KWR researcher Jan van Lopik successfully defended his doctorate dissertation entitled: ‘Design of infiltration and abstraction well systems in heterogeneous groundwater packages’ at Utrecht University on 20 January. His research focuses in particular on optimising the design of wells with the aim of enhancing the efficiency of underground applications such as dewatering and high-temperature heat storage. This can save both energy and costs. The research promotor was Professor Ruud Schotting of the Environmental Hydrogeology group and the co-promotors were Dr. Amir Raoof (UU) and KWR colleague Dr. Niels Hartog.
Flow behaviour in partially-penetrating wells
Maximising pumping efficiency depends crucially on a minimal influence on the hydraulic field during re-injection. Fast High Volume Infiltration (FHVI) wells are increasingly being used for this purpose: partially-penetrating filters with a very limited filter length. In his research, KWR researcher Jan van Lopik compared the flow behaviour around an FHVI well with that around a fully-penetrating well in the same aquifer. He conducted extensive field trials (including the injection of both bromide and heat tracers) and model simulations. In addition, the influence of the nonlinear flow in wells of this kind was mapped out on the basis of column experiments. The flow velocity of groundwater means that turbulent flow is a possibility and Darcy’s law is therefore not applicable.
Optimisation of recovery efficiency
The research also included an investigation of whether multiple partially-penetrating infiltration and extraction filters in a single borehole can improve the recovery efficiency of thermal energy in high temperature storage systems. Numerical simulations in the SEAWAT code for MODFLOW were used to investigate the possibility of preventing the density-driven flow of the infiltrated hot water in this situation. The research showed that major gains in recovery efficiency can be achieved if the well system is designed on the basis of an accurate description of the variability in the vertical permeability of the soil.