Methods of cementing in subterranean zones, improved cement compositions
and improved additives are provided. The compositions are basically comprised of
a hydraulic cement, sufficient water to form a slurry and an additive for providing
improved rheology, fluid loss control and set retardation comprised of carboxymethylhydroxyethylcellulose
having in the range of from about 0.62 to about 2.21 moles of hydroxyethyl substitution
and in the range of from about 0.44 to about 0.52 degrees of carboxymethyl substitution
and a 2% by weight aqueous solution of the carboxymethylhydroxyethylcellulose has
a Hppler viscosity in the range of from about 55 mPa.s to about 359 mPa.s.