Reverse sliding seal for expandable tubular connections

Abstract

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. Because the point of contact between the rib and the groove is a relatively small area, the force acting on the point of contact generates a high bearing pressure that is equal to or greater than the internal pressure within the expandable tubulars and, thus, generates a high pressure seal.

1 . An expandable threaded tubular connection comprising:
 a first tubular segment with a pin member, the pin member including interengageable thread means, a pin nose and a groove formed in the pin nose;   a second tubular segment with a box member, the box member including interengageable thread means suitable for threadedly engaging the pin member and a rib designed to rest within the groove in the pin nose when the threaded tubular connection is made up;   wherein the groove in the pin member is sized to allow the rib to move within the groove as a result of axial movement of the pin nose during radial expansion of the threaded tubular connection.   
     
     
         2 . The expandable threaded tubular connection of  claim 1  wherein the pin nose moves axially away from the back of the box member during radial expansion of the threaded tubular connection. 
     
     
         3 . The expandable threaded tubular connection of  claim 2  wherein the axial movement of the pin nose causes the rib to move within the groove in the pin member until a portion of the rib contacts a portion of the groove. 
     
     
         4 . The expandable threaded tubular connection of  claim 3  wherein the contact between the rib and the groove creates a seal between the pin member and the box member. 
     
     
         5 . The expandable threaded tubular connection of  claim 1  wherein the rib includes an angled wall forming an end of the rib. 
     
     
         6 . The expandable threaded tubular connection of  claim 5  wherein the groove in the pin member includes an angled wall designed to mate with the angled wall of the rib. 
     
     
         7 . The expandable threaded tubular connection of  claim 6  wherein the angled wall of the rib and the angled wall of the groove are in contact with each other upon the axial movement of the pin nose. 
     
     
         8 . The expandable threaded tubular connection of  claim 7  wherein the pin nose is forced outwardly when the angled wall of the rib and the angled wall of the groove are in contact with each other upon the axial movement of the pin nose. 
     
     
         9 . The expandable threaded tubular connection of  claim 7  wherein the contact between the angled wall of the rib and the angled wall of the groove creates a seal between the pin member and the box member. 
     
     
         10 . The expandable threaded tubular connection of  claim 1  further comprising a sealing element located at the back of the box member. 
     
     
         11 . The expandable threaded tubular connection of  claim 10  wherein the sealing element is made from an elastomeric material. 
     
     
         12 . The expandable threaded tubular connection of  claim 10  wherein the sealing element expands when contacted by a fluid. 
     
     
         13 . The expandable threaded tubular connection of  claim 1  further comprising a sealing element housed within a groove formed in the box member between individual threads of the interengageable thread means of the box member. 
     
     
         14 . The expandable threaded tubular connection of  claim 1  further comprising a sealing element housed within a groove formed in the pin member between individual threads of the interengageable thread means of the pin member. 
     
     
         15 . The expandable threaded tubular connection of  claim 1  wherein a leading edge of the groove in the pin nose is in contact with a back edge of the rib of the box member upon makeup of the threaded tubular connection such that the contact creates a metal-to-metal seal when the threaded tubular connection is madeup. 
     
     
         16 . A method of sealing a threaded connection for expandable tubulars upon radial expansion of the threaded connection comprising:
 providing a pin member on a first tubular segment, the pin member including interengageable thread means, a pin nose, and a groove in the pin nose;   providing a box member in a second tubular segment, the box member including interengageable thread means suitable for threadedly engaging the pin member and a rib designed to rest within the groove in the pin nose when the threaded tubular connection is made up;   inserting the pin member of the first tubular segment into the box member of the second tubular segment and threadably connecting the first tubular and the second tubular together;   radially expanding the threaded connection between the first tubular and the second tubular, whereby the pin nose moves axially away from the back of the box member during the radial expansion of the threaded connection;   causing the rib to move within the groove until a portion of the rib contacts a portion of the groove to form a seal between the pin member and the box member.   
     
     
         17 . The method of  claim 16  further comprising providing the rib with an angled wall at an end of the rib. 
     
     
         18 . The method of  claim 17  further comprising providing the groove with an angled wall for mating with the angled wall of the rib. 
     
     
         19 . The method of  claim 18  further comprising causing the angled wall of the rib and the angled wall of the groove to contact each other upon the axial movement of the pin nose. 
     
     
         20 . The method of  claim 19  whereby the contact between the angled wall of the rib and the angled wall of the groove creates a seal between the pin member and the box member. 
     
     
         21 . The method of  claim 16  further comprising providing a sealing element located at the back of the box member. 
     
     
         22 . The method of  claim 21  further comprising contacting the sealing element with a fluid, whereby the sealing element expands in response to contact with the fluid.