Acta Phys. -Chim. Sin. ›› 2016, Vol. 32 ›› Issue (1): 365-372.doi: 10.3866/PKU.WHXB201511102

• ARTICLE • Previous Articles     Next Articles

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

Ye-Chang LU1,Wen-Hong LI2,3,Yong-Qiang ZHANG2,3,Xue-Feng LI1,Jin-Feng DONG1,*()   

  1. 1 College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072, P. R. China
    2 National Engineering Laboratory for Exploration and Development of Low-Permeability Oil & Gas Fields, Xi'an 710021, P. R. China
    3 Research Institute of Exploration and Development, PetroChina Changqing Oilfield Company, Xi'an 710021, P. R. China
  • Received:2015-09-30 Published:2016-01-13
  • Contact: Jin-Feng DONG E-mail:jfdong@whu.edu.cn
  • Supported by:
    the National Natural Science Foundation of China(21573164, 21273165);PetroChina Changqing Oilfield Co

Abstract:

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.

Key words: Micro-scale capillary flows, In-situ viscosity, HPAMs, Worm-like micelles, Capillary pressure

MSC2000: 

  • O647