Experimental Rock Characterisation of Upper Pannonian Sandstones from Szentes Geothermal Field, Hungary

The Upper Pannonian (UP) sandstone formation has been utilised for thermal water production in Hungary several decades. Although sustainable utilisation requires the reinjection of cooled geothermal brine into host rock, only a fraction used is reinjected country. UP reported to exhibit low injectivity, making challenging, and its petrophysical properties are poorly known, which increases uncertainty designing operational parameters. goal study provide experimental data gain better understanding characteristics that control injectivity productivity issues layers. Petrographical characterisation laboratory experiments conducted on cores retrieved from two wells drilled framework an R&D project at depth between 1750 m 2000 m. experiments, such as grain density, porosity, permeability, ultrasonic velocity, well thin section, size distribution, XRD, SEM analyses, determine Petrophysical Rock Types (PRT) share distinct hydraulic (flow zone indicator, FZI) characteristics. These identify intervals with lower potential issues. results imply fines migration due erosion one key processes must be understood controlled order mitigate area. Future investigation should include numerical damage, including water–rock interaction tests, critical flow velocity measurements, analysis under reservoir conditions.