A viscosified aqueous solution, optionally for use in a subterranean wellbore, is made by reacting in aqueous solution (i) an initial polymer with either carboxylic acid or amino groups on its polymer chain, (ii) a second compound with an amino group or carboxylic acid group, and (iii) a coupling agent, so that molecules of the second compound join to the polymer chain through amide groups, thereby forming an aqueous solution of a modified polymer which, without separation from the aqueous solution, participates in cross-linking thereby enhancing viscosity of the solution. The second compound may include hydrophobic groups so that the modified polymer contains hydrophobic groups and is able to cross-link with itself or a viscoelastic surfactant through association of hydrophobic groups (without covalent bond formation) in aqueous solution. Such cross-links can reform after the fluid has been subjected to shear.
一种可用于地下井筒的粘化
水溶液是在
水溶液中通过以下反应制成的:(i) 高分子链上带有
羧酸或
氨基的初始聚合物;(ii) 带有
氨基或
羧酸基团的第二种化合物;(iii)
偶联剂、(iii)
偶联剂,使第二种化合物的分子通过酰胺基团与聚合物链连接,从而形成改性聚合物的
水溶液。第二种化合物可包括疏
水基团,从而使改性聚合物含有疏
水基团,并能在
水溶液中通过疏
水基团的结合(不形成共价键)与自身或粘弹性表面活性剂交联。这种交联可在流体受到剪切力后重新形成。