The invention discloses a neutral
oil well cement retarder with ultrahigh
temperature resistance and low
dilution property, which is formed by polymerizing 2-
acrylamide-2-methylpropanesulfonic acid,
itaconic acid and imidazolidone, the
mass parts of the 2-
acrylamide-2-methylpropanesulfonic acid, the
itaconic acid and the
imidazolidinone are respectively 120 to 150 parts of the 2-
acrylamide-2-methylpropanesulfonic acid, 28 to 38 parts of the
itaconic acid and 5 to 10 parts of the
imidazolidinone. The invention also provides a preparation method of the neutral ultrahigh-temperature-resistant low-
dilution oil well cement retarder. The neutral ultrahigh-temperature-resistant low-
dilution oil well cement retarder is prepared by the method. The neutral ultra-high-temperature-resistant low-dilution oil well cement retarder provided by the invention is used for deep wells and ultra-deep wells, and has the advantages of
salt resistance, effective prolonging of thickening time, large
temperature difference resistance, meeting of top strength requirements,
neutral pH, meeting of
environmental protection requirements, no thickening at low temperature, no
flocculation at high temperature and no
sedimentation at high temperature when being used for deep wells and ultra-deep wells at the temperature of 240 DEG C or above; and well cementation requirements of deep wells and ultra-deep wells can be met.