Abstract: This invention relates to water-soluble or water-swellable polymers, containing a) 25-35 mol. % of one or more recurrent structural units of formula (1), where R1 and R2 represent hydrogen, methyl or ethyl, A represents a linear or branched C1-C12-alkylene, and Q+ stands for NH4+, Li+, Na+, K+, ½ Ca++, ½ Mg++, ½ Zn++, ? Al+++, or organic ammonium ions of the formula [HNR5R6R7]+, b) 3 to 8 mol. % of one or more recurrent structural units of formula (2), where R1 represents hydrogen, methyl, or ethyl, X+ stands for H+, NH4+, Li+, Na+, K+, ½ Ca++, ½ Mg++, ½ Zn++, ? Al+++, or organic ammonium ions of the formula [HNR5R6R7]+, B is a linear or branched alkylene group with 1 to 6 carbon atoms, and n is a whole number between 0 and 5, and c) 57 to 72 mol. % of a (meth)acrylamide.

Abstract: This invention relates to water-soluble or water-swellable polymers, containing a) 25-35 mol. % of one or more recurrent structural units of formula (1), where R1 and R2 represent hydrogen, methyl or ethyl, A represents a linear or branched C1-C12-alkylene, and Q+stands for NH4+, Li+, Na+, K+, ½ Ca++, ½ Mg++, ½ Zn++, ? Al+++, or organic ammonium ions of the formula [HNR5R6R7]+, b) 3 to 8 mol. % of one or more recurrent structural units of formula (2), where R1 represents hydrogen, methyl, or ethyl, X+stands for H+, NH4+, Li+, Na+, K+, ½ Ca++, ½ Mg++, ½ Zn++, ? Al+++, or organic ammonium ions of the formula [HNR5R6R7]+, B is a linear or branched alkylene group with 1 to 6 carbon atoms, and n is a whole number between 0 and 5, and c) 57 to 72 mol. % of a (meth)acrylamide.

Abstract: This invention relates to water-soluble or water-swellable polymers, containing a) 25-35 mol. % of one or more recurrent structural units of formula (1), where R1 and R2 represent hydrogen, methyl or ethyl, A represents a linear or branched C1-C12-alkylene, and Q+ stands for H+, NH4+, Li+, Na+, K+, ½Ca++, ½Mg++, ½Zn++, ?Al+++, or organic ammonium ions of the formula [HNR5R6R7]+, b) 3 to 8 mol. % of one or more recurrent structural units of formula (2), where R1 represents hydrogen, methyl, or ethyl, X+ stands for H+, NH4+, Li+, Na+, K+, ½Ca++, ½Mg++, ½Zn++, ?Al+++, or organic ammonium ions of the formula [HNR5R6R7]+, B is a linear or branched alkylene group with 1 to 6 carbon atoms, and n is a whole number between 0 and 5, and c) 57 to 72 mol. % of a (meth)acrylamide.

Abstract: The invention relates to the use of vinyl phosphonic acid or a salt thereof for improving the biodegradability of mixed polymers, comprising 25 to 99.5% by weight of structural units of one or more monomers selected from the group made of compounds of formula (1) and formula (3), where R1 and R2 independently are hydrogen or C1-C4-alkyl, formula (4), where n is 3, 4, or 5, and formula (5), where X is OH or for NR3R4, and R3 and R4 independently are H or C1 to C4-alkyl, in that 0.5 to 25% by weight of vinyl phosphonic acid is polymerized into the mixed polymer.

Abstract: Provided herein are foamed cement composition that comprises a hydraulic cement, water, a gas, a foaming and stabilizing surfactant, and a fluid loss control additive comprising a copolymer.

Abstract: Provided herein are methods that comprise: providing a foamed cement composition that comprises a hydraulic cement, water, a gas, a foaming and stabilizing surfactant, and a fluid loss control additive comprising a copolymer; placing the foamed cement composition in a location to be cemented; and allowing the foamed cement composition to set.

Abstract: The invention relates to copolymers comprising a) 5-95% by weight of structural units which are derived from compounds of the formula 1 b) from 1 to 95% by weight of structural units which are derived from compounds of the formula 2  and c1) from 1 to 95% by weight of structural units which are derived from compounds of the formula 3  or, alternatively, to c1), c2) from 1 to 95% by weight of structural units which are derived from compounds of the formula 4  n which X is a cation. The copolymers according to the invention are suitable as a fluid loss additive for water-based drilling muds and for cement slurries in deep wells, for completion and clearing-out liquids and for water shut-off in production probes.

Abstract: The present invention relates to copolymers consisting of (a) 1-99% by weight of structural units of the formula (1)  where R1 is hydrogen or methyl, R4 is C1-C22-alkylene, R5 is C1-C22-alkyl or hydrogen, and X is ammonium, lithium, sodium, potassium, an amine or a mixture of these substances, and (b) 99-1% by weight of structural units of the formula (2)  where R1 is hydrogen or methyl, R2 and R3, independently of one another, are hydrogen, or C2-C22-alkyl, wherein component b) is not hydrolysed and the copolymers have been prepared by a solution precipitation polymerization in a nonaqueous solvent or a water-miscible, organic solvent having a low water content which is a precipitant for the copolymer. The invention furthermore relates to a process for cementing subterranean wells using a cement slurry comprising the following components: a) water of various salinity cement a novel copolymer in a concentration of 0.01-5% bwoc, preferably from 0.05 to 0.