<p>Characterizing fractures through inversion is essential for predicting the long-term thermal performance of enhanced geothermal systems (EGSs). Previous studies often assumed a constant fracture aperture to simplify fracture inversion. However, both experimental and numerical results indicate significant variations in fracture aperture due to complex thermo-hydro-mechanical (THM) coupled processes during heat extraction. Neglecting these variations can overestimate EGS thermal performance. This study introduces a multi-stage inversion framework to capture the dynamic fracture aperture evolution. The framework executes multiple aperture inversions at different times during EGS operation. In each inversion stage, we use Ensemble Smoother with Multiple Data Assimilation method to assimilate tracer data for aperture inversion, and then perform THM modeling to analyze fracture aperture evolution under coupled THM processes and predict thermal performance. We propose a principle to assure smooth transitions between two consecutive inversion stages, that the posterior aperture fields obtained in an inversion stage are used as the prior aperture fields for the following stage, and that the temperature field simulated in the previous inversion stage serves as the initial temperature field for the following stage. Application of the framework to a synthetic field-scale EGS model demonstrates its efficacy in capturing the dynamic evolution of fracture aperture, resulting in more accurate thermal predictions than previous inversion methods assuming constant fracture aperture.</p>