Crosslinked polymers derived from monomers having acryloyl and lactam moieties and sulfonic acid/sulfonate comonomers, compositions thereof, and applications thereof

1. An oilfield composition comprising a polymer,

wherein the composition is a cementing fluid, a fracturing fluid, a servicing fluid, a gravel packing mud, a completion fluid, a workover fluid, or a spacer fluid;

wherein said polymer is present in an amount from about 0.01% by weight to about 20% by weight of said composition;

said polymer having repeating units derived from

(a) at least one monomer comprising at least one functionalized or unfunctionalized acryloyl moiety and at least one lactam moiety having a structure selected from the group consisting of:

(b) at least one monomer comprising at least one sulfonic acid moiety or a salt thereof; and

(c) at least one crosslinker,

said oilfield composition further comprising at least one additive selected from the group consisting of secondary fluid loss control agents, secondary cement anti-settling agents, agents for delayed crosslinking, weighting agents, silica flour, strength enhancers, rheology modifiers, friction reducers, dispersing agents, surfactants, clathrate hydrate inhibitors, shale swelling inhibitors, gelation inhibitors, gas migration control additives, set retarding agents, accelerants, activators, defoaming agents, lost circulation materials, corrosion inhibitors, salts, strength retrogression additives, vitrified shale, thixotropic additives, and combinations thereof.