CPC C08F 220/56 (2013.01) [C09K 8/588 (2013.01); C09K 8/64 (2013.01); C09K 8/80 (2013.01); E21B 43/20 (2013.01); E21B 43/267 (2013.01); C08F 2800/10 (2013.01)] | 17 Claims |
1. An auto-invertible inverse emulsion comprising:
oil;
water;
at least one water-in-oil surfactant; and
at least one polymer having a molecular weight of between 5 and 30 million g/mol and containing:
monomer units of at least one water-soluble monomer selected from acrylamide, 2-acrylamido 2-methylpropane sulfonic acid (ATBS), acrylic acid (AA), and quaternized or salified dimethylaminoethyl acrylate (ADAME), and
10−5 to 5 mol % of a lower critical solution temperature (LCST) macromonomer, said LCST macromonomer having a molecular weight of between 500 and 200,000 g/mol and having units from:
at least one monomer selected from AA, ATBS, and quaternized or salified dimethylaminoethyl methacrylate (MADAME); and
at least one LCST monomer selected from diethylacrylamide, N-isopropylacrylamide, dimethylacrylamide, and ter-butylacrylamide,
provided that where the monomer units of the at least one water-soluble monomer are units of ATBS, the LCST macromonomer does not have units from AA or ATBS.
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