Experimental study of the diffusion-controlled acid degradation of Class H Portland cement

► Novel method of measuring degradation kinetics of cement interface. ► Empirical correlation provides corrosion rate data over a range pH and temperature. ► Correlation used to estimate leakage rates, and it is found that the attack in small annuli will be limited to the bottom of the cement plug and will not result in widening of preexisting annular gaps in the wellbore.