Thermal-hydraulic performance of high temperature aquifer thermal energy storage within naturally fractured reservoir: Functional dependence of heat recovery efficiency to multi-parameters

Abstract

High Temperature-Aquifer Thermal Energy Storage (HT-ATES) systems provide an efficient solution for large-scale energy storage, playing a crucial role in achieving carbon neutrality and reducing peak carbon dioxide emissions. Although naturally fractured reservoirs are abundant in geothermal-rich sedimentary basins, they have been largely underutilized as potential reservoirs for HT-ATES applications due to their complex characteristics. In this study, a multi-physics model was developed to systematically investigate the thermal-hydraulic behavior of HT-ATES in naturally fractured reservoirs. The model was validated against experimental data, showing excellent agreement with production temperatures, with deviations within 3.2 %. By varying key operational parameters and matrix properties, this study quantified their impact on the thermal behavior and heat recovery efficiency of the HT-ATES system. Results showed that injection temperature was the most influential factor on heat recovery efficiency, followed by vertical and horizontal permeability of the reservoir. A functional dependence of heat recovery efficiency on these operational parameters and matrix properties was established and validated, with a relative error of less than 5 % for additional testing cases. Notably, among the simulated cases, naturally fractured reservoirs demonstrated lower heat recovery efficiency but higher total energy recovery potential due to their enhanced fluid accommodation capabilities. This work provides a deep understanding of the performance dynamics of HT-ATES systems in naturally fractured reservoirs, offering critical insights for operational strategies optimization.