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Description
The potential of geothermal energy in the Town of Križevci arises from its location in the area of the former Pannonian Basin, geological structure and favorable geothermal gradient. In the area of the City of Križevci, there is a geothermal well Križevčanka-1, the existence of which has been determined by previous research. The aim of the project is to perform exploratory oil and mining works in the existing geothermal well Kža-1, conduct planned trial operation for hydrodynamic and laboratory tests to determine the characteristics of the reservoir and define the parameters of the reservoir required for the study in the reserves. Energy purposes for heating existing publicly owned facilities located in the immediate vicinity of the existing well.
Summary of project results
The aim of the project was to carry out exploratory oil and mining works in the existing geothermal well Kža-1, to carry out planned trial exploitation for the purposes of hydrodynamic and laboratory testing in order to determine the characteristics of the reservoir and define the reservoir parameters necessary for the preparation of the Reserves Study, as well as the future possibility of using it for energy purposes for heating existing publicly owned facilities located in the immediate vicinity of the existing well.
1. Establishment of a geothermal energy utilization system in Križevci - hydrodynamic testing
Before the start of hydrodynamic measurements, a measurement of temperature and pressure in the well was made under static conditions. The measured temperature at the reservoir level was 90.4 degrees Celsius, while the static pressure at a depth of 1440 meters was 141 bar. After the static measurement, a centrifugal pump (ESP) was installed in the well on a string of tubing and it was started for the purpose of trial production on 25.03.2024. The well was tested under 4 production conditions at depths of approximately 300 and 500 meters of the centrifugal pump suction installation depth in the period from 25.3.2024 to 27.3.2024. At a depth of 300 meters, by adjusting the pump frequency, a hydrodynamic measurement was made at a flow condition of 5 l/s and 7.4 l/s. In both conditions, the level above the suction stabilized and the measurement continued for 4 hours after stabilization with a constant dynamic fluid level in the well and an increase in the temperature of the produced fluid at the wellhead. At a depth of 500 meters, by adjusting the pump frequency, hydrodynamic measurements were made at flow conditions of 15 l/s and 9.5 l/s. In both conditions, the level above the suction stabilized and the measurement continued for 4 hours after stabilization with a constant dynamic fluid level in the wellhead and an increase in the temperature of the produced fluid at the wellhead. The fluid temperature at the surface reached 79.6º C.
2. Project management and administration
Preparation of project documentation, organization of activities, project management, reporting and coordination of project partners and gaining experience in managing and conducting geothermal projects through the organization of a study trip to Norway, where partners from Croatia met with experts who manage geothermal systems in Norway.
3. Promotion and visibility
Informing citizens, business entities, professional and sectoral organizations, the professional and scientific community, civil society, the media and the general public about the project.
The project ensures the achievement of the long-term strategic goal of the City of Križevci related to the geothermal potential of the Križevci area, so that the existing well can be put into operation, which will affect the well-being of all target groups.
Summary of bilateral results
The bilateral partnership significantly contributed to the implementation of the project and the resolution of the problems we encountered during implementation due to the extensive experience of the project partners from Iceland in the use of geothermal energy, which broadened our way of thinking.