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).

Pore-scale visualization of hydrogen storage in a sandstone at subsurface pressure and temperature conditions: Trapping, dissolution and wettability.

Hypothesis: Underground hydrogen (H) storage is a potentially viable solution for large-scale cyclic H storage; however, the behavior of H at subsurface pressure and temperature conditions is poorly known. This work investigates if the pore-scale displacement processes in H-brine systems in a porous sandstone can be sufficiently well defined to enable effective and economic storage operations. In particular, this study investigates trapping, dissolution, and wettability of H-brine systems at the pore-scale, at conditions that are realistic for subsurface H storage.

Dynamic Effects during the Capillary Rise of Fluids in Cylindrical Tubes.

The mathematical models for the capillary-driven flow of fluids in tubes typically assume a static contact angle at the fluid-air contact line on the tube walls. However, the dynamic evolution of the fluid-air interface is an important feature during capillary rise. Furthermore, inertial effects are relevant at early times and may lead to oscillations.

New type of pore-snap-off and displacement correlations in imbibition.

Hypothesis: Imbibition of a fluid into a porous material involves the invasion of a wetting fluid in the pore space through piston-like displacement, film and corner flow, snap-off and pore bypassing. These processes have been studied extensively in two-dimensional (2D) porous systems; however, their relevance to three-dimensional (3D) natural porous media is poorly understood. Here, we investigate these pore-scale processes in a natural rock sample using time-resolved 3D (i.

Tunable X-ray dark-field imaging for sub-resolution feature size quantification in porous media.

X-ray computed micro-tomography typically involves a trade-off between sample size and resolution, complicating the study at a micrometer scale of representative volumes of materials with broad feature size distributions (e.g. natural stones).