The displacement of a nonowetting fluid by a wetting fluid in a pore-throat (expansion-contraction-expansion) channel may result in the breakup of the non-wetting fluid into separate droplets/bubbles. This phenomenon, referred to as snap-off, choke-off, or breakup (Herring et al., 2018;Xu, Liang, et al., 2017;, occurs when the capillary pressure at its leading part exceeds that at the pore-throat junction during the imbibition process. It is an important process in many subsurface engineering applications, such as aquifer remediation (