Patent ID: 8096359
Filing Date: 2012-01-17
Classification: C04B,C09K,Y02W

Abstract:
1. A method of retarding the set time of a cementitious slurry until placed in a desired location within a gas or oil wellbore, comprising: introducing into the wellbore a pumpable cementitious slurry comprising water, a cement and a water-soluble or water-dispersible set retarder, the set retarder comprising a copolymer of (i) at least one polymerizable ethylenically unsaturated monomer; and (ii) at least one alkoxylated sulfate, phosphate, or carboxylate salt, wherein the consistency of the cementitious slurry is between from about 2 to about 20 Bearden units of consistency and further wherein the amount of water in the cementitious slurry is between from about 30 to 150 weight percent based on the dry weight of the cement; and allowing the slurry to harden to a solid mass; the copolymer being present in the cementitious slurry in an amount sufficient to retard the set time of the cementitious slurry until the cementitious slurry is placed in the desired location within the wellbore.