| 摘要 |
An improved water loss control additive for hydraulic cements, particularly hydraulic cements used in subterranean well bore cementing operations, is disclosed. The additive comprises an aqueous solution comprising a tetrapolymer of N-vinyl-2-pyrrolidone, acrylamide and/or methacrylamide, sodium 2-acrylamido-2-methylpropane sulfonate and/or 2-acrylamido-2-methylpropane sulfonic acid, and acrylic acid or sodium acrylate; a base; and electrolyte and a surfactant. |
