A novel CO₂-responsive hydrogel for intelligent control of gas channeling in CO₂– enhanced oil recovery (CO₂-EOR) and geological CO₂ storage has been developed. A monomeric long-chain tertiary amine surfactant (HXB-2) that has specific amide and carboxyl groups was synthesized. The surfactant can interact with CO₂ in aqueous solution to increase the viscosity and induce gelation. The hydrogel is irreversible and does not revert to solution phase after N₂ bubbling. It shows excellent structural stability and thermal resistance and the viscosity remains four times higher than that of the initial solution upon heating. For the mechanism, HXB-2 protonates in CO₂ environment and self-assembles into worm-like micelles (WLMs) under synergistic forces of hydrophobic interaction, hydrogen bonding, and electrostatic interaction, which further crosslink to form a three-dimensional (3D) network to induce gelation. The hydrogel can be formed in-situ to control gas channeling intelligently and redirect the gas to unswept low-permeability channels. It can enhance the recovery rate by 23.53 % and the maximum seepage resistance reaches 29.45 MPa·min·cm⁻³ for water-alternatinggas flooding. Moreover, by having spontaneous association and shear-dissociation properties, the hydrogel in the rock pores causes minimal damage to the reservoir. This study provides valuable insights and empirical support for the development of irreversible CO₂-responsive hydrogels for CO₂ chemical sequestration and gas channeling control to help EOR and geological CO₂ storage.

中文翻译：

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一种智能 CO2 响应性水凝胶，适用于提高石油采收率和 CO2 地质封存


已经开发了一种新型的 CO₂ 响应水凝胶，用于智能控制 CO₂ 中的气体通道 - 提高石油采收率 （CO_2-EOR） 和地质 CO₂ 封存。合成了具有特异性酰胺和羧基的单体长链叔胺表面活性剂 （HXB-2）。表面活性剂可与水溶液中的 CO₂ 相互作用，以增加粘度并诱导凝胶化。水凝胶是不可逆的，在 N₂ 鼓泡后不会恢复到溶液相。它表现出优异的结构稳定性和耐热性，加热后粘度仍比初始溶液高四倍。对于机制，HXB-2 在 CO₂ 环境中质子化，并在疏水相互作用、氢键和静电相互作用的协同作用下自组装成蠕虫状胶束 （WLM），进一步交联形成三维 （3D） 网络以诱导凝胶化。水凝胶可以在原位形成，以智能控制气体通道，并将气体重定向到未扫过的低渗透通道。它可以提高 23.53 % 的采收率，水交替驱的最大抗渗性达到 29.45 MPa·min·cm⁻³。此外，通过具有自发缔合和剪切解离特性，岩石孔隙中的水凝胶对储层造成的损害最小。本研究为开发用于 CO₂ 化学封存和气体通道控制的不可逆 CO₂ 响应性水凝胶提供了有价值的见解和实证支持，以帮助 EOR 和地质 CO₂ 封存。