Speaker
Description
Subsurface porous media, specifically porous rocks, are important for groundwater remediation and underground storage of CO₂ and H₂. Fluid displacement, mixing, and transport are controlled by pore-scale features such as pore connectivity and heterogeneity, yet remain challenging to characterize at field-relevant scales [1]. Pore-scale simulations can resolve these processes, but they are computationally prohibitive at larger scales, whereas continuum approaches relying on averaged parameters struggle to capture the full complexity of heterogeneous media or complex flows. Furthermore, experimental approaches have typically focused on either the pore- (µm-mm) or continuum-scale (cm-dm), leaving an important gap in bridging these two scales.
To address this, we performed dynamic X-ray micro-CT imaging on 2.5 cm by 5 cm core samples of sintered glass and Bentheimer sandstone to resolve tracer transport across the full core sample at pore-scale resolution, thereby characterizing the spatial heterogeneity in the flow field. For both samples, the dynamic scans were accomplished at 100 seconds per 3D scan with a voxel size of 20 microns. Sintered glass was chosen as an initial medium due to its high permeability and homogeneous pore structure, before extending the approach to a Bentheimer sandstone sample. To enable an advection-dominated regime and enhance sensitivity to permeability contrasts, a 65 wt% glycerol–tracer mixture was employed to achieve Péclet numbers in the range of 50–80. Dynamic scans were conducted at two flowrates to support future inversion model validation. A dissolved KI solution was injected as a contrast agent to visualize the propagation of the tracer through the sample. Next, calibration experiments at four KI concentrations (5–25 wt%) established a calibration curve between CT grey value and tracer concentration, enabling a quantitative reconstruction of the concentration field through time. Preliminary data show distinct transport behavior between the two samples: a flat uniform front in the sintered glass reflecting its uniform structure, whereas finger-like structures were observed in the Bentheimer sample driven by small-scale permeability contrasts. Finally, the resulting concentration fields are analyzed using pore network models (PNM) and continuum simulations to bridge pore-scale transport behavior and continuum-scale flow parameters.
Future work will include applying the workflow to more complex porous media such as Estaillades/Ketton as well as to viscoelastic and shear-thinning flows. This approach enables more accurate prediction of flow and transport in heterogeneous reservoirs, enabling better remediation, hydrogen and carbon capture strategies.
References
[1] "Mixing, spreading and reaction in heterogeneous media: A brief review," Journal of Contaminant Hydrology, Vols. 120-121, pp. 1-17, 2011.
| References | [1] "Mixing, spreading and reaction in heterogeneous media: A brief review," Journal of Contaminant Hydrology, Vols. 120-121, pp. 1-17, 2011. |
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| Country | Belgium |
| Student Awards | I would like to submit this presentation into the Earth Energy Science (EES) and Capillarity Student Poster Awards. |
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