(65a) A Holistic Framework to Assess and Characterize Well Integrity to Manage Safety in Subsurface Carbon (CO2) Storage Applications

Ensuring well integrity is crucial to the safety and viability of subsurface Carbon Storage (CS) operations. Well failure poses serious environmental, economic, and social risks, potentially eroding public trust in this innovative decarbonization efforts. The diverse array of wells used for CS—spanning from newly drilled to over 70 years old—presents unique challenges, demanding customized approaches to ensure reliable, secure CO₂ storage. This research seeks to deepen the understanding of well integrity in CS operation. It presents a holistic framework to identify and characterize primary failure modes into chemical, mechanical, thermal, impurity-induced, and operational failures. Chemical failures may involve processes like cement carbonation and sealant degradation, while mechanical issues can include plastic deformation, radial cracking, debonding, and casing collapse. Impurity-induced failures such as casing corrosion and cement degradation, along with operational challenges stemming from early drilling, production phases, and CO₂ injection processes, further compromise well integrity.

A central focus of this study is how geological, design, operational, and environmental factors drive these failures over time, particularly under the extreme conditions of CO₂ storage. It also investigates the impact of CO₂ composition (CO₂ with impurity) and supercritical states in accelerating failure mechanisms, coupled with factors such as high temperature, high pressure, and corrosive environments, which underscore the necessity for region-specific well design and maintenance strategies. This proposed framework assists in identifying and addressing primary failure causes across various well types and storage conditions, aiming to enhance safety and operational longevity in CS. By addressing these key challenges, this study contributes to the advancement of safer, a resilient CS infrastructure essential for long-term CO₂ sequestration.