Foam reduces the gas mobility in porous media both by increasing the effective viscosity of the gas phase and by trapping a large portion of the gas in place. This reduction is directly related to the number density of lamellae in the gas phase. Therefore, understanding the pore-level events associated with lamella generation and destruction processes and investigating the trapped foam behavior are of great importance in modeling foam mobility. In this paper, a pore network model based on the statistical physics method of invasion percolation with memory (IPM) is developed to simulate foam propagation as a drainage process of gas invasion into a porous media initially saturated with a surfactant solution. During this process, lamella generation, destruction, and mobilization are involved. This study sets out to explore the roles of pore level events that lead to foam destruction. To do so, static lamella destruction by capillary suction at the plateau borders is modeled using the Reynolds equation for film thinning and lamella rupture is assumed to occur when the film thickness falls below a certain critical thickness (hfc) at which the maximum disjoining pressure (Πmax) is attained. This mechanism is incorporated in the pore network model to which we add a notional time dependency of the invasion percolation with memory mechanism. Flowing lamellae are assumed to rupture at a fixed limiting capillary pressure (Pcap*) lower than Πmax. Results show that a critical regeneration probability (freg*) is required for the generation of strong foam in the network. The mobilization pressure gradient depends on both the number of lamellae in the flow path and the sizes of the throats that make up of this path. At the same freg, the mobilization pressure gradient markedly decreases after incorporating lamella destruction mechanism. The structure of the displacement pattern of the invading phase at breakthrough changes under the competition between capillary and yield stress-like forces. During transient foam displacement, gas saturation increases, and foam texture becomes finer with increasing freg. The flowing foam fraction increases much more slowly with pressure gradient after accounting for the viscous friction associated with the flow in the already open paths. Comparison with experiments shows that current pore network model can capture the main features of the transient foam flow in porous media.

中文翻译：

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泡沫传播过程中气体捕集和流动性的孔隙网络研究使用具有记忆的入侵渗透

泡沫通过增加气相的有效粘度和将大部分气体捕获在适当的位置来降低多孔介质中的气体流动性。这种减少与气相中薄片的数量密度直接相关。因此，了解与薄片生成和破坏过程相关的孔隙水平事件以及研究被困泡沫行为对于模拟泡沫流动性非常重要。在本文中，基于具有记忆侵入渗流 (IPM) 的统计物理方法开发了一种孔隙网络模型，以模拟泡沫传播作为气体侵入最初用表面活性剂溶液饱和的多孔介质的排水过程。在这个过程中，涉及薄片的产生、破坏和动员。本研究旨在探索导致泡沫破坏的孔隙水平事件的作用。为此，使用雷诺方程对高原边界毛细管吸力造成的静态薄片破坏进行建模，以进行薄膜变薄，并且假定当薄膜厚度低于某个临界厚度 (hfc) 时发生薄片破裂，此时最大分离压力（ Πmax)。这种机制被纳入孔隙网络模型中，我们在其中添加了入侵渗透与记忆机制的概念时间依赖性。假定流动的薄片在低于 Πmax 的固定极限毛细管压力 (Pcap*) 下破裂。结果表明，在网络中生成强泡沫需要临界再生概率 (freg*)。流动压力梯度取决于流动路径中的薄片数量和组成该路径的喉部的尺寸。在相同的频率下，加入薄片破坏机制后，动员压力梯度显着降低。在毛细管力和类屈服应力的竞争下，突破时侵入相位移模式的结构发生了变化。在瞬态泡沫置换过程中，气体饱和度增加，泡沫质地随着 freg 的增加而变细。在考虑与已经打开的路径中的流动相关的粘性摩擦之后，流动的泡沫分数随着压力梯度的增加要慢得多。与实验对比表明，当前的孔隙网络模型可以捕捉多孔介质中瞬态泡沫流动的主要特征。