Method of cementing using polymeric retarder

Set retarders of copolymers of at least one polymerizable ethylenically unsaturated monomer and at least one alkoxylated sulfate, phosphate or ketonic salt are capable of delaying the hardening of a cementitious slurry when introduced into a subterranean formation until a downhole temperature greater than or equal to 500° F. is obtained, even in the absence of an intensifier. The ethylenically unsaturated monomer is preferably a carboxylic acid, amido carboxylic acid, carboxylic acid ester, amido carboxylic acid ester, hydroxylated alkyl ester of a carboxylic acid or a hydroxylated amido carboxylic acid ester, sulfonic acid, phosphonic acid or amide as well as mixtures thereof and the alkoxylated sulfate, phosphate or ketonic salt is of the formula: wherein unit R1 is H or a C1-C4 alkyl; R2 is -(CH2CH2-O-)n or (-CH2CHCH3-O-)n or a mixture thereof; n ranges from about 1 to about 100; X is an anionic radical selected from -SO3, -PO3 or -COO or a water soluble cationic moiety which counterbalances the valence of the anionic radical X.