Exploitation of subsurface resources, including the use for long-term storage of fluids and gases, modifies the state of stress of the formations. This has potentially large effects at the surface and on the existing infrastructures. It also modifies the equilibria within the geological formations.

Typical observable effects are subsidence, which may affect (for offshore fields) the platforms, the shoreline, as well as all the near-coast infrastructures. Whereas for onshore fields, changes in soil gradients may be observed resulting in modified surface drainage patterns, hence the local hydrological conditions. Within reservoirs, strong compactions may change the productivity of wells and their stability. Finally, the stability of faults may be modified, which may produce seismicity and leakage of deep fluids to the surface due to changes in the hydraulic properties of the fractures.

The onset of such problems can be evaluated “a-priori” by using large-scale 3D geomechanical models, that are able to predict the evolution of the stress state and that can be used to mitigate the negative effects. During the lifetime of the fields, 3D geomechanical models are very useful to assess the effectiveness of mitigation schemes, as well as to understand the interplay between the different compartments of a reservoir. In other words, models can give insights on which volumes are being affected by the operations and how their production affects the neighboring compartment).