高盐诱导蠕虫状胶束的泡沫稳定机制

泡沫在常规与非常规油气开发、CO₂埋存上的应用效果与其稳定性密切相关。以挖掘高盐储层自身潜力为目标,利用盐诱导油酸酰胺丙基甜菜碱(ODAB)构建高稳泡沫,并结合ODAB的表面性质、体相性质以及液膜薄化行为探究主导其稳定性的关键机制。研究结果表明,在低ODAB浓度下(质量分数为0.02%~0.05%),泡沫稳定性由表面扩张黏弹性控制,高盐可降低体相与表面间的分子扩散交换速度,令表面扩张黏弹性增强,泡沫稳定性提高。随着ODAB浓度增加,虽表面扩张黏弹性降低,但高盐可诱导蠕虫状胶束形成、生长并逐渐紧密纠缠,从而促使体相黏弹性增强,液膜薄化特征转变、速度下降。在高ODAB浓度下(质量分数为0.05%~1.00%),体相黏弹性对盐度、ODAB浓度变化的响应与泡沫稳定性完全一致,是ODAB泡沫稳定性改善的决定性因素。

Foam stabilization mechanism of high-salinity-induced worm-like micelles

The application effect of foam in conventional and unconventional oil and gas development and CO₂storage is closely related to its stability. Aiming to exploit the potential of high-salinity reservoirs, this paper produces highly stable foam using high-salinity-induced oleicyl dimethylamidopropyl betaine (ODAB), and explores the key mechanisms controlling the stability of ODAB when considering its surface properties, bulk phase properties, and liquid film thinning behavior. The results show that at low ODAB concentrations (mass fraction 0.02 % -0.05 % ), the foam stability is controlled by the surface dilatational viscoelasticity. High salinity can reduce the molecular diffusion and exchange velocity between the bulk phase and the surface, which enhances the surface dilatational viscoelasticity and the foam stability. When the ODAB concentration increases, although the surface dilatational viscoelasticity decreases, the high salinity induces the formation, growth, and gradually tight entanglement of worm-like micelles, which leads to the enhancement of bulk phase viscoelasticity, the transformation of liquid film thinning characteristics and the deceleration of liquid film thinning. At high ODAB concentrations (mass fraction 0.05 % -1.00 % ), the response of bulk phase viscoelasticity to changes in salinity and ODAB concentration is consistent with that of the foam stability, which is the decisive factor for the improvement of ODAB foam stability.