Experimental studies on corrosion of cement in CO2 injection wells under supercritical conditions

• Cement corrosion experiments were conducted in supercritical CO2.
• The experimental conditions were both static and dynamic situations.
• The temperature and curing time have great effects on degree of corrosion.
• The main corrosion mechanism of CO2 to cement was proposed.

The corrosion performance of cement exposed to supercritical CO2 environments has been investigated under static and dynamic conditions by SEM, EDS, XRD and physical analysis. The dissimilarity of attack was compared in two exposure conditions i.e. gaseous CO2 and liquid CO2 by measuring compressive strength, permeability and penetration depth. The corrosion degree becomes more severe with increasing temperature and exposure time in both phase states of CO2. Experimental results were comparable in magnitude of change to the field observations. The corrosion mechanism and kinetics have been discussed to evaluate corrosion behavior of the cement.