Accelerated degradation method for cement under CO2-rich environment: The LIFTCO2 procedure (leaching induced by forced transport in CO2 fluids)

For emerging applications such as long-term CO2 storage, establishing and maintaining well integrity during the life of the well pose significant challenges. Particularly, well cement will need to be durable under corrosive environments, such as exposure to CO2-rich fluids, over a long period of time from 25 years to 100–1000 years. To model long-term cement durability in such severe environments, accelerated degradation methods must be considered and developed. This study presents experimental equipment and a procedure showing that it is possible to accelerate Portland cement degradation in the presence of CO2 fluids by applying a potential gradient through a set cement sample in a CO2 environment (the LIFTCO2 procedure). The degradation pattern consists of a series of successive fronts penetrating the cement sample: a dissolution front, a carbonation front, and a gel layer. Such degradation is accelerated when increasing the potential gradient, the temperature, and the CO2 concentration in the electrolyte.