Engineered Geothermal System (EGS) projects have attempted to apply hydraulic, acid and thermal stimulations to improve the transmissivity between wells and create a network of fractures that allows for sustainable extraction of heat stored in the solid rock matrix. So far, this has not been fully designed using engineering principles, partially because hydraulic stimulation models only assume mode I (opening) fracture. Within this project, via laboratory based pilot studies, we will develop procedures for field operators to stimulate Mode II (shear) and Mode III (out-of-plane shear) fractures, to engineer topologically complex 3-D set of fractures typical in EGS reservoir in such a manner that heat exchange area is maximized, reservoir impedance is minimized and finally micro-seismic events are limited.
