Reverse sliding seal for expandable tubular connections

Abstract From the Canadian patent

An expandable threaded connection between segments of expandable tubulars that provides a high bearing pressure seal at a specific area along the pin and box members is disclosed. The invention utilizes a "groove" in a surface of the box member and a corresponding "rib" on the pin nose. The radial expansion of the tubulars causes the pin to become shorter in length thereby causing the pin nose to retract from the back of the box member. As the pin nose retracts the rib on the pin nose moves backward until a portion of the rib contacts a portion of the groove in the box member. The point of contact between the rib and the groove creates a metal-to-metal seal between the pin and box members. …