This project is about developing a new tool and test protocols to conduct stress profiling in crystalline rock for a better estimation of stimulation efficiency and induced seismicity related to the creation of subsurface heat exchangers. It is organized into four inter-related work packages aiming to develop instrumentation and test protocols at the laboratory, the intermediate field-laboratory and the geothermal project scales: (1) borehole instrument testing and upgrading at relevant geothermal temperatures and pressures, (2) field-scale demonstration of stress profiling in the highly controlled environments of two major underground research laboratories, SURF (USA) and BULG (Switzerland), (3) laboratory-scale testing of protocols in fully controlled 3D stress regimes, and (4) forward and inverse 3D stress analyses using fully coupled Thermo-Hydro-Mechanical (THM) numerical modeling conducted at different scales.