Cement compositions and method of cementing casing in a well

A aqueous cement slurry comprising (1) a cement selected from Class A through Class H, (2) at least one polysaccharide, (3) water, and (4) a separately added 1,2-dicarbonyl and wherein said components are present in the following weight percent based on the weight of the cement:

• ______________________________________ Weight Percent ______________________________________ Polysaccharide 0.001-5.0 Water 30-65 1,2-dicarbonyl 0.15-1.0 ______________________________________

A method of cementing casing in the borehole of a well comprising suspending the casing in the borehole of a well, whether vertical or slanted, pumping an aqueous cement slurry comprising (1) a cement selected from Class A through Class H, (2) at least one polysaccharide, (3) water, and (4) a 1,2-dicarbonyl wherein the amount of said 1,2-dicarbonyl is sufficient to obtain a viscosity of such aqueous slurry at 140.degree. F. and atmospheric pressure which is greater than the viscosity of said slurry at 70.degree. F. and atmospheric pressure into the well until said slurry fills that portion of the space desired to be sealed and then maintaining said slurry in place until the cement sets.