A review of oil well cement alteration in CO2-rich environments

The purpose of this study is to examine previous works undertaken that characterise the cement alteration due to its exposure to CO2-bearing fluids attacking on the interfaces of cement-rock and cement-casing, or through cement cracks, and the cement matrix itself. Numerous studies have reported carbonation of well cements. The majority of studies reported self-healing behaviour of cements cracks observed under general CO2 storage conditions. In addition, defective cement matrix and bonding between cement and casing were also found to be potential causes for leakage pathways. Albeit, severe conditions, such as high acidity degree of brine and high flow velocity, may negatively affect the self-healing behaviour of the cement.