, 30°C injection temperature and wells being 1.2 km separated from each other leads to a smalltemperature drop and moderate requirements for pumping power over a 50 years’ time span. The ORC binary systemcan produce at maximum 592.5 kW gross power with the R227ea found as the most suitable working fluid. Geothermalbrine leaving the ORC system with a temperature c. 53°C can be used for other purposes, namely mushroom growing,balneology, swimming pools, soil warming, de-icing, fish farming and for heat pumps.