THM Modelling of a 3 Year Long Hydraulic Test at the Rosemanowes EGS Site, UK
Résumé
Enhancing and creating the permeability of the fractures in a HDR reservoir system have been the main challenge of numerous field studies, but there is still a lot of work toward the understanding of the physical processes involved and in the relationship in between them and occurrence of induced seismicity. It is agreed that the injection of cold fluid in a reservoir located several kilometers deep induces "small" microseisms which reflect both the pressurization of the preexisting joints and the creation of new fractures. Such micro-seismic can be very detrimental to the success of a project when their magnitude is too high. To anticipate the risks associated with this phenomenon, various hypotheses have been raised, focusing on the amount of injection rate, the presence of fractures close to an unstable mechanical system, changes the chemical properties of fluids but also the effect of long-term cooling of the rock. Our main objective is here to investigate the micro-seismic events linked to the long term cooling of the rock to obtain a better understanding of when and where they can occur, so that they can either be avoided or mitigated