Patent ID: 9611419
Date: 2017-04-04
CPC Classifications: C04B,C08F,C09K

Claim:
1. A method of making a cementing fluid loss additive, said method consisting of combining a first monomer with a second monomer in a polymerization reaction in the presence of a molecular weight control agent and at a pH in the range of from about 7.0 to about 10.5; wherein: said first monomer is a vinylamide derivative which does include a sulfonic acid function in its structure, and said second monomer is a vinylamide derivative which does not include a sulfonic acid function in its structure; said molecular weight control agent is selected from humic acid, potassium humate, sodium humate and ammonium humate; and the ratio of said first monomer to said second monomer in said reaction is an amount in the range of from about 0.3 to about 2.0 moles of said first monomer per mole of said second monomer.