Geomechanical Risk Assessment in Carbon Capture and Storage: Insights from a Gulf of Thailand Case Study

Geomechanics plays a crucial role for any subsurface operation that alters pore pressure and formation temperature. CO₂ injection into deep storage formations inevitably increases pore pressure, which alters the stress state of the surrounding rock. Additionally, since the injected CO₂ is usually cooler than the storage formation, the resulting temperature difference can impact stresses, particularly near the injection well where the temperature gradient is most significant. Depending on the rock’s mechanical properties and the in-situ stress conditions, the changes in pressure and temperature from injection can cause strain and potentially undesirable mechanical changes.

This study underscores the crucial role of geomechanics in ensuring the integrity of CCS sites, through comprehensive modeling and analysis. Utilizing data from a depleted gas field in the Gulf of Thailand, a coupled flow-geomechanics simulation was performed to analyze the effects of CO₂ injection on rock stress states, caprock integrity, fault stability, and reservoir expansion and surface uplift. Additionally, thermal effect was also analyzed. The findings suggest that with careful management of injection parameters, CCS can be conducted safely in the studied region, thereby contributing valuable knowledge to the field of geomechanical risk assessment in carbon storage operations.