Deployment of Self-Healing CO2 Resistant Cement for Carbon Capture and Storage Wells in Eastern Australia

Abstract

Carbon capture and storage (CCS) is a vital technology in the fight against climate change. Eastern Australia is an important site for CCS activities where one of the operators is starting a CCS project with target to store 1.7 million metric tons (MMT) of CO2 per year, ensuring enhanced safety and permanence in the same reservoirs that have securely held oil and gas for millions of years. This paper explores the benefits of deploying novel cementing technology in CCS wells in Eastern Australia. CO2 injection leads to a corrosive environment, which can cause cement sheath degradation. This paper presents the decision-making process used in selecting a suitable cementing system for the CO2-rich environment post-injection, and the first-time application of a self-healing and CO2-resistant cementing system in Australia. The operator is committed to safer operations throughout the life of the well by providing long-term well integrity for the CCS wells. The failure of cement sheaths due to the degradation of conventional Portland cement in a CO2 corrosive environment can lead to significant environmental risks. The newly developed, self-healing CO2-resistant cement can withstand the effects of carbonation, making it superior compared to conventional cement systems in a CO2 environment. The deployment of this self-healing CO2-resistant cement system technology for the CCS wells in Eastern Australia has the potential to significantly improve wellbore integrity. This technology offers several benefits, including improved resistance to mechanical stresses and vibrations, resistance to chemical attack, and low permeability. In case of loss of the integrity, when the cement sheath is exposed to CO2 leaking fluids, it has the capability to self-heal and restore the long-term well integrity. Several crucial challenges were addressed for successful delivery, including the remoteness of Eastern Australia, limited accessibility to the location, job frequency, and handling at the third-party uniquely equipped blending facility. All challenges were addressed through rigorous quality control processes developed from extensive laboratory testing and comprehensive blend lifecycle management. Post-job result analysis included running wireline logs to confirm the annular barrier. Cement evaluation logs outcomes were excellent and exceeded expectations. Overall, the deployment of novel self-healing CO2-resistant cement system technology for the CCS wells in Eastern Australia ensures safer, more environmentally responsible CCS operations.