Calcium-tolerant N-substituted acrylamides as thickeners for aqueous systems
US4649183A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 10, 1985 |
| Grant date | Mar 10, 1987 |
| Priority date | — |
| Expiry date | Dec 10, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S507/936
- WIPO fieldMacromolecular chemistry, polymers
- WIPO sectorChemistry
Abstract
A water-soluble, charged, random copolymer of acrylamide and an alkali metal salt of an acrylamido-alkanoic acid such as alkali metal 3-acrylamido-3-methylbutanoate, having an average molecular weight of greater than about 50,000, has been found to maintain unusually stable and effective viscosities in the presence of salts such as NaCl and CaCl.sub.2 when added to water in minor amounts, thus making it a highly effective mobility control agent for secondary and tertiary oil recovery methods. Also within the scope of the invention are the acid form of the polymer, as well as terpolymers which additionally contain olefinically unsaturated monomers such as acrylic acid or sodium acrylate.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.