Patent ID: 8759260

Claim:
A method of forming a wellbore fluid additive, the method comprising reacting an optionally substituted C 2-4 aminoalkylsulfonic acid and a polymer comprising the following two types of repeat units: wherein R 1 is optionally substituted C 10-28 alkyl; and R 2 and R 3 are independently hydrogen, optionally substituted C 1-12 alkyl, optionally substituted C 6-10 aryl, optionally substituted C 6-10 heteroaryl, halo, OH, SH, C 0-12 amino, C 1-12 alkoxy, C 1-12 alkyl sulfide, or C 1-12 acyloxy; wherein the reacting occurs in a mixture of solvents further comprising a dipolar aprotic solvent, and water; wherein at least about 1% by weight of water is added to the dipolar aprotic solvent and wherein the optionally substituted C 2-4 aminoalkylsulfonic acid is reacted with a base in an amount of 0.8 equivalents to 2.5 equivalents per mole of optionally substituted C 2-4 aminoalkylsulfonic acid prior to and/or simultaneously with reaction with the polymer.