The probably best-known examples of rock mechanical effects on reservoir scale behaviour are reservoir compaction and associated surface subsidence. Operational problems related to subsidence are environmental concerns, like risk of flooding in land operations, or platform safety concerns in offshore production. A majority of compaction-induced problems are associated with casing collapse within or adjacent to the compacting reservoir. It is on the other hand well established that compaction may be a prominent drive mechanism in relatively soft oil reservoirs.

Pore pressure depletion leads to changes in Earth stresses not only in effective stress, but also in the total stresses. These stress changes control not only compaction and subsidence, but may also lead to changes in the fluid flow performance of the reservoir. Permeability may change, and the directions of preferred flow may be altered. In some cases, the stress changes within and near the reservoir triggers seismicity during reservoir depletion. This dynamic nature of petroleum reservoirs also affects the stability of wells to be drilled and produced during the lifetime of the reservoir. Last but not least, geomechanical alteration of the reservoir and its surroundings may be observed in time-lapse (4D) seismic surveys. Reservoir geomechanics is thus becoming an increasingly important part of reservoir management.