Cement compositions comprising lignite-based grafted copolymers and methods of use

A method of cementing in a subterranean formation comprising:

• introducing a cement composition comprising cement, water, and a lignite-based copolymer into a well bore having a bottom hole circulating temperature of less than or equal to about 100° F., wherein the lignite-based copolymer comprises:
• a backbone in an amount of about 20% to about 40% by weight of the lignite-based copolymer, the backbone comprising causticized lignite;
• and
• grafted pendant groups in an amount of about 60% to about 80% by weight of the lignite-based copolymer, the grafted pendant groups comprising sodium 2-acrylamido-2-methylpropanesulfonate and N,N-dimethylacrylamide in a molar ratio of sodium 2-acrylamido-2-methylpropanesulfonate and N,N-dimethylacrylamide of about 10/90 to about 60/40;
• and
• allowing the cement composition to set in the subterranean formation, wherein the cement composition has a transition time of less than or equal to about 30 minutes.

A cement composition comprising:

• cement;
• water;
• and
• a lignite-based copolymer comprising a lignite backbone in an amount of about 10% to about 50% by weight of the lignite-based copolymer and pendant groups in an amount of about 50% to about 90% by weight of the lignite-based copolymer, wherein the pendant groups comprise a first grafted monomer selected from the group consisting of 2-acrylamido-2-methylpropanesulfonic acid, a salt of 2-acrylamido-2-methylpropanesulfonic acid, and combinations thereof, and a second grafted monomer comprising N,N-dimethylacrylamide, wherein a ratio of the first grafted monomer to the second grafted monomer is from about 10/90 to about 60/40,
• wherein the cement composition has a transition time at 60° F. and 6,300 psi of less than or equal to about 150 minutes.