| Abstract |
For sustainable geothermal energy management, fluid reinjection’s coupled physicochemical impacts on reservoir properties must be understood. Our study focuses on the Menderes Massif in Türkiye, investigating how reinjection affects reservoir integrity with fluids of varied temperature and pCO₂. In fracture-controlled geothermal systems, long-term viability hinges on fracture density, connectivity, porosity–permeability, and hydrothermal sealing; pinpointing how these traits evolve under different reinjection regimes is therefore critical to sustaining output. Micro-CT and thin-section imaging have resolved the reservoir’s initial fracture geometry, porosity, and connectivity, and preliminary analyses reveal that, despite the marble-centric focus of earlier studies, schist-dominated zones possess higher porosity, while pervasive tectonic deformation imparts significant secondary permeability to all lithologies. The evolving porosity, mineralogy, and fluid chemistry during reinjection were examined using high-pressure, high-temperature hydrothermal experiments on representative well cores with Menderes Massif fluids. Autoclave runs spanning 25–110 °C and 5-100 bar recreated reinjection conditions, while time-lapse tracking of saturation indices and mineralogical changes, via SEM, XRD, XRF, and key Ca–Mg and dissolved-CO₂ indicators, captured the progressive geochemical adjustments that steer porosity, scaling, and fracture behaviour during each run. Coupling fracture metrics with baseline mineralogy-porosity findings and forthcoming hydrothermal experiments, this study transcends purely numerical forecasts to deliver an evidence-driven view of how reinjection reshapes the Menderes Massif reservoir and guides measures to curb scaling, sustain permeability, understand its impact on micro-seismicity, and ensure long-term productivity. |