EP10 - Numerical THMC-Modelling


Aims

The long-term behavior of georeservoirs and specifically the behavior of the Thuringian Basin are the foci of this project. The central question to be answered is: what do the deep and near-surface fluid dynamics of this large volume reservoir look like? Are there exchanges between thermally-driven, deep fluid convection and near-surface groundwater flows? Such exchanges could explain the occurrence of near-surface, salty groundwater in the Thuringian Basin.

Working area

The simulation model comprises the entire Thuringian Basin.

Methods

The simulation model of the Thuringian Basin is based on the 3D overview model by the Thuringian Office of Environment and Geology (TLUG). The 3D overview model comprises 12 stratigraphic units and 54 fault zones. TLUG gave the model to EP10 in the form of a structured mesh.

The finite element simulation places certain demands on the quality of the elements in the mesh. The elements particularly in the fault zones and the outcropping stratigraphic layers were not able to meet these demands. Because of this, a thorough reconstruction of the computational grid was necessary.

In subproject 10.1, a workflow was developed to convert the structured mesh of the 3D overview model into a geometric model/mesh that is suitable for the finite element simulation. Together with TLUG and other INFLUINS subprojects, simulations of the geometric model with diverse material parameters and boundary conditions as well as varying parameterization are planned for the remainder of the project duration.

Results

The first successful prototype of a simulation model passed testing in July 2014. The integrated fault zones in this model have equipped with a very low coefficient of conductivity at 10^{-11} m/s. At the southwestern and northeastern edges of the simulation area, hydraulic head boundary conditions were set. The simulation results met the expectations.

TM-Modell-01-Results-02-scaled

Ergebnisse Testmodell: Verwerfungen (grün dargestellt), Äquipotentialflächen des hydraulischen Drucks eingefärbt entsprechend der stratigraphischen Schicht, Stromlinien des Grundwassers eingefärbt entsprechend der Geschwindigkeit (Quelle: Thomas Fischer, Department Umweltinformatik, Helmholtz Zentrum für Umweltforschung)


With this simulation model comes the opportunity to test other subprojects through similar parameterization as well as to continue to improve the existing model.

Team

Members of the Team EP10 you will find here.