Dynamic fluid connectivity during steady-state multiphase flow in a sandstone

作者：Reynolds Catriona A^*; Menke Hannah; Andrew Matthew; Blunt Martin J; Krevor Samuel

来源：Proceedings of the National Academy of Sciences, 2017, 114(31): 8187-8192.

DOI：10.1073/pnas.1702834114

• steady state
• pore-scale imaging
• immiscible two-phase flow
• dynamic connectivity
• geologic CO2 storage

The current conceptual picture of steady-state multiphase Darcy flow in porous media is that the fluid phases organize into separate flow pathways with stable interfaces. Here we demonstrate a previously unobserved type of steady-state flow behavior, which we term "dynamic connectivity," using fast pore-scale X-ray imaging. We image the flow of N-2 and brine through a permeable sandstone at subsurface reservoir conditions, and low capillary numbers, and at constant fluid saturation. At any instant, the network of pores filled with the nonwetting phase is not necessarily connected. Flow occurs along pathways that periodically reconnect, like cars controlled by traffic lights. This behavior is consistent with an energy balance, where some of the energy of the injected fluids is sporadically converted to create new interfaces.

• 出版日期2017-8-1