Patent ID: 8997866
Filing Date: 2015-04-07
Classification: C04B,C09K,E21B

Abstract:
1. A method of cementing in a subterranean formation comprising: introducing a cement composition comprising cement, water, and a lignite-based copolymer into a subterranean formation, wherein the lignite-based copolymer comprises 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; 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.