One perceived advantage for the use O&G fields for first generation CO2 storage is the potential reduction in costs for CO2 transport and storage by re-using existing O&G facilities, especially offshore. This report aims to review the potential re-use of the related infrastructure and assess the suitability of certain infrastructure for re-use.
The decommissioning of large-scale O&G infrastructure associated with depleted fields in some regions of the world is approaching and is already occurring in the North Sea. This means it is important to understand the potential for re-using existing infrastructure for CO2 storage, prior to scheduled decommissioning in the near future. Not only might this option be cost-effective for early deployment of intermediate scale CO2 storage (enabling long term infrastructure of CCS in the future), the re-use of existing O&G infrastructure could also potentially defer decommissioning costs.
This report includes 5 case studies in the North and Irish Seas (Camelot, Atlantic & Cromarty, Hamilton, Goldeneye and Beatrice) and a re-usability index was developed to indicate the potential each element of restructure had for re-use.
The study concluded that the key attributes determining whether any item of infrastructure could be re-used are integrity and life extension options. In general, all elements of infrastructure have the potential to be re-used for CO2 operations. However, all specific cases need to be evaluated on a project by project basis. Additional generic studies about the potential for re-use are unlikely to add significant new knowledge to the sector.
- An infrastructure reusability index has been developed for the purpose of this study and applied to 5 case studies in the North and Irish Seas (Camelot, Atlantic & Cromarty, Hamilton, Goldeneye and Beatrice).
- It is not feasible to define a generic functional specification for re-use of a depleted oil or gas field because its suitability depends on the specific requirements of the project such as longevity, CO2 injection rate, CO2 phase and capacity.
- The production strategy used on oil or gas reservoirs influences their suitability for storing CO2.
- Elements of O&G infrastructure have potential to be re-used for CO2 but must be evaluated on a case by case basis.
- Suitability for re-use depends primarily on the characteristics of the intended CO2 supply to the store.
- Integrity and life extension options are key attributes of suitability for re-use.
- O&G derived practices, processes and tests exist to assess suitability of existing infrastructure for re-use.
- From an infrastructure perspective, the primary functional specification is one of sufficiency. The equipment must have a pressure rating and material specification sufficient for the proposed project, the remaining longevity must be sufficient, and, if a platform is required, the installation must have sufficient space, power and weight bearing capability.
- Recommendations for further work include examining options for extending the life of infrastructure assets and considering regulatory processes in other regions.