Abstract: Metal-to-metal seals for pin and box member tubular joints are disclosed where mating annular surfaces are machined at slightly different angles such that the bearing load from initial contact is entirely on the leading edge of the pin annular surface and the trailing edge of the box annular surface. The mismatch of the sealing surfaces is selected for any particular seal geometry such that at final make-up, the bearing load has a relatively even distribution across the entire sealing surface in contact, thus broadly distributing make-up bearing stresses and minimizing any resulting tendency for galling that may occur, in particular for joints having relatively thick walls for both pin and box members.

Abstract: A tubular connection comprising a pin end and a box end of adjacent joints having a conical metal-to-metal seal located with respect to the pin end forward thread set and its nose, the improvement of a circumferential groove in the pin end forward of the metal-to-metal seal which carries an elastomeric sealing ring radially extending beyond the limits of the groove. The metal-to-metal makeup of the connection causes by conical deformation a slight wedge shape opening to form forward of the metal-to-metal seal. The elastomeric material extrudes to fill this wedge shape opening to thereby form a compound seal forward of the metal-to-metal seal.

Abstract: A threaded pipe connection is disclosed of the wedge-shaped thread type that avoids high stress concentrations in the box between the first thread and the end of the box by making the length of the box between the first thread and the end of the box equal to or greater than 5% of the pipe diameter and by providing clearance between the crest of the first full thread on the box and the root of the last thread on the pin and between the crest of the last full thread on the pin and the root of the first full thread on the box.

Abstract: A pipe joint for use with oil country tubular goods, such as tubing, casing, and drill pipe, a threaded member adapted to be connected to another threaded member to form such a pipe joint, and a method of making the threaded member are disclosed wherein selected mating threads of the joint and selected threads on the member that are adapted to mate with the threads of another threaded member have less clearance between the load flanks of the selected threads and the mating threads than do the other mating threads of the joint and the other threads of the member, when connected to another threaded member, to cause the selected threads to be stressed initially and to more uniformly stress all of the threads of the joint, when the joint is made-up and when additional external loads are applied.

Abstract: A threaded pipe connection is disclosed having tapered sealing surfaces between the ends of the threads on the box and pin that engage and a resilient seal member located in a groove about midway between the ends of one of the surfaces to form a seal with the other surface when the joint is made up with the two surfaces forming independent metal-to-metal seals on both sides of the resilient seal member.

Abstract: A joint and male and female tubular elements are disclosed where the threads of the female and male members have negative load flanks and have two or more radial steps axially separated one from another by a reverse angle torque shoulder having one or two adjacent conical sealing surfaces. The reverse angle torque shoulder serves as a positive assembly stop. The negative load flank angle of the threads and the reverse torque shoulder angle combine to interlock the male and female members and to prevent differential radial separation of the conical sealing surfaces when the joint is exposed to internal pressure, external pressure or both. Tapered threads and sealing surfaces and interference threads may advantageously be used in joint construction.