Wellbore Interface and Cement Defects in CO2 Geological Storage: A Review

Abstract

The objective of this article is to analyse previous studies conducted on the impact of wellbore interfaces (casing–cement, cement–formation) and cement matrix defects in geological CO₂ storage. In addition, assessment was conducted on the causes of interface and cement defects in a well, followed by a review on the available remediation techniques to solve wellbore interface and cement defects failure. Previous studies have shown that wellbore interface defects play a significant role in ensuring the integrity of geological CO₂ storage. The main findings of previous studies are the creation of zones during carbonation in cement and the mixed minerals of cement and steel during the corrosion process, which could potentially accelerate the corrosion of steel. It is recommended that more experiments be conducted assessing casing, cement and formation as a system in understanding the chemical reaction with CO₂ for long-term storage to predict the reaction rates of cement and steel with CO₂. Furthermore, performing numerical modelling with experimental data further deepens the assessment of carbonation zones in cement and its function as a barrier against continued reaction between CO₂ and cement and the impact of mixed calcium-iron mineral on the steel surface disrupting the creation of a protective film on the steel surface.