The effects of density and viscosity changes on well flow distribution in HT-ATES well screens
Authors: Beernink Stijn , van Lopik Jan , Hartog Niels , Vardon Philip J. , Bloemendal Martin 
Published: February 2023

&lt;p&gt;High Temperature Aquifer Thermal Energy Storage (HT-ATES) allows seasonal storage of large quantities of sustainable heat available in summer, enabling its utilization in winter, hence reducing GHG emissions (Daniilidis et al., 2022; Fleuchaus et al., 2018; Sheldon et al., 2021). The feasibility and potential of HT-ATES systems is determined by its recovery efficiency. When groundwater is stored at 40 to 80 &amp;#176;C higher than the ambient temperature, large differences in both the density and the viscosity of the groundwater are established. It is commonly known that this creates the potential for buoyancy flow of the hot water to the top of the aquifer which may lead to increased energy losses (Hellstr&amp;#246;m et al., 1988; van Lopik et al., 2022; van Lopik et al., 2016). These density and viscosity changes also affect the distribution of flow over the well screen during injection and extraction, potentially impacting the recovery efficiency of HT-ATES wells. However, these effect have never been studied. In this work, TH-simulations are carried out to identify which processes determine the in- and outflow distribution along the well screen and under which conditions this leads to different recovery efficiency of HT-ATES wells, compared to the conventional method of applying a uniform flow distribution along the well screen like is commonly done in ATES simulation studies.&lt;/p&gt;
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&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;
&lt;p&gt;Daniilidis, A., Mindel, J. E., De Oliveira Filho, F., &amp; Guglielmetti, L. (2022). Techno-economic assessment and operational CO2 emissions of High-Temperature Aquifer Thermal Energy Storage (HT-ATES) using demand-driven and subsurface-constrained dimensioning. &lt;em&gt;Energy, 249&lt;/em&gt;, 123682. doi:https://doi.org/10.1016/j.energy.2022.123682&lt;/p&gt;
&lt;p&gt;Fleuchaus, P., Godschalk, B., Stober, I., &amp; Blum, P. (2018). Worldwide application of aquifer thermal energy storage &amp;#8211; A review. &lt;em&gt;Renewable and Sustainable Energy Reviews, 94&lt;/em&gt;, 861-876. doi:10.1016/j.rser.2018.06.057&lt;/p&gt;
&lt;p&gt;Hellstr&amp;#246;m, G., Tsang, C.-F., &amp; Claesson, J. (1988). Buoyancy flow at a two-fluid interface in a porous medium: Analytical studies. &lt;em&gt;Water Resources Research, 24&lt;/em&gt;(4), 493-506. doi:10.1029/WR024i004p00493&lt;/p&gt;
&lt;p&gt;Sheldon, H. A., Wilkins, A., &amp; Green, C. P. (2021). Recovery efficiency in high-temperature aquifer thermal energy storage systems. &lt;em&gt;Geothermics, 96&lt;/em&gt;, 102173. doi:10.1016/j.geothermics.2021.102173&lt;/p&gt;
&lt;p&gt;van Lopik, J. H., Hartog, N., &amp; Schotting, R. J. (2022). Using multiple partially-penetrating wells (MPPWs) to improve the performance of high-temperature ATES systems: Well operation, storage conditions and aquifer heterogeneity. &lt;em&gt;Geothermics, 105&lt;/em&gt;, 102537. doi:https://doi.org/10.1016/j.geothermics.2022.102537&lt;/p&gt;
&lt;p&gt;van Lopik, J. H., Hartog, N., &amp; Zaadnoordijk, W. J. (2016). The use of salinity contrast for density difference compensation to improve the thermal recovery efficiency in high-temperature aquifer thermal energy storage systems. &lt;em&gt;Hydrogeology Journal, 24&lt;/em&gt;(5), 1255-1271. doi:10.1007/s10040-016-1366-2&lt;/p&gt;