Challenge:
The reuse of existing producer wells for CO₂ storage is a critical step in advancing carbon capture and storage (CCS) initiatives to support global decarbonization goals. However, assessing well suitability for CO₂ storage in offshore, depleted oil and gas fields introduces unique challenges. Existing wells may face issues related to structural integrity, material compatibility, and containment security, which are essential for long-term CO₂ storage. An effective assessment requires a detailed analysis of factors such as cement integrity, barrier performance, and the presence of components compatible with CO₂ exposure. In this context, the primary challenge is ensuring that existing well conditions align with regulatory standards for safe and effective CO₂ storage.
Solution:
Our team conducted a comprehensive evaluation of the wells in two ageing Australian gas fields, focusing on key risk factors and necessary improvements to meet CCS requirements. This assessment included the following considerations:
- Injection containment: Ensured that any CO₂ injection would remain within designated storage zones, preventing unintended migration.
- Well Structural Integrity: Conducted a stress analysis to confirm the ability of well casings and tubing to withstand CO₂ injection pressures.
- Primary Barrier Envelope Integrity: Evaluated the main barrier systems to verify containment capabilities and mitigate the risk of CO₂ leakage.
- Secondary Barrier Envelope Integrity: Assessed secondary barriers, such as cement seals, for additional security in the event of primary barrier failure.
- Material Compatibility: Analyzed the compatibility of all well components with CO₂ to prevent corrosion and degradation over time.
This rigorous evaluation enabled a clear understanding of which wells required modifications, such as recompletion or additional monitoring, to comply with CCS requirements.
Value Added:
Our approach allowed the team to identify and mitigate potential risks early in the project, enhancing the overall safety and reliability of the wells designated for CO₂ storage. This proactive assessment provided several benefits:
- Improved compliance with international CCS standards, such as ISO 27914, ISO 16530, NORSOK D-010 and regulations [US-EPA].
- Streamlined project timelines by guiding necessary modifications through a validated assessment framework.
- Reduced operational costs through targeted well modifications, avoiding unnecessary recompletions.
- Strengthened project confidence by addressing key well integrity issues and demonstrating ALARP (As Low As Reasonably Practicable) risk levels.
This assessment exemplifies our technical capability and commitment to safe and sustainable CCS solutions, providing valuable insights for future CO₂ storage projects.
