Compositions and applications thereof of water-soluble copolymers comprising an ampholytic imidazolium inner salt

摘要

Polymer compositions and their applications in hostile environments for oil field operations are disclosed. The compositions contains a polymer which is copolymerized by (a) an ampholytic monomer having the formula of: ##STR1## where one and only one of the substituted groups R. sub.1, R.sub.2, R.sub.3 and R.sub.4 must be a vinyl group, the rest can be the same or different and can be hydrogen or a C. sub.1 -C. sub.3 alkyl group; R.sub.5 is a phenyl group; n is ≧1 and ≦6; and q is 0 or 1; (b) at least one comonomer having an ethylenic linkage. The compositions further contain crosslinking agents, such as phenol and formaldehyde, for reducing permeability in a high temperature subterranean formation; and water for use in well treating fluids.