Monitoring and interpretation of hydrologically induced deformations at the KTB location

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This research project is intended to quantify the relationship between changes in pore pressure and modifications of the fluid state and depressions of the surface induced by a large scale discharge experiment at the KTB site. Deformation of the upper continental crust will be recorded by ASKANIA borehole tiltmeters at five locations. Principal 3D numerical modelling (poro-elastic Finite-Element-Method, FEM) of the poro-elastic behaviour showed, that significant tilt amplitudes, particulary during controlled fluid injection, can be expected. The observed deformations will be investigated regarding the fluid flow behaviour and the induced geodynamic effect and modelled using a coupled hydro-geomechanical finite-element model (ABAQUS). With the numerical model both effects can be quantified: a) the deformation of the upper crust (tilt measurements) and b) the changes of material parameters in the KTB area. The main aim of this proposed project is to improve the knowledge of the coupled geomechanic-hydraulic processes and to quantify important process parameters. Thus, the understanding of processes of fracture dominated changes of the hydrogeological parameters will be enhanced, geomechanic parameter changes and the heterogeneity of the parameter field quantified, and the induced stress field variation explained, which is believed to be mainly responsible for the increase of local seismic activity.