Droplet snap off is one of the most usual phenomena in oil recovery during water injection in water-wet porous media. In this work, the droplet dynamic snap-off process in a short, abrupt constriction is investigated. Three different phenomena, i.e. total breakup, partial breakup and non-breakup, of the nonwetting phase droplets are observed, the flow characteristics of droplets in each phenomenon and relevant physical mechanisms are analyzed. We find that both the initial size and velocity of the droplet greatly influence the breakup process. The viscosity of droplet also affects the breakup state. The critical conditions of each phenomenon are obtained based on dimensionless droplet size and capillary number, which could be used to predict the droplet breakup state. Under a certain capillary number, daughter droplet distribution is influenced by initial droplet size.

在水润湿的多孔介质中注水过程中，油滴溢流是油采收中最常见的现象之一。在这项工作中，研究了液滴在短暂的突然收缩中的动态折断过程。观察了非润湿相液滴的三种不同的现象，即总破裂，部分破裂和不破裂，分析了每种现象中液滴的流动特性以及相关的物理机理。我们发现液滴的初始大小和速度都极大地影响了破碎过程。液滴的粘度也影响破裂状态。基于无因次液滴尺寸和毛细管数获得每种现象的临界条件，这些条件可用于预测液滴破裂状态。在一定的毛细管数下