Performance research and application of oil cement retarder SDH-2.

To meet the special requirements of cement retarder for deep cementing,a high temperature and salt tolerant cement retarder was developed.In this paper,the preparation of SDH-2 was introduced,and evaluation results of retardation,thermal stability,salt tolerance,compatibility with other additives and compressive strength of cement stone were also presented.Experimental data showed that SDH-2 exhibits good retarding ability to oil well cement slurries at 40 to 204 ℃,and the thickening time is adjustable and the thickening curve is in good shape;It works well with the presence of other salts;it is compatible with dispersants,filtrate loss controllers and the set slurry has high compressive strength.SDH-2 has been applied in 6 wells.Field using verified that it could help solve problems onsite such as unstable cement slurry properties and uncontrollable thickening time in deep wells.The slurry with SDH-2 in has good rheological property,satisfying rheological requirements of cement slurry for different down hole conditions.At the same time compressive strength develops rapidly,and the stone is stable at high temperature.