Re-Use of Oil & Gas Facilities for CO₂ Transport and Storage

Publication Overview

Our recent study ‘Case Studies of CO₂ Storage in Depleted Oil and Gas Fields’ (2017-01) concluded that CO₂ storage in depleted fields would not only be viable with potentially lower risk but could also be relatively cost effective, providing important intermediate-scale storage resources. The report highlighted that re-using an O&G fields would be beneficial as “there would likely be cost savings over saline aquifer sites, particularly in the characterisation stages (where there is the advantage of production history and proved hydrocarbon retention to reduce uncertainty in containment and capacity)”.

Publication Summary

• This report aims to improve the general understanding of issues influencing the re-use of existing Oil and Gas (O&G) infrastructure to address the fundamental question: “under what circumstances might it make sense to re-use redundant O&G infrastructure for CO₂ operations”?
• 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 reservoir pressure at the commencement of CO₂ operations, which is determined by 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.