Benchmark Test and Sensitivity Analysis for Geothermal Applications in the Netherlands

Abstract

Accurate prediction of temperature and pressure distribution is essential for geothermal reservoir exploitation with cold-water re-injection. Depending on our knowledge about the heterogeneous structure of the subsurface, reservoir development scheme can be optimized, and the overall lifetime of the geothermal field can be extended. In this study, we present Delft Advanced Research Terra Simulator (DARTS) which can provide fast and accurate flow response of the geothermal field. This simulation framework is using the Operator-Based Linearization (OBL) technique and is suitable for uncertainty analysis with a large ensemble of models. In DARTS, we select the molar formulation with pressure and enthalpy as primary variables. In addition, a fully-implicit two-point flux approximation on an unstructured grid is implemented to solve the mass and energy conservation equations. In our work, DARTS is compared with the state-of-the-art simulation frameworks using benchmark tests within synthetic geological models. We demonstrate that our simulator achieved a good match for both low- and high-enthalpy conditions with the maximum spatial difference in pressure and temperature below 2% in comparison to other simulators. At the same time, DARTS provide high performance and flexibility of the code due to OBL approach which makes it particularly useful for uncertainty quantification. We investigated the influence of different geological parameters to the thermal breakthrough time for both low- and high-enthalpy conditions and found that the system lifetime heavily relies on variation in hydrothermal reservoir properties. Afterward, we conducted a series of sensitivity analysis for various production regimes and geological properties in realistic geothermal case studies.