Evaluation of Proppant Performance in Maintaining Fracture Conductivity Under Simulated Geothermal Reservoir Conditions

Abstract

The long-term effectiveness of hydraulic fracturing in geothermal and unconventional reservoirs critically depends on the ability of proppants to maintain open flow pathways under in-situ stress and temperature. This study presents a laboratory-based evaluation of proppant performance using a series of flow-through experiments designed to replicate reservoir-relevant conditions, including elevated confining pressures, high temperatures (up to 250 °C), and continuous fluid flow. Fracture conductivity is commonly used as the key parameter traditionally used in field-scale fracture design, so we report it as the primary measurable indicator of how proppants contribute to maintaining fracture conductivity over extended periods of loading. A suite of proppant-packed fracture analogs was constructed and tested to characterize their mechanical and thermal responses during progressive loading. The experiments captured how fracture conductivity evolves as a function of proppant type (resin coated, low density ceramic, pet coke, & Sand), grain strength, thermal stability, and interactions with the surrounding rock or bounding surfaces. Results show that conductivity degradation varies significantly among proppants: some materials retain permeability even under severe thermo-mechanical conditions, whereas others exhibit substantial loss due to embedment, compaction, thermal softening, or grain crushing. The results contribute to improving proppant selection and fracture-design strategies for high-stress, high-temperature reservoirs, where long-term fracture performance is essential for sustained production