| 摘要 |
The invention relates to aviscosifier useful for oilfield fluids, especially high TDS fluids and heavy brines, comprising : ▪ at least a zwitterionic polymer, prepared by inverse emulsion polymerization of : -monomers A comprising a betaine group; -nonionic monomers B -monomers C including a metal ion crosslinkable group with a molar ratio of the monomers A to the monomers B between 4/96 and 40/60; and ▪ at least a metal ion compound leading to the crosslinking of the groups carried by monomers C. |
