Shear Viscosity of Poly (Acrylamide/Acrylic Acid) Solutions

Abstract

SummaryAcrylamide (AAm)/Acrylic acid (AAc) copolymers are being used in a wide spectrum of applications, from which enhanced oil recovery (EOR) is the target application in this research study. The shear viscosity of the copolymer solution is extremely important in determining the performance properties of AAm/AAc copolymers. A series of copolymers with selected properties were prepared to study the effect of polymer concentration, copolymer composition, and salinity on the shear viscosity of the copolymer solutions. The results revealed the considerable effect of solution concentration and salinity on shear viscosity. Moreover, the behavior of the copolymer composition showed a maximum with respect to shear viscosity.

Design of Tailor‐Made Water‐Soluble Copolymers for Enhanced Oil Recovery Polymer Flooding Applications

“…The results from the shear viscosity tests suggested that polymer 2 with cum F AAm = 0.768 (see Table ) has the highest shear viscosity at the studied shear rates. This is in agreement with results from our previous study of the copolymer shear viscosity, which suggested a behavior with the maximum shear viscosity exhibited around cum F AAm = 0.72 . By having more AAm units in the copolymer, there is a higher chance for getting longer polymer chains, which contributes to higher chain entanglements and shear viscosity.…”

“…This is in agreement with results from our previous study of the copolymer shear viscosity, which suggested a behavior with the maximum shear viscosity exhibited around cum F AAm = 0.72. [11] By having more AAm units in the copolymer, there is a higher chance for getting longer polymer chains, which contributes to higher chain entanglements and shear viscosity. However, there is a limiting copolymer composition, above which the shear viscosity decreases with further increases in the AAm fraction in the copolymer.…”

“…On the other hand, a high percentage of AAc in the copolymer made the copolymer too sensitive toward brine salinity, which is not desirable. Furthermore, copolymers with about 70% cumulative fraction of AAm exhibited the highest shear viscosity . Hence, the percentage of AAm in the copolymer was targeted between 65% and 95% to “bracket” this region of maximum viscosity enhancement.…”

“…Furthermore, copolymers with about 70% cumulative fraction of AAm exhibited the highest shear viscosity. [11] Hence, the percentage of AAm in the copolymer was targeted between 65% and 95% to "bracket" this region of maximum viscosity enhancement. A total monomer concentration of 1.5 mol L −1 was selected to make the chains longer, which was desirable for polymer flooding because higher molecular weight polymers led to higher solution viscosity for a given polymer mass concentration.…”

Evaluation of Polymeric Materials for Chemical Enhanced Oil Recovery

“…Not only do researchers need to be aware of charge effects (in the polyelectrolyte case), but they should also consider the fractions of unique comonomers in a multicomponent material. For example, a high acrylamide fraction is often desirable in copolymers for polymer flooding; in contrast, too much acrylic acid can lead to brine sensitivity [71]. Other comonomers (like 2-acrylamido-2-methylpropane sulfonic acid, acryloyl hydrazide, or n-vinyl pyrrolidone) may provide additional benefits, like improved mechanical and/or thermal stability [26][27][28]31,33].…”