Patent ID: 8091930
Filing Date: 2012-01-10
Classification: E21B,F16L

Abstract:
1. A subterranean well tubular connection comprising: a coupling including an inner surface, a first box end and an opposite box end, a pin end of a first tubular member engaged in the first box end of the coupling, a pin end of a second tubular member engaged in the opposite box end of the coupling and a shoulder ring installed between the pin ends, said shoulder ring including a metal tube of a preselected length, with substantially parallel ends, said tube having coupling mating threads on at least part of the outer surface to engage box threads on the inner surface of said coupling, between said pin ends, said tube of such preselected length that each said pin end will engage one of said ends when the assembly of the connection is complete, and wherein said mating threads comprise a shallow, well rounded, thread form arranged to receive the crests of said box threads, vet slip over said box threads when exposed to at least a preselected axial force against said shoulder ring.