An additive for water-base drilling fluid compositions used for drilling subterranean wells is disclosed. In one embodiment, the additive is a sulfonated copolymer of recurring units of a maleimide monomer and recurring units of a vinyl monomer. In another embodiment, the additive is a sulfonated terpolymer of recurring units of a maleimide monomer, recurring units of a vinyl monomer, and recurring units of a carboxyl-containing monomer. Water-base drilling fluids compositions which contain the additive and a process for drilling subterranean wells therewith are also disclosed.
本发明公开了一种用于钻探地下井的
水基钻井液组合物的添加剂。 在一个实施例中,该添加剂是马来
酰亚胺单体重复单元和
乙烯基单体重复单元的磺化共聚物。 在另一个实施例中,该添加剂是马来
酰亚胺单体重复单元、
乙烯基单体重复单元和含羧基单体重复单元的磺化三元共聚物。 本发明还公开了含有该添加剂的
水基钻井液组合物以及使用该添加剂钻探地下井的工艺。