Anagrafe della ricerca

For several years the scientific community has analyzed the genesis of earthquakes induced by the injection of fluids into the subsoil. However, the recent increase in seismicity caused by exploitation of the subsurface, sometimes followed by major destructive events [29,30], demands for a deeper understanding of the processes and the development of innovative techniques to mitigate the associated seismic risk. Moreover, a safe exploitation of the subsurface is key for the development of green energy sources such as geothermal energy, and to reduce greenhouse gas emissions via long term carbon dioxide storage. The goal of this project is to study the onset of seismicity as the result of fault slip, taking into account multiphysics couplings in complex geometries and applying advanced numerical methods. The solution of quasi-static poroelasticity is used to provide the initial conditions for slip onset and wave propagation simulations. The bricks composing the proposed framework, in Fig. 1, are the expected outcomes of the following work-packages: WP1-- Space discretization of complex geometries with hybrid grids and coupled numerical schemes: • generation of hybrid grids of simplicial and polytopal elements; • coupling of domains of different dimensions resulting from the application of model reduction techniques to multi-scale problems; • discretization with the use of FEM based and polytopal based (VEM) methods on hybrid grids. WP2 – Coupled models for poroelasticity and wave propagation: • mathematical model for poroelasticity in a faulted and fractured domain; • formulation of the frictional contact problem on faults; • mathematical model of elastic waves propagation as a consequence of fault slip. WP3 – Coupled numerical schemes for poroelasticity and wave propagation: • numerical discretization of poroelasticity in faulted domains; • investigation of monolithic/iterative solvers for poroelasticity in the mixed-mixed formulation; • numerical discretization of the elastic waves propagation problem. WP4 – Applications and investigation of realistic scenarios: • definition, implementation and analysis of test cases; • investigation of additional nonlinear constitutive laws. A strong connection is expected among WP1, WP2 and WP3 for the definition of models, interface conditions, numerical and geometrical coupling. Inputs and objectives are defined in an interplay with WP4. The main outcome of the project is a fully coupled model and numerical scheme for the simulation of fault slip due to changes of the underground pressure and the consequent generation and propagation of a seismic wave, to enhance our understanding of the physical processes behind induced seismicity. This encompasses the advancement of the state of art of numerical approximation methods for PDEs and the development of software tools in an integrated framework.