Project Overview
Approved for funding through ACT 3: Accelerating CCS Technologies Round 3 international partnership in 2021, Carbon Management Canada focused on enabling long-term CO2 storage in depleted oil and gas reservoirs. By completion in 2024, the RETURN project increased the understanding of CO2 injection strategies in depleted oil and gas reservoirs by developing tools that can more accurately simulate the complex processes happening both in the wellbore and the reservoir.
Enabling Future Large-Scale Emissions Reductions by Unlocking Depleted Fields for CO2 Storage
The RETURN project is part of a larger international initiative with partners from Norway, the Netherlands, Germany, the UK, Italy, and Canada, aimed at improving the understanding, modelling, and monitoring of CO2 injection in depleted hydrocarbon reservoirs — currently underutilized in Alberta’s regulatory landscape. Carbon Management Canada focused on coupled well-reservoir flow modelling, alongside EBN (Energie Beheer Nederland, State Energy Company of the Netherlands), Spectrum H2, and Harbour Energy UK.
Currently, most CO2 storage projects in Alberta target deep saline aquifers. However, there is significant additional storage space in depleted hydrocarbon reservoirs that are not part of the regulation, which provide vast, well-understood storage capacity, and could ultimately provide for a lower cost, managed risk alternative to storage in new saline aquifers. Reusing depleted fields offers significant benefits in accelerating rapid decarbonization, including reduced development time, lower costs, leveraging existing transmission and distribution infrastructure, and decreased uncertainty.
The project focused on unlocking the potential and strategies for injecting cold CO2 in depleted oil and gas reservoirs. This will ultimately enable safe and cost-efficient re-use of depleted reservoirs for long-term CO2 storage. The targeted research required to reach this goal was addressed in: (i) coupled well-reservoir flow modelling, (ii) near wellbore processes, and (iii) wellbore integrity. Experiments, numerical modelling, and field tests focused on understanding how CO2 flows down the well and into the depleted reservoir and identifying safe operational windows for the near-well region and wellbores.
Foundation for Future Cost-effective, Safe and Efficient CO₂ Storage
The project developed and validated a high-resolution coupled wellbore–reservoir simulator (CALYSTO), which accurately models Joule-Thomson cooling, CO2 phase changes, and thermal stresses during injection. The CALYSTO simulator, tested against real-world injection data, offers operational insights that enhance injection efficiency and maintain wellbore integrity. Field experiments confirmed the tool’s accuracy, supporting optimal injection at approximately 300 kg/day without heating CO2, thereby reducing energy demand and costs. Although direct CO2 injection at the CMC Field Research Station (FRS) is modest (~1.5 tonnes/month), RETURN facilitates future large-scale emissions reductions by unlocking depleted fields for CO2 storage.
Advances were made in understanding coupled wellbore-reservoir interaction during non-isothermal CO2 injection into depleted reservoirs and under-pressured saline aquifers. Operational and monitoring data from the CMC Field Research Station were important in realizing this objective. As a result, this software will be able to be used for large-scale CO2 injection into depleted reservoirs, helping to design injection scenarios that avoid injection risks such as Joule-Thomson cooling and the development of hydrates in the reservoir near the injection well. In Alberta, these benefits will be realized when large-scale injection and storage are permitted. These outcomes form the technical and operational foundation for future cost-effective, safe and efficient CO2 storage in Alberta and internationally. A final report was produced, integrating all work packages of the consortium.
What’s next?
The experience gained and tools developed during the project will enable CMC to help industries with planning to permanently store CO2 in depleted hydrocarbon reservoir projects. The Computer Modelling Group Ltd (CMG) has reached out to pursue a collaboration on integrating the outcomes of geophysical monitoring into reservoir simulation and to improve their historical matching capabilities by utilizing the extensive injection dataset from the CMC FRS.
Outcomes of the ENSURE project provide policy-relevant evidence to consider including depleted hydrocarbon fields in CCS regulations, potentially enabling policy change. RETURN provides a pathway to include depleted hydrocarbon reservoirs in Alberta’s formal CO2 storage regulations—unlocking vast underutilized capacity. Demonstrating the safety and predictability of CO2 injection into depleted reservoirs boosts confidence and de-risks broader deployment.
Notably, the project disseminated learnings through various conferences and publications, such as Enhancing Geological Carbon Storage: A Detailed Study of CO2 Wellbore and Reservoir Interactions: 17th International Conference on Greenhouse Gas Control Technologies, October 21-24, Calgary, Alberta, Available at SSRN 5071245.
ERA’s Partnership Intake Program provided continued funding to further advance the development of cost-effective storage and monitoring protocols:
Integrating the outcomes of geophysical monitoring into reservoir simulation will continue during the follow-on ERA project, Advanced Multi-Physics Sparse Monitoring (AMPS), referred to by Alberta Innovates. The AMPS project aims to develop a real-time, semi-continuous, cost-effective, and sustainable surveillance system for CO2 storage.