The development of intermittent multiphase fluid flow pathways through a porous rock

Red noise in steady-state multiphase flow

“…For experiments 1-3 in Figure 2, there is a clear cycle in the pressure data, with a period of approximately 10 minutes. From the X-ray images acquired during these experiments, 10 minutes corresponds to the longest time frame also observed for changes in pore-scale fluid occupancy [26]. However, other timescales are observed in the X-ray images.…”

“…The observation that the dynamics of flow in porous media involves phenomena that occur over a wide range of times and distances has necessitated research to bridge these scales [17][18][19][20][21][22][23]. But with many flow regimes possible at the pore scale, ranging from ganglion dynamics [24,25], intermittent pathway flow [26][27][28], and connected pathway flow (with flow regimes able to exist simultaneously in the pore space [29]), and the heterogeneous nature of most pore spaces of interest, research conducted at the pore scale has often been analysed independently of the impact on larger scale flow. As a result, the dynamics at the pore scale are overlooked in the framework of continuum scale models.…”

“…As a result, the dynamics at the pore scale are overlooked in the framework of continuum scale models. However, the pore scale dynamics may play a role in larger scale flow properties, and will influence plume migration [17,26,30].…”

“…Typically, the pressure measured during steady-state, which is used to calculate the relative permeability of the fluid phases, shows notable fluctuations [3,25,26,28,29,[31][32][33][34][35]. Historically these fluctuations have been discounted as noise or a failed experiment, such that there is extensive literature on steady-state relative permeability, but in most cases the raw pressure data is not shown.…”

“…However, other timescales are observed in the X-ray images. The methodology of the X-ray imaging is described elsewhere [26,45]. A subvolume of the pore space during experiment 1 is shown in Figure 3.…”