Abstract: The tubular connection includes a pin member having external tapered threads extending from a pin nose to a pin base and a box member having internal tapered threads extending from a box base to a box nose. The tapered threads are square or near square threads having stab and load flanks with accommodating grooves. The stab flanks have corner chamfers which engage upon stabbing the pin member into the box member. The comer chamfers increase the clearances between the threads and grooves and guide the crests to the root openings upon relative rotation of the pin and box members. The stab flanks may have an increased thread width at the thread pitch line forming cam flanks which cam the threads into the grooves. The crests and roots of the threads interferingly engage. The pin nose and box base engage to form a metal-to-metal seal and a primary torque shoulder which during power tight make-up causes the load to shift from the stab flanks to the load flanks.

Abstract: The metal-to-metal sealing system includes a first seal configuration on one member of the connection and a second seal configuration on the other member. Each seal configuration includes an annular groove and an adjacent annular tooth. The annular groove and annular tooth form three frustoconical surfaces with the groove having an annular undercut surface and the annular tooth having an annular shoulder surface. A seal cylindrical surface and a pre-ramp cylindrical surface extend from the mouth of the groove and a frustoconical ramp forms the transition surface between the seal and pre-ramp cylindrical surfaces. Further, at the base of the outer side of the annular tooth, there extends a cylindrical surface along the main body of the member. Upon makeup of the connection, the ramps and seal cylindrical surfaces guide and align the seal configurations. Initially the center frustoconical surfaces interferingly engage.

Abstract: The metal-to-metal sealing system includes a first seal configuration on one member of the connection and a second seal configuration on the other member. Each seal configuration includes an annular groove and an adjacent annular tooth. The annular groove and annular tooth form three frustoconical surfaces with the groove having an annular undercut surface and the annular tooth having an annular shoulder surface. A seal cylindrical surface and a pre-ramp cylindrical surface extend from the mouth of the groove and a frustoconical ramp forms the transition surface between the seal and pre-ramp cylindrical surfaces. Further, at the base of the outer side of the annular tooth, there extends a cylindrical surface along the main body of the member. Upon makeup of the connection, the ramps and seal cylindrical surfaces guide and align the seal configurations. Initially the center frustoconical surfaces interferingly engage.

Abstract: 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. 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 comprise the corresponding sections of run-in and run-out threads, respectively, so there is an interengaging set of run-in and run-out threads).

Abstract: 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).

Abstract: The present invention pertains to an improvement in buttress-threaded tubular connections. In particular, the connection is improved by controlling the tubular member thread pitch diameter tolerance to .+-.0.0015 inch, to provide a thread bearing contact pressure which is relatively constant over the entire length of the connection. In addition, the improved connection provides a reduction in hoop stress of about 20% over known buttress-threaded tubing connections.The present invention typically includes the use of variable make-up in combination with the control of the tubular member thread pitch diameter tolerance.