Abstract: For use in hydraulic workover operations for oil and gas wells, a snubbing element is provided that is made entirely of polymeric material such as polyurethane. According to a preferred embodiment of the invention, the strength and rigidity supplied to the snubbing element in the prior art metallic support ring is now provided by molding that portion of the polymeric annular snubbing element from a polymeric material having a higher density and hardness than that of the polymeric sealing member. The polymeric annular snubbing element thus comprises a high density polymeric support member and a relatively lower density polymeric sealing member.

Abstract: A rubber composition for use in annular packer elements for blowout preventers is provided which comprises from about 45 to about 55 weight percent of an acrylonitrile-butadiene copolymer; from about 10 to about 15 weight percent of a first admixture further comprising a major amount of colloidal silica and minor effective amounts of coupling agent, curative, lubricant, dispersant, activator and antiscorching agent; from about 30 to about 40 weight percent of a second admixture further comprising a major amount of carbon black and minor effective amounts of a plasticizer, antioxidant and antiozonant; and minor effective amounts of tetraethyl thiuram disulfide and benzothiazyl disulfide.

Abstract: Reinforced polymer compositions comprising a minor effective amount of a particulate metal reinforcing agent are provided. A preferred particulate metal reinforcing agent preferably comprises a plurality of discrete particles, each further comprising nickel, chromium and titanium carbide. Polymer compositions adapted to undergo a color change when subjected to a particular thermal history for a particular time interval are also provided.