RETURN (REusing depleTed oil and gas fields for CO2 seqUestRatioN)

The RETURN (REusing depleTed oil and gas fields for CO₂ seqUestRatioN) project was an exciting initiative funded through the ACT programme (ACT3 Call) and made up of a consortium of industry operators, R&D providers, technology centres, universities and a hydrogen producer who came together in 2022 with the goal to enable the safe and cost-efficient use of depleted O&G reservoirs for long-term CO₂ storage through the development of novel solutions for overcoming injection challenges. 

To achieve this, work was performed comprising both experiments and numerical modelling, which focussed on understanding how CO₂ flows down the well and into the depleted reservoir – with special emphasis on Joule-Thomson cooling effects, phase transformations, pressure and temperature cycling, associated flow assurance (incl. production chemistry and geochemistry effects) and the impact thereof on wellbores, reservoir rock and sealing formations. The output of the project was advanced numerical models, able to accurately predict the thermo-hydro-mechanical response of the wellbore-reservoir-caprock system to CO₂ injection.

We were asked by our Client, Net Zero Technology Centre (NZTC) to assist them in their contribution towards the project by providing specialist support over a two year period in the following areas:

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• P & T Cycling Experiments
• Define & Develop Use Cases
• Integration of Case Studies and Injection Scenarios
• Recommendations for Optimized Cold CO₂ Injection & Permit Applications
• Knowledge Dissemination & International Collaboration

Iain Martin, CCUS Theme Lead at NZTC said “the working knowledge and expertise Axis brought to the project consortium in reservoir modelling, the near wellbore interactions and well integrity to the challenges of injecting cold CO₂ into depleted reservoirs played a key role in assisting the Net Zero Technology Centre shape the final deliverables and recommendations for the ACT3 Return Project”.

For further details and to read the final report, please visit: return-act.eu – Reusing depleted oil and gas field for CO2 sequestration