Finite Element Modal Analysis of Transient Water Flow in Aquifers

Abstract

In this paper a modal superposition method is applied for the numerical modeling of aquifers. The proximity of aquifers to populated regions requires special care in their management to avoid problems that affect the quantity and quality of the water they supply. To contribute to the management of this type of natural resource, we propose a numerical strategy based on modal analysis using the finite element method. This procedure assist water production scenarios, performing the mass balance where water extraction is done through wells, in aquifers that are subject to natural recharge. This mathematical procedure is based on the modal superposition for transient flow in porous media. To evaluate its efficiency, this strategy was compared with the classical finite element method. The advantage of the proposed method resides in the possibility of reusing the properties of the global matrix of the finite element method in transient problems, for different production conditions given by the distributed recharge and by the water extraction rate from the wells, solving the numerical problem with a more efficient use of computational resources. This strategy is useful in studies of uncertainty quantification, history matching and optimization of water production in aquifers, since these types of analysis are resource intensive for the very large number of numerical simulations required for these scenarios.