4. The Geomechanics of CO2 Sequestration

Lecturer
Lyesse Laloui

Content

The subsurface storage of CO₂ in deep saline aquifers is a process that involves large amounts of CO₂ (generally more than 1 million tons per year) and causes pressure and stress changes over the span of many square kilometers. Due to the need to ensure the safe storage of CO₂ over these large areas, it is important that we have a solid understanding of how these stress changes occur and what their implications are for storage.

This course focuses on provided students with a deeper understanding of the geomechanics of CO₂ storage such that they will understand the importance of a stable caprock and how the injection of CO₂ is likely to influence this stability. Further, the injection of cold CO₂ will be discussed with both the advantages and the added complications that this type of injection brings. Finally, the use of uplift to track CO₂ plume movement and the risks of induced seismicity will be addressed.

The main topics of the course are:

• Cap rock stability
  • Capillary entry pressure
  • Potential for fault slip in cap rock
  • HM impact of CO₂ injection on clay-rich caprock
• Cold CO₂ injection
  • Advantages
  • Thermal strains
• Uplift
  • Importance for confinement
  • Numerical and analytical approaches
• Seismicity
  • Fault detection
  • Significance of wellbore orientation

Importance of basement rock