Casing Patch and Seal

Abstract

A casing patch assembly may include a patch seal having two ring-type seals with different performance characteristics. A first ring seals against a casing patch and a casing stub. A second ring self-adjusts to the size of the casing stub and is located so that it blocks the first seal, which may be softer material than the second ring, from being squeezed into an annular gap between the casing patch and the casing stub. The second ring may include a split feature to allow for the self-adjustment. Optionally, a third ring made of a malleable material may be located between the first and second rings to protect the first ring from being damaged by movement of the split feature.

1 . A casing patch seal comprising:
 a first part adapted to provide a seal between an inner tube and an outer tube surrounding the inner tube; and   a second part adapted to cover a circular gap between the inner tube and a constricted portion of the outer tube and to prevent the first part from entering the gap.   
     
     
         2 . The seal of  claim 1 , wherein the first part is formed of a softer material than that of the second part. 
     
     
         3 . The seal of  claim 1 , wherein the first part is configured to expand after replacement of the inner tube with another inner tube having an outer diameter that is less than that of the replaced inner tube. 
     
     
         4 . The seal of  claim 1 , wherein the first part includes an inner sealing surface defining a seal diameter, the sealing surface adapted to seal around the inner tube, and wherein the first part is formed of a resilient material that allows the seal diameter to change in size. 
     
     
         5 . The seal of  claim 1 , wherein the first part is a ring including an inner surface for contacting the inner tube and an outer surface for contacting the outer tube, and wherein the inner and outer surfaces are adapted to move apart from each other to maintain sealing function after replacement of the inner tube with another inner tube having an outer diameter that is less than that of the replaced inner tube. 
     
     
         6 . The seal of  claim 1 , wherein the second part is formed of a metal. 
     
     
         7 . The seal of  claim 1 , wherein the second part is configured to contract in circumference after replacement of the inner tube with another inner tube having an outer diameter that is less than that of the replaced inner tube. 
     
     
         8 . The seal of  claim 1 , wherein the second part includes an inner contact surface defining a contact diameter, and a cut extends through the second part to allow the contact diameter to change in size. 
     
     
         9 . The seal of  claim 1 , wherein the second part is a ring including two opposing ends adapted to move relative to each other to allow the ring to change in circumference. 
     
     
         10 . The seal of  claim 9 , wherein the ends include tapered portions of the ring. 
     
     
         11 . The seal of  claim 9 , wherein the ends overlap each other. 
     
     
         12 . The seal of  claim 1 , further comprising a third part disposed between the first and second parts. 
     
     
         13 . The seal of  claim 12 , wherein the third part is formed of a material softer than that of the second part to allow the third part to at least partially conform to an adjacent surface feature of the second part. 
     
     
         14 . The seal of  claim 12 , wherein the third part is formed of a material harder than that of the first part. 
     
     
         15 . The seal of  claim 12 , wherein the third part is formed of a material including lead. 
     
     
         16 . A casing patch seal comprising:
 a first ring adapted to maintain sealing contact with an outer tube and a first inner tube inside the outer tube; and   a second ring adapted to block the first ring from moving axially into a gap between the first inner tube and the outer tube.   
     
     
         17 . The seal of  claim 16 , wherein the second ring is configured to change in circumference after replacement of the first inner tube with a second inner tube having a different diameter than the first inner tube. 
     
     
         18 . The seal of  claim 16 , further comprising a lead ring disposed between the first and second rings, the lead ring having a hardness greater than that of the first ring and lower than that of the second ring. 
     
     
         19 . The seal of  claim 16 , further comprising a third ring disposed adjacent to the second ring, the third ring adapted to deform against the second ring. 
     
     
         20 . The seal of  claim 16 , wherein the second ring is a split ring. 
     
     
         21 . The seal of  claim 20 , wherein the split ring includes end portions that overlap each other. 
     
     
         22 . The seal of  claim 20 , wherein a split in the split ring is at an oblique angle to the central axis of the split ring. 
     
     
         23 . The seal of  claim 20 , further comprising a third ring disposed immediately adjacent to the split ring and adapted to deform at opposing ends of the spit ring. 
     
     
         24 . A casing patch seal comprising:
 a seal ring adapted to seal a casing stub to a casing patch bowl; and   a non-extrusion ring adapted to block the seal ring from moving axially into a gap between the casing stub and the casing patch bowl.   
     
     
         25 . The seal of  claim 24 , further including a protector ring disposed between the seal ring and the non-extrusion ring, the protector ring adapted to at least partially conform to an adjacent edge of the non-extrusion ring. 
     
     
         26 . The seal of  claim 24 , wherein the non-extrusion ring includes a contact surface movable from a first configuration for facing a protector sleeve to a second configuration for facing the casing stub. 
     
     
         27 . The seal of  claim 26 , wherein the contact surface has a diameter when in the first configuration that is smaller than when in the second configuration. 
     
     
         28 . The seal of  claim 26 , wherein the contact surfaces includes a circular edge, the circular edge being substantially planar when the contact surface is in the first configuration and substantially non-planar when the contact surface is in the second configuration. 
     
     
         29 . The seal of  claim 28 , further comprising a protector ring adjacent to the circular edge, the protector ring adapted to at least partially conform to the circular edge. 
     
     
         30 . The seal of  claim 24 , wherein the non-extrusion ring includes a split feature and two ends at the split feature, the two ends adapted to move relative to each other to allow the non-extrusion ring to change in circumference. 
     
     
         31 . The seal of  claim 30 , further including a protector ring adjacent to the non-extrusion ring, the protector ring adapted to deform after the relative movement of the two ends of the non-extrusion ring. 
     
     
         32 . A casing patch assembly comprising:
 a casing patch;   a protector sleeve axially movable relative to the casing patch; and   a seal disposed between the casing patch and the protector sleeve, the seal including a seal ring and a blocking ring adapted to block movement of the seal ring in an axial direction relative to the casing patch.   
     
     
         33 . The assembly of  claim 32 , wherein the protector sleeve is axially movable relative the seal to allow placement of a casing stub adjacent to the seal. 
     
     
         34 . The assembly of  claim 33 , wherein the blocking ring is adapted to change in circumference after placement of the casing stub adjacent to the seal. 
     
     
         35 . The assembly of  claim 32 , wherein the seal further includes a protector ring disposed between the seal ring and the blocking ring, the protector ring adapted to deform after a change in shape of the blocking ring. 
     
     
         36 . A method of sealing a casing patch to a casing stub, the method comprising:
 sealing the casing patch to a casing stub with a sealing ring; and   covering a gap between the casing patch and the casing stub with a blocking ring that blocks a sealing ring from moving into the gap.   
     
     
         37 . The method of  claim 36 , further comprising allowing or inducing a change in shape of the blocking ring. 
     
     
         38 . The method of  claim 37 , further comprising protecting the sealing ring from damage after the change in shape. 
     
     
         39 . The method of  claim 36 , further comprising:
 replacing a protector sleeve disposed adjacent to the sealing ring with the casing stub; and   after the replacement of the protector sleeve, allowing or inducing the blocking ring to change in circumference in accordance with a circumference of the casing stub.   
     
     
         40 . The method of  claim 39 , further comprising allowing or inducing a protector ring disposed between the sealing ring and blocking ring to deform after the change in circumference of the blocking ring.