Lima Nicolle, Parsa Shima, Paciornik Sidnei, Carvalho Marcio S
Department of Mechanical Engineering, Pontifícia Universidade Católica do Rio de Janeiro, Rio de Janeiro, Brazil.
School of Physics and Astronomy, Rochester Institute of Technology, Rochester, USA.
Sci Rep. 2023 Dec 9;13(1):21802. doi: 10.1038/s41598-023-48442-5.
Foam has been shown to have great potential to significantly improve sweep efficiency during gas injection in oil recovery, remediation of contaminated sites, gas storage, and acidification processes. The gas mobility reduction largely depends on the generation and stability of lamellae in the pore space that traps the gas phase. Most available analyses focus on foam formation during the co-injection of gas and liquid phases at different fractional flow (foam quality) or flow of foam formed before being injected in the porous media. During surfactant-alternating-gas (SAG) injection, foam is formed as the aqueous phase is displaced by the gas slug that follows. The dynamics of lamellae formation and their stability are different from that of a co-injection process, since the amount of surfactant available to stabilize the gas-liquid interfaces is fixed as fresh surfactant solution is not injected together with the gas phase. This work studies foam formation during the drainage of a surfactant solution by gas injection at a fixed flow rate. A transparent microfluidic model of a porous medium is used in order to enable the correlation of pore-scale phenomena and macroscopic flow behavior. The results show that the maximum number of lamellae increases with surfactant concentration, even much above the critical micelle concentration (CMC). The availability of surfactant molecules needed to stabilize newly formed gas-liquid interfaces rises with concentration. The higher number of lamellae formed at higher surfactant concentration leads to stronger mobility reduction of the gas phase and longer time needed for the gas to percolate through the porous medium.
在石油开采、污染场地修复、气体储存和酸化过程中，泡沫已被证明在气体注入期间具有显著提高波及效率的巨大潜力。气体流动性的降低很大程度上取决于孔隙空间中捕集气相的薄片的生成和稳定性。大多数现有分析聚焦于在不同分流率（泡沫质量）下同时注入气相和液相时的泡沫形成，或在注入多孔介质之前形成的泡沫的流动。在表面活性剂交替注气（SAG）过程中，随着后续气段塞驱替水相，泡沫形成。薄片形成的动力学及其稳定性与同时注入过程不同，因为稳定气液界面的可用表面活性剂数量是固定的，因为新鲜表面活性剂溶液不与气相一起注入。这项工作研究了在以固定流速注气排液表面活性剂溶液过程中的泡沫形成。使用了多孔介质的透明微流控模型，以便能够关联孔隙尺度现象和宏观流动行为。结果表明，薄片的最大数量随着表面活性剂浓度的增加而增加，甚至远高于临界胶束浓度（CMC）。稳定新形成的气液界面所需表面活性剂分子的可用性随浓度增加。在较高表面活性剂浓度下形成的较多薄片导致气相流动性降低更强，且气体渗透过多孔介质所需的时间更长。
