A computationally efficient model of a geothermal well for the Thermal Response Test (TRT) during drilling

Thermal modeling of geothermal wells during drilling offers a practical and efficient approach to determine key thermal properties of subsurface formations, thereby facilitating the optimized design of geothermal energy systems. This study presents the development of a numerical model designed to predict the transient temperature distribution within a wellbore during active drilling operations. The model delineates the wellbore system into distinct thermal regions and formulates governing partial differential equations for each, capturing the effects of conduction, convection, internal heat generation, and time-dependent boundary conditions. The model’s capability is validated against the literature and a third-party code, demonstrating average discrepancies of 1.8% and 0.6%, respectively. Parametric simulations were conducted across a range of operational scenarios to evaluate the impact of critical drilling variables. We found that the outlet temperature of the drilling fluid changes by 30% during a 16-fold increase in the ground thermal conductivity and by 40% during a twofold reduction in the flow rate. The findings underscore the applicability of the model for real-time optimization and predictive control in geothermal drilling operations.