4D microvelocimetry reveals multiphase flow field perturbations in porous media

Many environmental and industrial processes depend on how fluids displace each other in porous materials. However, the flow dynamics that govern this process are still poorly understood, hampered by the lack of methods to measure flows in optically opaque, microscopic geometries. We introduce a 4D microvelocimetry method based on high-resolution X-ray computed tomography with fast imaging rates (up to 4 Hz). We use this to measure flow fields during unsteady-state drainage, injecting a viscous fluid into rock and filter samples. This provides experimental insight into the nonequilibrium energy dynamics of this process. We show that fluid displacements convert surface energy into kinetic energy. The latter corresponds to velocity perturbations in the pore-scale flow field behind the invading fluid front, reaching local velocities more than 40 times faster than the constant pump rate. The characteristic length scale of these perturbations exceeds the characteristic pore size by more than an order of magnitude. These flow field observations suggest that nonlocal dynamic effects may be long-ranged even at low capillary numbers, impacting the local viscous-capillary force balance and the representative elementary volume. Furthermore, the velocity perturbations can enhance unsaturated dispersive mixing and colloid transport and yet, are not accounted for in current models. Overall, this work shows that 4D X-ray velocimetry opens the way to solve long-standing fundamental questions regarding flow and transport in porous materials, underlying models of, e.g., groundwater pollution remediation and subsurface storage of CO2 and hydrogen.

Medienart:

E-Artikel

Erscheinungsjahr:

2024

Erschienen:

2024

Enthalten in:

Zur Gesamtaufnahme - volume:121

Enthalten in:

Proceedings of the National Academy of Sciences of the United States of America - 121(2024), 12 vom: 19. März, Seite e2316723121

Sprache:

Englisch

Beteiligte Personen:

Bultreys, Tom [VerfasserIn]
Ellman, Sharon [VerfasserIn]
Schlepütz, Christian M [VerfasserIn]
Boone, Matthieu N [VerfasserIn]
Pakkaner, Gülce Kalyoncu [VerfasserIn]
Wang, Shan [VerfasserIn]
Borji, Mostafa [VerfasserIn]
Van Offenwert, Stefanie [VerfasserIn]
Moazami Goudarzi, Niloofar [VerfasserIn]
Goethals, Wannes [VerfasserIn]
Winardhi, Chandra Widyananda [VerfasserIn]
Cnudde, Veerle [VerfasserIn]

Links:

Volltext

Themen:

3D velocimetry
Hydrogeology
Journal Article
Multiphase flow
Porous media

Anmerkungen:

Date Revised 27.03.2024

published: Print-Electronic

Citation Status PubMed-not-MEDLINE

doi:

10.1073/pnas.2316723121

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM369683994