Speaker: Bérénice Vallier

Date: Thursday 5th of February 2026, 10am

Abstract:

Numerous numerical models have been developed to study natural hydrothermal circulation and its interaction with industrial processes in various geothermal contexts. The main part of this presentation numerically studies deep circulation in the Upper Rhine Graben (URG) to investigate the origin of the thermal anomaly and the impact of fluid injection on induced seismicity. First, a thermo-hydro-mechanical (THM) model is developed to provide new insights into hydrothermal convection. Secondly, a numerical study based on the diffusion of overpressures from fluid injection is conducted to determine an appropriate pumping strategy that will reduce the risk of induced seismicity. Fluid injection with an oscillating flow rate is an alternative that has the potential to significantly reduce induced seismicity on distant faults while enhancing permeability in the near-well region. Drawing on my knowledge of geomodelling and deep circulation in the URG, I have conducted a preliminary study on fluid natural circulation in the Taupō Volcanic Zone (TVZ, New Zealand). This study aims to investigate the impact of rock anisotropy on flow paths for deep geothermal fluids in fractured, highly metamorphic volcanic reservoirs in the TVZ. This preliminary study demonstrates that permeability anisotropy significantly alters fluid flow in the crust, favouring vertical flow but reducing its intensity. In future, the thermo-hydro-mechanical and chemical effects will be studied in the TVZ. Understanding these processes is crucial for identifying the mechanisms that control the opening or sealing of fractures through hydrothermal circulation in TVZ geothermal reservoirs.