Completed 2024 Carbon (CO2) Storage in Residual Oil Zones
This study unlocked new CO2 geological storage opportunities and accelerated the deployment of carbon capture and storage (CCS) technologies in Australia, supporting our transition to net zero by 2050.
CO2 enhanced oil recovery involves the injection of CO2 into a near-depleted oil field or residual oil zone to help produce some of the remaining oil. Some CO2 is produced with the oil and recycled while the remaining volume of CO2 is stored in the reservoir (Figure 1).
Around the globe, CO2-EOR projects have been injecting and storing CO2 for some 6 decades and are currently responsible for achieving much of the world's CO2 storage in geological formations. CO2-EOR projects benefit from geological knowledge of the storage site, use of existing infrastructure, and dedicated financial incentives that can be used to offset the costs of CO2 capture, transport and storage in the early days of CCS deployment. With the appropriate settings, CO2-EOR can result in larger volumes of CO2 injected and stored than is emitted from the life cycle of any additional oil produced. CO2-EOR projects demonstrate the feasibility of large-scale sustained CO2 injection, storage and monitoring, and can pave the way to purely storage-focussed projects in the future.
Figure 1: An illustration of the CO2-enhanced oil recovery process in a near-depleted oil field. CO2 (white dots) is injected into the oil field to help produce some of the remaining oil (green). Some CO2 is produced with the oil and recycled while the remaining CO2 is stored in the reservoir
Residual oil zones occur in geological reservoirs that contain potentially economic oil resources that can be produced through CO2-EOR (Figure 2) and, importantly, could offer large-scale geological storage capacity, with or without EOR. These rocks can occur beneath or near oil fields or in areas with no conventional oil accumulations but their occurrence and potential CO2 storage and oil resources are not yet well understood in Australia. Aside from the primary driver of accelerating CCS deployment, we considered the potential for incremental oil recovery from CO2-EOR projects to contribute towards domestic energy security and liquid hydrocarbon supply for non-energy purposes (materials produced by oil refineries).
Development of ROZ could be economically beneficial, help to address greenhouse gas emissions, and provide increased energy security through the production of new domestic oil resources.
Figure 2: Residual oil zones can offer a large-scale opportunity for CO2 storage, including through CO2-EOR, with potential oil production of the residual oil from the largely water-saturated reservoir
The CO2-Enhanced Oil Recovery (CO2-EOR) in ROZ study aimed to:
As part of the CO2-EOR in ROZ study we:
For more information on other work in the area of carbon capture and storage (CCS), please visit the Carbon capture and storage page.
All data produced by Geoscience Australia, including the data from this study, is publicly available from the Geoscience Australia's publication catalogue and the Exploring for the Future Data Discovery Portal after quality control and assurance has been performed.
General enquiries: 1800 800 173, clientservices@ga.gov.au
Australia's Future Energy Resources project investigated the national potential for new sediment-hosted energy resources, including oil, natural gas and hydrogen, that can support Australia's transition to net zero emissions by 2050.
Tenthorey, E., Taggart, I., Kalinowski, A., McKenna, J (2021)
Tenthorey, E., Kalinowski, A., Seyyedi, M., Jackson, S., Clennell, B (2022)
