Carbon Capture and Storage: Downhole Tubular Materials Selection Challenges and Multidisciplinary Approaches to Mitigate Failures and Adhere to Regulatory Compliance

CCS is the process of injecting CO2 captured from an emission source into deep subsurface rock formations for long-term storage. CO2 is captured from flue gas produced by fossil-fueled power plants or industrial facilities, typically compressed to convert it from a gaseous state to a supercritical fluid, and transported to the sequestration site, by pipeline. The CO2 is then injected into a deep subsurface rock formation through a Class VI well, using technologies that have been developed throughout decades of experience in oil and gas recovery and storage. When injected in an appropriate receiving formation, CO2 is sequestered by a combination of physical and geochemical trapping processes.

CO₂ sequestration associated with the offtake from non-traditional sources like fossil-fueled power plants or industrial facilities is more complicated than originally thought. The CO₂ stream will contain non-hydrocarbon contaminants that can increase the corrosivity of the injectate and will change dramatically the in-situ reservoir fluids. These risks heighten concerns that a downhole tubular failure could lead to the contamination of underground sources of drinking water (USDWs) in an upper formation. Additionally, regulations in the United States also require well monitoring and integrity for 50 years after abandonment.

The authors have been tasked with the challenge of designing injection and monitoring wells by several operators. Downhole tubular design from an operational loading perspective always carries some challenges, however the most critical challenge faced by this industry is the materials of construction from a corrosion perspective.

Over the years the authors, have developed a multidisciplinary approach on how to tackle these challenges as well as innovative ways of testing materials and performing thermohydraulic and thermodynamic analysis techniques to determine the operational and environmental conditions of these wells that help determine the best fit for purpose materials of construction. Some of these aspects will be presented.