部分水解聚丙烯酰胺与蠕虫状胶束在微米级毛细管中的驱替粘度

部分水解聚丙烯酰胺(HPAMs)被大量地用作三次采油中驱替液的增稠剂，表面活性剂在一定的条件下可以通过自组装形成蠕虫状胶束，具有与高分子相似的增稠的作用。本文在半径为1–10 μm的毛细管中，分别考察了HPAMs与蠕虫状胶束的微观驱替行为，研究结果表示毛细管内腔的尺寸限制了这些非牛顿流体的增稠作用。随着毛细管半径的减小，聚合物溶液的剪切变稀越剧烈，甚至从非牛顿流体转变为牛顿流体的流体行为。结合驱替研究和超滤、电镜的结果，证明了高分子的缠绕结构在毛细管中已被破坏。通过对比驱替数据，蠕虫状胶束在毛细管中能够更大程度地保留宏观的粘度，我们提出表面活性剂能够通过自组装修复被破坏的缠绕结构，比高分子聚合物在微观有限空间中有更好的增稠能力。

In-situ Viscosity of Hydrolyzed Polyacrylamides and Surfactant Worm-Like Micelle Solutions in Microscale Capillaries

Hydrolyzed polyacrylamides (HPAMs) are shear-thinning polymers and have wide application in enhanced oil recovery (EOR), whereas worm-like micelles (WLMs) are known as "living polymers", which can be constructed by the self-assembly of surfactant molecules. Here, a series of experiments were conducted on the fluid behavior of HPAMs and worm-like micelles in microscale capillaries with radii from 1 to 10 μm. The results show that the size of capillary has a decisive effect on the in-situ viscosity of the polymer aqueous phase. It was observed that the shear thinning effect of HPAMs is more pronounced in smaller size of capillaries, where the non-Newtonian polymer flow turns into the Newtonian flow. Evidences from filtration with a microporous filter and transmission electron microscopy (TEM) reveal that the polymer network was broken down when entering into the capillary. Conversely, WLMs can maintain their bulk viscosity to a wide extent. We assume that surfactant molecules may reassemble their aggregates and recover their network in-situ. The results suggest that WLMs have a much lower viscosity, but display similar thickening power compared with large polymers in the low or ultra-low permeability reservoirs.