ЦВИТТЕРИОННЫЕ ПОЛИМЕРЫ, СОДЕРЖАЩИЕ ЗВЕНЬЯ ТИПА БЕТАИНА И ПРИМЕНЕНИЕ ЦВИТТЕРИОННЫХ ПОЛИМЕРОВ В ПРОМЫВОЧНОЙ ЖИДКОСТИ

摘要

Polymers comprising at least 35 mole% betaine-functional units are used as clay swelling inhibitors and/or fluid loss additives in drilling fluids. Independent claims are also included for: (1) zwitterionic polymers comprising alkoxylated units of formula (I) and at least 35 mole% betaine-functional units; (2) drilling fluid containing a zwitterionic polymer as above. CH 2CHR 6>(X 2>(CH 2CH 2O) nR 7>) (I) R 6>H or Me; X 2>COO, CONH or C 6H 4CH 2; n : 1 or more; R 7>H, alkyl or tristyrylphenyl.