Pyrzyce Geothermy is a high temperature heating plant – the temperature of extracted brine is 64º C, facilitating direct use of the earth heat, which source is deposit geothermal water, filling the pores and crevices of rocks as brines of various degree of concentration. The heat from extracted thermal water is taken, and then after given the heat to water in heat exchanger, thermal water flow the pipeline to alloted injection wells GT-2 and GT-4 and there is cooled to a lower temperature. The depth of wells is 1640 m. Thermal water near Pyrzyce is highly mineralized (121 g/l, mainly NaCL).
Pyrzyce Geothermy, like most of Geothermal Heating Plants has problem with holding high productivity exploitation of thermal water. The basic problems of injection wells are progressive loss of productivity and efficiency of pumping and fast corrosion.
Four out of five Geothermal Heating Plants of high enthalpy water, functioning in the area of Poland, struggle with problem of assurance appropriate productivity assuring smoothness their action. Decrease of productivity and efficiency of the pumping and fast corrosion are related to injection wells problem.
The problems with pumping cooled thermal water back into indigenous ground water by injection wells are not only problems of polish Geothermal Heating Plants. These problems are in Europe and in the world in all Heating Plants pumping cooled thermal water back into indigenous aquifers and especially to pore collectors.
The problems in other countries
In Germany just like in Pyrzyce thermal water have very high mineralization. Mineralization in Neustadt-Gleve is 227 g/l and in Unterhaching about 100 g/l. The geothermal system in Neustadt-Glewe is an example of research on the soft acidizing method in order to repair the well and restore the absorbtion, which has decreased as a result of usage in the effect of the development of corrosion and precipitation. Similar problems also have other German Geothermal Heating Plants.
In Bad-Blumau, due to anxiety about colmatation of the injection well, inhibitors with cooled thermal water are injected. Utilized thermal water is injected back into the depth of 3000 m and its mineralization is 17,9 g/l.
Beeing the subject of the demonstration, the method of super soft acididizing is the modification of the soft acidizing method, which was tested in Paris basin.
It may also point to problems with pumping cooled thermal water in French Geothermal Heating Plants. The heating plants exploiting here mainly Doggerian limestones (Middle Jurassic). Mineralization of these water oscillated in the range of 5-35 g/l. Exploitation of seams for heating purposes is run with doublets (in some cases with triplets ) relatively deep (1,5 - 2,5 km) wells, with the injection of cooled thermal water back into the reservoir). Due to the chemical composition of geothermal water, they have highly corrosive properties what escalating problems connected with exploatation the French Geothermal Heating.
The problem with injection cooled thermal water is in the geothermal fields in the Geysers in USA, where in the deposit layer are located geothermal steam. To make it available, it was made 400 geothermal wells to 3200 m depth.
After give its energy the turbine the geothermal steam is condensed and again pumped to formation by 70 injection wells. In this case it can only pumped only 25 percent all condensed geothermal water.
At present there are leading intensive work, associated with improvement of absorption of the injection wells. Increasing the efficiency of injection condensates is necessary due to preservation of renewable the source.
Previous researches and gained experience include:
Pyrzyce Geothermy to improve the absorption of the geothermal deposit layer introduced following methods of cleaning the injection wells: