Thermo-mechanical stress analysis of wellbore integrity in CO2 storage wells: A case study from the Tubåen Formation, Snøhvit Field Norway

Abstract

Ensuring long-term wellbore integrity is a critical challenge in carbon capture and storage (CCS) operations, where mechanical failure at the casing–cement and cement–formation interfaces can create potential leakage pathways. This study presents a fully coupled thermal mechanical Poroelastic finite element analysis (FEA) simulation to evaluate stress redistribution and failure risks in the Tubåen Formation, Snøhvit Field. Previous studies primarily focused on bulk stress distribution while this simulation captured dynamic stress evolution across initial and post-injection phases, providing insight into interface-specific failure mechanisms. Low-temperature CO₂ injections induced localized stresses amplification leading to radial cracking, debonding, and microannulus development. Long-term well integrity is seriously compromised by these mechanisms. The study also integrated the Drucker–Prager plasticity model to identify failures. High-resolution stress distribution maps identified critical failure zones, enabling more accurate predictions of failure initiation. This approach captured transient effects considering long term CO₂ injection projects, providing an understanding about well integrity challenges specifically at the cement interfaces. In addition to improving long-term storage performance and regulatory compliance, the findings support proactive risk mitigation strategies for CCS well designs.