Stabilized center-shoulder-sealed tubular connection

The present invention pertains to a tubular connection having a stabilized center-shoulder seal. The stabilization of the center-shoulder seal is achieved using at least one run-out section of thread adjacent to the center-shoulder seal configuration of each connection member. Typically, the at least one run-out section of thread is located adjacent the side of the center-shoulder at which the connection member wall thickness is less. The run-out section of thread is typically used in combination with a run-in section of thread on the corresponding connection member. Preferably, the center shoulder seal configuration of each connection member is positioned between a run-out thread section and a run-in thread section. (The corresponding connection member will also comprise the corresponding sections of run-in and run-out threads, respectively, so there is a set of run-in and run-out threads). Even more preferably, in addition to the connection having one set of run-out and run-in thread sections adjacent to the center-shoulder seal, the connection has a second set of run-out and run-in threads adjacent to the exterior edges of the connection (A double run-out, run-in stabilization of the center-shoulder seal). The double set of run-out, run-in sections of thread provides the most stable connection. The most preferred center-shoulder seal design is a "locked double shoulder" design, wherein the cross section of the assembled center-shoulder area exhibits an interlocking double shoulder configuration.