Influence of the Joule-Thompson Effesct on Geothermal Energy Production at the Reservoir Velika Ciglena

Geothermal reservoir Velika Ciglena is placed 11 km south-east from the city Bjelovar. It is the high-temperature reservoir, according to the physical characteristics of rocks. So far, four wells have been made. Optimal production of the geothermal energy can be obtained on the well VC-1A, due to the production equipment and thermodynamic conditions of the reservoir. The well is 2881 m deep, with the static pressure of 247, 3 bar and the static temperature of 175°C. Production layer is located on the 2 543 m. The geothermal water production should flow through the annular space between the tubing and the casing, which are designed for the wellhead pressure of 20 bar. Calculations shows that the temperature of the geothermal water on the wellhead should be about 170°C, if the flow is 10 000 m3/h, based on the Duns-Ros methodology. In determination of the optimal temperature, the Joule-Thompson effect should be applied, as it strongly influences all gases and liquids, being important for geothermal water as well.