During carbon sequestration, wellbore cement could be vulnerable to high pressure and temperature in underground storage settings.Deterioration has been observed under supercritical CO2 exposure condition in previous experimental and field studies.Previous studies also showed that a reduction in compressive strength when cement prisms were exposed to supercritical CO2 when compared to the ones exposed to control.In this study, cement prisms were subjected to various exposure conditions to decouple the effects of high temperature (up to 85 ℃);high pressure (up to 28.9 MPa);and CO2 injection.Modulus of rupture and compressive strengths of the cement prisms were tested and evaluated.The results indicated the cement prisms had a lower compressive strength when cured at high temperature and in synthetic Mt.Simon brine solutions.Furthermore, a lower modulus of rupture was observed when cement prisms were exposed to high pressure and supercritical CO2.Alteration of the cement paste was identified and quantified by using scanning electron microscopy.