Interpreting Thermal Tracer Data in Carbonate Aquifers: Sensitivity Analysis and Identification of Ranges for Significant Heat Transfer Parameters

With the increasing scarcity of resources and the drive to modernize and optimize conditioning systems, there is a growing interest in using aquifers as an energy source for both heating and cooling. The refinement of parameter ranges and sensitivity analysis enables enhanced modeling precision in heat transfer simulations. This research investigates heat transfer processes in a heterogeneous carbonate aquifer. Experimental data from a cross-flow thermal tracer test conducted at the Zvenigorod test site in 2016 were analyzed to determine the range of parameters. The study utilizes a dual-porosity model to represent the aquifer's properties. Heat transfer modeling is performed using a numerical-analytical approach that solves the filtration problem by superimposing the filtration flow velocities associated with pumping and injection wells (The Teis solution). The heat transfer problem is solved using the finite difference method. Interpretation of the experiment yields the ranges of the sought parameters, which were further refined through tracer tests conducted in 2021 using a doublet scheme at the Zvenigorod test site. Additionally, a sensitivity analysis of the parameters, namely rock block heat capacity (C), water-rock block heat exchange coefficient (λ), block shape correction coefficient (β), and average block power (mb), is conducted to investigate their interdependencies and influence on the modeling results. The obtained results contribute to a more accurate prediction of heat transfer in designing various environmental conditioning systems, water-to-water heat pumps, and other systems utilizing aquifers as a source of thermal energy.