| abstract |
A polymeric composition for reducing fluid loss in drilling muds and cement compositions used in the recovery of oil and gas is obtained by free radical initiated polymerization, in an aqueous admixture, of (a) lignin, modified lignins, lignite, brown coal, modified brown coal, or mixtures thereof, and, (b) at least one water-soluble vinyl monomer chosen from the group consisting of (meth) acrylic acid, (meth) acrylamide, hydroxyethyl acrylate, hydroxypropyl acrylate, vinyl acetate, methyl vinyl ether, ethyl vinyl ether, N-methyl (meth) acrylamide, N,N-dimethyl (meth) acrylamide, vinyl sulfonate, and 2-acrylamido-N-methylpropane sulfonic acid, and then recovering said polymeric composition. u |