Patent ID: 6395853
Filing Date: 2002-05-28
Classification: C04B,C08F,C09K

Abstract:
A process for reducing water loss in a petroleum production slurry selected from the group consisting of borehole cement, drilling mud, and completion and clearing-out liquid, said process comprising adding to said slurry a copolymer comprisingA) 5-95% by weight of structural units which are derived from compounds of the formula 1 B) from 1 to 95% by weight of structural units which are derived from compounds of the formula 2 â€ƒand C1) from 1 to 95% by weight of structural units which are derived from compounds of the formula 3 â€ƒor, alternatively to C1), C2) from 1 to 95% by weight of structural units which are derived from compounds of the formula 4 â€ƒin which X is a cation.