Polytopal nodal discretisation of mixed dimensional poro-mechanical models in geological media, application to fault reactivation and induced seismicity (Roland Masson)

02.06.2026 14:00 – 15:00

Subsurface resources—such as deep geothermal energy, underground hydrogen storage, and geological CO₂ sequestration—are key pillars of the energy transition and sustainable development. However, fluid injection and extraction alter the pressure and stress state of the surrounding rock, potentially triggering fault reactivation and induced seismicity. Predicting and mitigating these risks is therefore essential for the safe and sustainable use of the subsurface.

In this context, numerical simulation provides a powerful framework for understanding, predicting, and managing such coupled processes. The proposed model integrates Darcian fluid flow in both the porous matrix and fault network, poroelastic deformation of the surrounding rock, and frictional contact along faults. A key feature is the incorporation of dynamic friction governed by rate-and-state laws, in which the friction coefficient depends on slip velocity and an evolving state variable.

We present a polytopal discretization approach for simulating these coupled processes, explicitly accounting for fault networks and rate-and-state friction behavior. The contact mechanics formulation relies on a mixed approach combining the Virtual Element Method with bubble stabilization and a face-wise constant approximation of tractions. Time integration is fully implicit, with adaptive time stepping and tailored block preconditioners that exploit the structure of the discrete contact problem. Fluid flow in the mixed-dimensional setting is discretized using a conservative Hybrid Finite Volume scheme, while poromechanical coupling is handled through iterative algorithms.

The methodology is demonstrated on a fault reactivation scenario relevant to CO₂ sequestration, highlighting its capability to capture the interplay between fluid flow, deformation, and fault slip.

Lieu

Conseil Général 7-9, Room 1-05, Séminaire d'analyse numérique

entrée libre