Stable suspensions of water-soluble polymers and their preparation

摘要

Stable suspensions of water-soluble polymers in a nonsolvent hydrocarbon medium, their preparation and their use for improving the assisted recovery of oil are described. These suspensions consist of at least one aliphatic or aromatic liquid hydrocarbon which is not a solvent for water-soluble polymers, into which there are introduced (per 100 parts by weight of the said liquid hydrocarbon) from 0.1 to 5 parts by weight of a thickening agent such as an alkaline salt of a higher fatty acid (at least 6 carbon atoms), from 40 to 150 parts by weight of solid particles of water-soluble polymer, as well as a proportion from 0.1 to 10 parts by weight of water and/or from 0.1 to 50 parts by weight of C1-C12 aliphatic monoalcohol or of C2-C12 aliphatic diol, per 100 parts by weight of the said water-soluble polymer. These suspensions may also contain from 0.1 to 5 parts by weight of a surface-active agent consisting of a nonionic or anionic hydrophilic emulsifying agent per 100 parts by weight of the liquid hydrocarbon. These stable suspensions bring about an improvement in the use of the water-soluble polymers in the assisted recovery of oil.