Momentary Static Value of Pressure at the Geothermal Wellhead

Abstract

One of hydrogeothermal structures of Slovakia, denoted as the Levice elevated block, is located in the northwestern part of the Danube Basin. Geothermal water aquifers in the structure are represented by Triassic carbonates and Badenian clastics. The geothermal waters represent the Na-C1 type, with T.D.S. about 19 g/l. A project of geothermal water exploitation in the reinjection system is being prepared for this hydrogeothermal structure. The first reinjection station will be built up at the locality Podhajska. At present there are built up the exploitation well Po-1 with the debit 50 l/s at the free outflow and water temperature 82°C, and the reinjection well GRP-1 with the debit 28 l/s at the free outflow and water temperature 69°C. In the paper there is shown the different in the wellhead pressure development during the exploitation of geothermal and fresh waters which are connected at structures with the confined groundwater level. The calculation of bubble point and of maximum depression, which can be obtained on the well by the exploitation of geothermal water by the free outflow, is explained at the example of GRP-1 well. The maximum depression is defined as momentary static value of pressure at the geothermal wellheads.