Grants and Contributions:

Grant or Award spanning more than one fiscal year. (2017-2018 to 2022-2023)

Greenhouse gas emissions and their accumulation in the atmosphere represent a major environmental concern for global warming. Assessments reported by the Intergovernmental Panel on Climate Change (IPCC) conclude that underground storage of carbon dioxide could play a significant role in mitigating climate change. A variety of different industrial scale CO 2 storage projects provide strong empirical support that CO 2 storage can be implemented safely. Nevertheless, significant uncertainties remain regarding underground storage of large volumes of CO 2 at the scale necessary for this technology to play a significant role in managing global emissions.

One of the main critical issues for geological storage is to ensure stored CO 2 does not escape (or leak) from underground formations. As a conceptual framework for assessing storage security, we adopt the view that the only risk of leakage arises from mobile free-phase CO2, which is not immobilized by residual gas trapping, dissolution in the reservoir fluids or subsequent geochemical reactions. Previously we showed that the dissolution of CO 2 in aquifers can be dramatically accelerated by pumping brine within the reservoir in-situ, enhancing its contact with stored CO 2 . Recently, we proposed a new methodology aiming to dissolve CO 2 before it is injected underground (ex-situ dissolution). In that case, the generation of CO 2 droplets small enough to achieve rapid dissolution relies on turbulent two-phase flow within the surface pipeline. We developed a mathematical model for this process and investigated how the rates of dissolution depended on pipeline parameters, flow rates of CO 2 and brine to optimize the process, and we showed it is possible to dissolve all CO 2 within a few kilometers of surface pipelines. That study was supported by an NSERC discovery grant. The main objective of this proposed research is to continue study of the approaches listed above, moving from conceptual stages towards more practical ones.

There are three parts planned: i) coupling the ex-situ dissolution process with the injection process as well as post injection underground reservoir processes; ii) determining the feasibility of scaling up to large injection volumes, which requires systematic study of different scenarios including multi-well injection, well placement, and pressure management; iii) identifying additional worldwide storage capacity using developed methods. Anticipated significance of this research is the development of new methods which reduce the risks of CO 2 storage and help to expand the number and the geographic extent of reservoirs acceptable for storage.