Analytical and Numerical Solutions of Radially Symmetric Aquifer Thermal Energy Storage Problems

Abstract

Abstract. The paper discusses analytical and numerical radial solutions of the differential equations for heat transport in water-saturated porous media. In particular, a similarity solution is obtained for a 2D-horizontal confined aquifer with constant radial flow. Numerical solutions are derived using a high-resolution Lagrangian approach suppressing spurious oscillations and artificial dispersion. There is a good correspondence between numerical and analytical solutions.The primary purpose of the investigation has been to calculate the recovery factor of an Aquifer Thermal Energy Storage 5 (ATES) system with a cyclic repetition of injection and pumping. Solutions covering both instantaneous and delayed heat transfer between fluid and solid, as well as time varying water flow, are derived and applied to a one-well test case.In hydrological terms, these solutions are relevant for a wide range of problems where groundwater reservoirs are utilized for extraction and storage (viz. irrigation; water supply; geothermal extraction).

A Novel Spacetime Boundary-Type Meshless Method for Estimating Aquifer Hydraulic Properties Using Pumping Tests

“…The pumping tests usually involve pumping from a single well and the groundwater heads are measured at the pumping well and observation wells over time. The curve-matching analysis, such as the log-log curve matching method, is usually adopted for estimating hydraulic properties [6,7,9]. However, the curve-matching procedure requires matching two graphical plots by hand or using commercially available computer programs [10,11].…”

“…The groundwater flow to an extraction well is axisymmetric [4][5][6], which refers to flow that is symmetric with respect to a central axis. Axisymmetric conditions are therefore suitable for modeling the aquifer tests because the impact of stresses on the groundwater system is radially symmetric [7][8][9]. The Theis solution has commonly been applied to analyze problems involving transient flow to a well, which assumes radial flow to a well of constant discharge in an infinite aquifer [10,11].…”