Unpropped But Unignored: Optimizing Perforation Strategy and Geothermal Efficiency Through Fracture Conductivity Profiling

Abstract

Unpropped fracture segments—often referred to as arch regions or residual openings—play a critical yet underexplored role in subsurface flow dynamics. While conventional hydraulic fracturing models focus primarily on propped zones, emerging evidence suggests that even low conductivity unpropped regions can significantly influence fluid transport and energy recovery. This study presents a numerical investigation into the impact of unpropped channel conductivity on perforation placement optimization and thermal performance in Enhanced Geothermal Systems (EGS). Using a custom in-house simulator, we model a series of fracture configurations with varying unpropped channel heights and permeability contrasts. Results demonstrate that the presence and geometry of unpropped channels alter flow pathways and temperature evolution at the production well over time. Comparative analysis against homogeneous fracture models reveals substantial deviations in system behavior, underscoring the importance of incorporating conductivity heterogeneity into design and simulation workflows. This work bridges a critical gap in current modeling practices by quantifying the operational significance of unpropped fracture zones. It offers a foundation for more accurate perforating and doublet strategies leading to improved EGS system efficiency, while opening avenues for future integration with real-time monitoring and adaptive control technologies.