Patent ID: 6085840
Filing Date: 2000-07-11
Classification: C04B,C08F,C09K

Abstract:
A method of cementing a pipe in a borehole which penetrates a subterranean formation, said method comprising:forming a cement composition;placing said cement composition in the annulus between said pipe and said formation;permitting said cement composition to set in said annulus whereby a hardened mass of cement is produced;wherein said cement composition is a slurry comprised of water, hydraulic cement and an additive made by polymerizing a vinylamide morpholine derivative with at least one branched N-vinylamide derivative in the presence of an effective quantity of humate,wherein said vinylamide morpholine derivative is selected from compounds represented by the first general formula ##STR5## wherein R.sub.1 is --H or --CH.sub.3 and R.sub.2 is --H, --CH.sub.3 or --CH.sub.2 CH.sub.3 and is positioned on any one of the four carbons in the morpholine ring; andsaid branched N-vinylamide derivative is selected from compounds represented by the second general formula ##STR6## wherein R.sub.3 is --H or --CH.sub.3, R.sub.5 is --H, --CH.sub.3 or --CH.sub.2 CH.sub.3, and R.sub.4 is --H, --CH.sub.3, --CH.sub.2 CH.sub.3, --CH(CH.sub.3).sub.2, --C(CH.sub.3).sub.3 or --C(CH.sub.3).sub.2 CH.sub.2 SO.sub.3 X and X is --H, --Na, --NH.sub.4 or --Ca1/2.