| Title | A Methodology for the Comprehensive Evaluation of the ‘Geothermal Reinjection Potential’ into Siliciclastic Aquifers, Demonstrated in Zala study area, SW Hungary |
|---|---|
| Authors | Ábel Markó, Maren Brehme, Judit Mádl-Sz?nyi |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | The sustainable utilization of thermal water resources necessitates the reinjection of heat-depleted fluids. In siliciclastic aquifers, however, reinjection often presents operational and geological challenges. This study introduces a novel methodology to evaluate the risks and feasibility of reinjection in sedimentary environments. A new parameter, the geothermal reinjection potential, is defined as the probability of successful reinjection from a geological perspective and is proposed to be assessed similarly to geothermal potential during the exploration phase. To quantify this parameter, a dedicated evaluation scheme was developed, accompanied by a structured, multi-scale scientific workflow. This workflow incorporates scale-dependent and problem-specific approaches and methods. The methodology was applied to sedimentary subbasins of the Pannonian Basin to demonstrate its effectiveness. In the Zala study area, regional hydraulic assessments revealed quasi-hydrostatic conditions within shallow Pannonian siliciclastic aquifers. At the reservoir scale, seismic interpretation techniques—including RMS amplitude mapping and interpretation of spectral decomposition colour blends—combined with well-log-based sedimentary facies correlation, revealed heterogeneities on the order of 100 meters within deltaic formations. Simplified hydrogeochemical model set-up developed for predicting mineral precipitation revealed low risk of carbonate and iron-hydroxide precipitation. Based on these findings, reinjection feasibility was confirmed for the -700 m to -1200 m interval in the Barlahida seismic block, and a reinjection potential map was created. This integrated methodology—incorporating risk assessment, probability of success quantification, and spatial reinjection potential mapping—supports improved decision-making and enhances the likelihood of successful reinjection in sedimentary geothermal systems. |