| 摘要 |
<p>A novel copolymer which is obtained through copolymerization of (A) N-vinylacetamide in an amount of 20-90 mass%; (B) 2-acrylamido-2-methyl-propanesulfonic acid and/or a salt thereof in an amount of 7-70 mass%; and (C) a vinyl monomer other than said (A) and (B) in an amount of 3-40 mass% (the total amount of said (A), (B) and (C) is 100%), and a drilling-mud-conditioning agent characterized by containing the copolymer. A drilling-mud-conditioning agent of the present invention can impart to drilling mud high fluidity, lubricity, and resistance to loss of water, even under high-temperature and high-pressure conditions and when the drilling mud contains a large amount of salts.</p> |
