Modelling fluid injection-induced fracture activation, damage growth, seismicity occurrence and connectivity change in naturally fractured rocks

We develop a fully-coupled hydro-mechanical model to simulate fluid injection-induced activation of pre-existing fractures, propagation new damages, development seismic activities, and alteration network connectivity in naturally fractured rocks. The natural fracture system is represented by discrete network. stress strain fields the porous media are solved framework finite element model, which mimics damage evolution rock matrix based on an elasto-brittle failure criterion simulates normal/shear displacement discontinuities non-linear constitutive law. coupled geomechanics flow processes computed honouring essential coupling mechanisms such as pore pressure-induced shear slip poro-elastic response matrix, stress-dependent permeability/storativity both fractures use numerical developed investigate behaviour two cases deeply buried high-pressure injection, one case with density just below percolation threshold other above threshold. observe strong control emergence, seismicity occurrence change mass subject hydraulic stimulation. also highlight effect that tends drive heterogeneous systems during injection. results our research insights obtained have important implications for injection-related geoengineering activities enhanced geothermal extraction hydrocarbon resources.