Impact of Wellbore Lateral Heat Transfer on the Performance of High-Temperature Aquifer Thermal Energy Storage System

Summary This study investigates the impact of wellbore lateral heat transfer — often overlooked in prior research — on the performance of high-temperature aquifer thermal energy storage (HT-ATES) systems. First, we implemented a fully coupled in-house wellbore simulator (MOSKIO) integrated with a reservoir simulator (PorousFlow) under the framework of MOOSE, comparing the numerical and analytical modeling approaches, and the approach without considering wellbore lateral heat transfer for assessing wellbore lateral heat transfer in a 3D multi-layer HT-ATES system with five-wellbore. Second, we studied the impacts of different wellbore configurations, reservoir properties and operational parameters on the HT-ATES performance. The analysis focused on performance indicators such as energy recovery efficiency, extracted energy, wellbore lateral heat loss fraction and reservoir heat loss fraction. The typical maximum wellbore lateral heat loss fraction, calculated using the analytical approach, is about ∼6%, slightly lower than that from the numerical approach, 7%, due to static temperature assumptions in the far-field formation. While the analytical approach offers slightly faster estimations for preliminary assessments, the numerical approach remains essential for capturing complex thermal interactions and providing precise long-term performance predictions. Smaller wellbore diameters (e.g., 6.75 inches) improve energy recovery efficiency but yield higher well pressure drops. The number of supporting wells significantly influences HT-ATES performance, with 2∼3 supporting wells providing better energy recovery efficiency and reduced heat loss. Lower conductivity casing materials (e.g., 0.045 W•m−1•K−1) significantly mitigate heat loss, while proper inter-well distances balance thermal breakthrough, system performance and operational constraints. Higher flow rates (e.g., 25 L•s−1) and elevated injection fluid temperatures (e.g., 210°C) also enhance energy recovery and reduce heat losses. Longer storage durations (e.g., nine months) initially distribute heat within the aquifer but may decrease energy recovery efficiency over time. This study highlights the critical role of wellbore lateral heat loss in evaluating the performance of the HT-ATES system, offering insights for more effective thermal energy management. Impact of wellbore lateral heat transfer on the performance of high-temperature aquifer thermal energy storage system