Some Aspects of Caprock Failure in Geo-sequestration of Carbon Dioxide: a Review

The Industrial Revolution has led to a substantial i ncrease in the generation and release of greenhouse gases (GHG) into environment. These GHGs like CO2 if present in abundance in the atmosphere cause damage to the natural ecosystems through global warming. One of the possible approaches to mitigate the global warming phenomena is by safely and long-term underground disposal of CO2 in suitable geological formations. The sealing capacity of the caprock should be capable to prevent the stored CO2 from escaping or causing other undesirable circumstances for a successful geosequestration project. This paper examines the change in the permeability and strength behaviour of the sedimentary rocks with under different stress conditions during and after the injection of CO2 with regard to the factors that can potentially hamper the caprock’s integrity and lead to possible of escaping of CO2 from the reservoir. In addition, the consequences of any sort of leakage, the mechanisms of failure of the cap-rock and migration of the CO2 through the fractured rock mass are als o discussed. The geo-mechanical effects of CO2 storage on cap rock properties and behaviour are analysed further with emphasis on crack initiation and propagation along with the factors responsible for it.