Models of flow and mixing of CO2 and brines in heterogeneous porous media

Sub-surface carbon storage, which involves separation of CO2 from power station fuels or waste gases and injection and storage of the CO2 underground, offers one of the more economical and practical methods for society to manage its transition to a low-carbon economy. A key aspect of sub-surface carbon storage is the need to ensure that the storage is safe and efficient and this requires the ability to model the fate of the CO2 over the ~ 10000 year storage period. Key mechanisms which will increase the security of CO2 storage are residual trapping, where some CO2 is retained in pore space by surface tension, and solubility trapping in which CO2 dissolves in formation brines. The rate at which both these mechanisms will operate will be strongly controlled by the small and medium scale (10 cm to 100's m) heterogeneities in permeability of the reservoirs.

The project will examine the impact of the characteristic heterogeneities in sedimentary units on the rates of residual and solubility trapping. The project will use a combination of approaches. Laboratory experiments and theoretical analysis for miscible currents with large viscosity differences may be used to understand the flow of brines and CO2 through heterogeneous media characteristic of reservoirs. The project may combine this with field studies of the permeability heterogeneities of sedimentary formations and use this information to predict the important structural heterogeneities of potential CO2 reservoirs.

The student will become familiar with the processes and requirements for geological carbon storage. They will join a group of more than 10 (faculty, post-docs and students) working on a whole range of problems related to CO2 storage. The student will be encouraged to interact with this group who are carrying out related research on a variety of issues in carbon storage including modelling of multi-phase flow, seismic imaging of reservoirs and studying the fluid-fluid and fluid-mineral reactions within reservoirs. While the modelling will be based on the field examples, the theoretical and experimental tools developed will be generic and applicable to a wide range of heterogeneous media.