Abstract: A threaded pipe connection is shown which features a pressure energized flex-seal structure. The connection includes a first box member having a box end, the box end having an end opening defining an interior surface with internal threads, the internal threads being defined by crests and roots and opposing flanks. A second, mating pin member has a pin end with a pin nose, the pin end having an exterior surface with mating external threads, the external threads also having crests and roots and opposing flanks, at least selected ones of which move into engagement with the internal threads of the box when the connection is made up. A flex-seal region is located on either the box and interior surface or the pin end which forms a primary containment seal upon make up of the connection.

Abstract: A coil tubing or jointed dual wall drill string assembly for subsurface drilling. The drill string assembly includes a metallic outer tube having an outer tube first end and an outer tube second end opposite the outer tube first end. The assembly also includes a flexible, substantially non-metallic inner tube that is substantially enclosed within and generally coaxially aligned with the outer tube. The flexible, substantially non-metallic inner tube has an inner tube first end, an inner tube second end opposite the inner tube first end, and an inner tube inner diameter. The inner tube and the outer tube define an annular channel therebetween. The drill string assembly also includes a means for conveying fluid through the annular channel toward the inner tube first end. The annular channel is adapted to convey drilling fluid under pressure toward the inner tube first end and the inner tube is adapted to convey cuttings toward the inner tube second end.

Abstract: A dual wall drill string assembly for subsurface drilling. The drill string assembly includes a metallic outer tube having an outer tube first end and an outer tube second end opposite the outer tube first end. The assembly also includes a flexible, substantially non-metallic inner tube that is substantially enclosed within and generally coaxially aligned with the outer tube. The flexible, substantially non-metallic inner tube has an inner tube first end, an inner tube second end opposite the inner tube first end, and an inner tube inner diameter. The inner tube and the outer tube define an annular channel therebetween. The drill string assembly also includes a means for conveying fluid through the annular channel toward the inner tube first end. The annular channel is adapted to convey drilling fluid under pressure toward the inner tube first end, and the inner tube is adapted to convey cuttings toward the inner tube second end.

Abstract: A threaded pin and box connection having thread geometries and/or dissimilar thread fits that prevent the pin thread of a connection from hanging up in the box thread as the pin is being stabbed into or destabbed from the box. Dissimilar geometries and/or threads include dissimilar thread types, dissimilar leads, overlapping leads, thread tooth widths of one component greater than thread grooves of the other component, multiple start threads, and combinations thereof.

Abstract: A threaded pipe connection is shown which features a cylindrical metal-to-metal containment seal. In addition to the cylindrical sealing surfaces, the connection utilizes a separate ramp or ramp regions that simulate a pin swaging or a box expansion which results in the ability of the cylindrical components of the seal to assemble without interference or with only slight interference.