Polymers are provided that offer gas hydrate inhibition, salt tolerance, and high cloud point. The polymers are polymerized from at least (A) 50 mole percent or more of a monomer selected from the group consisting of: N-vinyl-2-caprolactam, one of its analogues, and combinations thereof, (B) an alkenyl sulfonic acid monomer, salt thereof, or combinations thereof, and (C) an TV-vinyl amide, a (meth)acrylamide or one of its analogues, or combinations thereof. In one embodiment, the (A) monomer is N-vinyl-2-caprolactam, the (B) monomer is 2-acrylamido-2-methylpropane sulfonic acid or salt thereof, and the (C) monomer is N-vinyl-2-pyrrolidone, acrylamide, methacrylamide, or combinations thereof.