Effect of molecular weight of polystyrensulfonic acid sodium salt polymers on the precipitation kinetics of sodium bicarbonate

High molecular weight amphoteric terpolymer based on a nonionic monomer, acrylamide (AAm), an anionic monomer, 2-acrylamido-2-methyl-1-propanesulfonic acid sodium salt (AMPS), and a cationic monomer, (3-acrylamidopropyl) trimethylammonium chloride (APTAC), was prepared using free-radical copolymerization in an aqueous solution and characterized by 1H NMR, FTIR, GPC, DLS, zeta potential and viscometry. The polymer was shown to be viscosifying, and therefore can be utilized as a polymer flooding agent in the high salinity and temperature conditions of oil reservoirs. Injection of 0.25 wt.% of amphoteric terpolymer, dissolved in 200-300 g∙L-1 brine, into high and low permeability sand pack models demonstrated that the oil recovery factor (ORF) increases by up to 23-28% in comparison with saline water flooding. This is explained by an increase in the viscosity of brine solution due to disruption of intra- and interionic contacts between oppositely charged AMPS and APTAC moieties, demonstrating the antipolyelectrolyte effect. In high saline water, the anions and cations of salts screen the electrostatic attraction between positively and negatively charged macroions, resulting in expansion of the macromolecule. This phenomenon leads to an increase in the viscosifying effect on the brine solution, thus decreasing the mobility factor (M), which is defined as the ratio of displacing phase mobility (water) to displaced phase mobility (oil).

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The Thermoviscosifying Behavior of Water-Soluble Polymer Based on Graft Polymerization of Pluronic F127 with Acrylamide and 2-Acrylamido-2-methylpropane Sulfonic Acid Sodium Salt

Polymers ◽

10.3390/polym11101702 ◽

2019 ◽

Vol 11 (10) ◽

pp. 1702 ◽

Cited By ~ 1

Author(s):

Quan ◽

Xie ◽

Su ◽

Feng

Keyword(s):

Molecular Weight ◽

Polymer Solution ◽

Sodium Salt ◽

Polymer Concentration ◽

Water Soluble ◽

Pluronic F127 ◽

Water Soluble Polymer ◽

Practical Applications ◽

Acid Sodium Salt ◽

Methylpropionic Acid

A new concept of thermoviscosifying polymers is proposed to address the problems about decreasing viscosity of polymer solution under high temperatures. However, existing thermoviscosifying polymers have complicated synthesis processes and high costs, and both of them restrict the wide practical applications of thermoviscosifying polymers. Although polyethers have the characteristics of thermal gelatinization, they just display thermoviscosifying behaviors only under extremely high concentrations (>15 wt %). Therefore, the graft copolymerization of the commercialized Pluronic F127 (PEO100-PPO65-PEO100) with acrylamide and 2-acrylamide-methylpropionic acid sodium salt was studied here. A series of graft modified polyether polymers were prepared and it was expected to get thermoviscosifying polymers with high molecular weights and low association temperatures. Several factors on thermoviscosifying behaviors were investigated, such as polymerization condition, polymer concentration, hydrophilic monomer, molecular structure and molecular weight. It was also proven that the apparent viscosity of polymer solution is influenced by polymer concentration, molecular weight of polymer, and content of anion groups.

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