Electrolyte-containing aqueous polymer solution and method for tertiary recovery of petroleum

摘要

The invention relates to an electrolyte-containing aqueous polymer solution having a salt content of 5 to 35 wt% with respect to the total amount of the polymer solution. Said polymer solution contains: at least one dissolved synthetic copolymer, which contains structural units that are derived from (i) at least one amide of an ethylenically unsaturated carboxylic acid and from (ii) at least one ethylenically unsaturated sulfonic acid or alkali metal salts and/or ammonium salts thereof; and at least one non-ionic surfactant selected from the group of the alkoxylated fatty alcohols, the alkoxylated alkylphenols, and/or the alkoxylated fatty acids, with the stipulation that the average degree of alkoxylation of said surfactants is 8 to 10. The aqueous polymer solution is used in the tertiary recovery of petroleum and is distinguished by very good filtration behaviour, in particular if saline water is present.