Study of Caprock Integrity in Geosequestration of Carbon Dioxide.

The Industrial Revolution has led to a substantial increase in the emission of greenhouse gas (GHG) such as carbon dioxide (CO₂) into the atmosphere, exacerbating the global-warming phenomenon. One option to mitigate GHG emission is by capturing and safely storing the CO₂ in suitable deep underground geological formations. This paper provides a literature review on the potential changes in permeability and geomechanical properties of the caprock and sedimentary reservoir rock caused by the injected CO₂ under in situ conditions, highlighting the factors that can potentially hamper the caprock's integrity. A two-dimensional (2D) axisymmetric numerical model of an ideal CO₂ reservoir with 30 years of injection and 70 years of monitoring phase is also presented. The model results suggest that, for the parametric values and reservoir conditions used in the model, the injection pressure leads to an increase in pore pressure, thereby reducing the effective stress in the formation. An induced vertical displacement of less than 3 mm is observed at the caprock-reservoir interface at the end of the 100-year period. The observed relationships between injection pressure, effective stress, and total displacement are also discussed. [ABSTRACT FROM AUTHOR]