Okesanjo Omotola, Aubry Guillaume, Behrens Sven, Lu Hang, Meredith J Carson
School of Chemical and Biomolecular Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA.
Polymer Science & Materials Chemistry, Exponent Inc., Atlanta, Georgia 30326, USA.
Lab Chip. 2023 Oct 10;23(20):4434-4444. doi: 10.1039/d3lc00419h.
Surfactant-free capillary foams (CFs) are known to be remarkably tolerant to oil, and possess unique stability and flow properties. These properties result from the presence of oil-and-particle-coated bubbles that are interconnected by a dense particle-oil capillary network. In this work, we present a study of the dynamics of capillary foams flowing through a porous micromodel. We determine that despite the presence of oil-particle networks, CFs can flow through a microporous environment and that above a threshold flowrate, >80% of foam pumped through the micromodel can be recovered. In addition, we highlight the absence of steady state in CF flow and identify the underlying phenomena including the increasing apparent viscosity, reconfigurable flow paths, and intermittent clogging of the micromodel from an oil-particle composite and bubbles trapped in pores. We also characterize bubble dynamics and show that CFs surprisingly exhibit the same bubble generation and destruction mechanisms as classical foams despite the absence of surfactants. Our observations suggest that the porous medium plays a key role in generating uniformly sized bubbles and that capillary foams in a microporous environment tend to reconfigure their flow paths in a manner that may provide opportunities for increased sweep efficiency in enhanced oil recovery.
无表面活性剂毛细管泡沫（CFs）已知对油具有显著的耐受性，并具有独特的稳定性和流动特性。这些特性源于存在由致密的颗粒 - 油毛细管网络相互连接的涂有油和颗粒的气泡。在这项工作中，我们展示了对通过多孔微模型流动的毛细管泡沫动力学的研究。我们确定，尽管存在油 - 颗粒网络，但CFs可以流过微孔环境，并且在高于阈值流速时，通过微模型泵送的泡沫中超过80%可以回收。此外，我们强调了CF流动中不存在稳态，并确定了潜在现象，包括表观粘度增加、可重构流动路径以及微模型因油 - 颗粒复合材料和困在孔隙中的气泡而间歇性堵塞。我们还表征了气泡动力学，并表明尽管没有表面活性剂，CFs令人惊讶地表现出与经典泡沫相同的气泡产生和破坏机制。我们的观察结果表明，多孔介质在产生均匀大小的气泡中起关键作用，并且微孔环境中的毛细管泡沫倾向于以一种可能为提高强化采油中的波及效率提供机会的方式重构其流动路径。
