The engineering challenges of CO2 storage

The permanent underground storage of large quantities of anthropogenic carbon dioxide from thermal energy and industrial plant is widely recognised as a fundamental tool which can help to avoid the worst impacts of climate change. To achieve this effectiveness, it will require widespread global deployment in a new industry which would rival the current oil and gas industry in its scale and ambition. Many of the technologies for carbon dioxide storage are the adaptations of oil and gas technology, but there are some important differences. These arise from: 1. the thermodynamic properties of carbon dioxide, 2. the essential requirement for long-term storage site integrity, 3. the absence of an established and mature business model for the industry and 4. the contrasting regulatory environments between carbon capture and storage and oil and gas extraction. Whilst the underground injection of carbon dioxide can truly be considered a proven technology, there are a range of engineering challenges to achieve this in a safe and cost effective manner. This paper sets out to explore some of these challenges and concludes with a view of what next steps are required to progress carbon dioxide storage effectively within the UK. The challenges of injecting carbon dioxide into offshore subsurface reservoirs: Arrival processing (heating before injection) Injectivity assessment - how many wells? Platform or subsea? Well design for long service operations and monitoring The challenges of forecasting reservoir and injection performance within porous and permeable storage reservoirs: Issues influencing carbon dioxide storage capacity Assuring storage site containment integrity Geology and engineering - uncertainty and risk Where has the industry got to and what are the practical next steps?