5.5 Conclusions

Injection of CO2 in a geological medium results in pore pressure changes, which in turn affects the stress-state. The change in geomechanical conditions may have adverse effects on the stability of the storage reservoir. A good understanding of the elastic properties of the reservoir and overburden, pre-existing faults and fractures and the initial stress state is vital to evaluate the fluid flow and rock mechanical response to pressure changes. Geomechanical coupled flow models integrating the fluid flow and the stress field may be used in many areas of geological CO2 storage. By combining the geomechanical coupled flow simulation results with measured mechanical changes during the injection phase, the key risks that may lead to leakage of injected CO2 could be assessed early. Studies have shown the importance of building a good rock mechanical property model and that the fractures and faults have a significant role in controlling the pressure and saturation distribution.