Speaker
Description
When matrix-dissolving fluids flow through porous media, a positive feedback loop between fluid movement and chemical reaction creates evolving dissolution patterns. These patterns range from nearly uniform fronts to highly complex, branched channels known as wormholes.
This hydrochemical instability is sensitive not only to flow parameters but also to spatial heterogeneity of the porous media [1,2]. While research has successfully mapped how flow and reaction rates influence the shape (morphology) of these structures, we still lack a deep understanding of their propagation dynamics, namely mechanisms that control how wormholes advance and accelerate in time [3].
To understand the interaction between the evolving flow field and the surrounding porous matrix, time-resolved, high-resolution data are required. We use the capabilities of the ID-19 beamline at the European Synchrotron Radiation Facility (ESRF), to conduct core-flooding experiments and acquire 4D X-ray computed tomography images of developing wormholes. The tomographic data, collected at high temporal frequency, were processed to reconstruct time evolution of the wormholes' 3D geometry. Complementary experiments were performed at the NeXT neutron tomography beamline, using heavy water as a contrast agent to visualize the flow field. Finally, the CT reconstructions were used as input for numerical analysis with a high performance lattice-Boltzmann code (TCLB, [4]) to compute the evolving flow field during porosity changes.
By utilizing these datasets, we quantify geometrical and dynamical observables and confront them with growth theory that approximates a wormhole as an evolving tubular channel [5]. Focusing on natural, highly heterogeneous rock, we benchmark this description against the measured growth rates, branching, and channel competition.
| References | [1] Hoefner, M.L. and Fogler, H.S., 1988. Pore evolution and channel formation during flow and reaction in porous media. AIChE J., 34, pp.45-54 [2] Cooper, M.P., Sharma, R.P., Magni, S., Blach, T.P., Radlinski, A.P., Drabik, K., Tengattini, A. and Szymczak, P., 2023. 4D tomography reveals a complex relationship between wormhole advancement and permeability variation in dissolving rocks. Advances in Water Resources, 175, p.104407 [3] Golfier, F., Zarcone, C., Bazin, B., Lenormand, R., Lasseux, D. and Quintard, M., 2002. On the ability of a Darcy-scale model to capture wormhole formation during the dissolution of a porous medium. J. Fluid Mech., 457, pp.213-254 [4] Ł. Łaniewski-Wołłk, J. Rokicki, Adjoint Lattice Boltzmann for topology optimization on multi-GPU architecture, Computers and Mathematics with Applications, 2016-02-01 [5] Budek, A. and Szymczak, P., 2012. Network models of dissolution of porous media. Phys. Rev. E 86, 056318. |
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| Country | Poland |
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