| abstract |
Methods of retarding the setting of a cement composition comprise including one or more secondary amines substituted with a carboxyl group or salts thereof (e.g., 3-hydroxy N,N′-iminodisuccinic acid) in the cement composition. The inclusion of such materials in cement compositions may be highly beneficial. In wellbores having BHCT's of less than or equal to about 250° F., the use of the secondary amine as the set retarder ensures that the thickening time of the cement composition is sufficient to allow the cement composition to be pumped to its desired downhole location. Further, the secondary amine may be used in combination with conventional set retarders to enhance the ability of those retarders to increase the thickening time of the cement composition at higher BHCT's, e.g., from about 250° F. to about 525° F. |