Mechanical stability of high-molecular-weight polyacrylamides and an (acrylamido tert-butyl sulfonic acid)-acrylamide copolymer used in enhanced oil recovery

Abdul Aziz Al-Hashmi, Rashid Al-Maamari, Ibtisam Al-Shabibi, Ahmed Mansoor, Hamed Al-Sharji, Alain Zaitoun

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6 Citations (Scopus)

Abstract

High-molecular-weight partially hydrolyzed and sulfonated polyacrylamides are widely used in enhanced oil recovery (EOR). Nonionic polyacrylamide and polyacrylamide-based microgels are also used in water shut-off treatments for gas and oil wells. A comparative study of the mechanical degradation for three linear polyacrylamides and a microgel is presented. Mechanical degradation is quantified from the loss of the viscosity of the polymer solution as it passes through a stainless steel capillary with a length of 10 cm and an internal diameter of 125 μm. The critical shear rate above which degradation increases exponentially was found to depend on the chemical structure of the polymer, molecular weight, and electrolyte strength. The nonionic polyacrylamide shows higher degradation and lower critical shear rate compared with a sulfonated polyacrylamide with similar molecular weight. Moreover, the nonionic polyacrylamide with a higher molecular weight results in lower mechanical degradation. The higher mechanical stability of the sulfonated polymer is attributed to the higher rigidity of its molecules in solution. On the other hand, the ability of the high-molecular-weight polymers to form transient, flow-induced microgels boost their mechanical stability. This ability increases with the increase in the molecular weight of the polymer. Indeed, the microgel solution used in this study demonstrates exceptional mechanical stability. In general, mechanical stability of linear polymers used in chemical enhanced oil recovery can be enhanced by tailoring a polymer that has large side groups similar to the sulfonated polyacrylamide. Also, polyacrylamide-based microgels can be applied if high mechanical stability is required.

Original languageEnglish
Article number40921
JournalJournal of Applied Polymer Science
Volume131
Issue number20
DOIs
Publication statusPublished - Oct 15 2014

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Keywords

  • copolymers
  • degradation
  • microgels
  • oil and gas
  • rheology

ASJC Scopus subject areas

  • Materials Chemistry
  • Polymers and Plastics
  • Surfaces, Coatings and Films
  • Chemistry(all)

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