| 摘要 |
<p>A cementing composition for use in cementing operations for oil and gas wells having bottom hole circulating temperatures above about 200 DEG F (93 DEG C), comprising a salt or fresh water cement slurry, a water soluble form of borate, and a terpolymer, wherein said terpolymer is comprised of about 10-65 mole percent of a strong acid monomer selected from sodium vinylsulfonate, 2-acrylamido-2-methyl propane sulfonic acid, and vinyl benzene sulfonic acid; about 10-60 mole percent of a weak acid monomer selected from acrylic acid, methacrylic acid, ethacrylic acid and vinyl acetic acid; and about 10-60 mole percent of a nonionic monomer selected from acrylamide, N-vinylpyrrolidone and N,N-dimethylacrylamide; wherein the average molecular weight of said terpolymer is between about 10 000 and about 100 000. </p> |
