Damage tolerant casing hanger seal

Abstract

A seal assembly is inserted within an annulus between inner and outer coaxially disposed annular members having a common axis. The seal assembly includes a seal stack having a compliant element sandwiched between two anti-extrusion elements that contain the flow of the compliant element. The seal assembly also includes a sealing ring and a locking ring coupled to the sealing ring. The seal assembly also includes an energizing ring configured to be moved axially in a first direction by a ring tool to apply an axial force to the locking ring, which in turn acts on the sealing ring to radially deform the sealing ring into sealing engagement with the annular members. Continued axial movement of the locking ring in the first direction radially deforms the locking ring into locking engagement with the annular members.

What is claimed is: 
     
         1 . A seal assembly for sealing within an annulus between inner and outer coaxially disposed annular members having a common axis, the seal assembly comprising:
 a first anti-extrusion sealing ring having a chevron shaped geometry;   a second anti-extrusion sealing ring having a chevron shaped geometry, the second anti-extrusion sealing ring coaxial with and axially below the first anti-extrusion sealing ring;   a first compliant sealing ring having a chevron shaped geometry, the first compliant sealing ring coaxial with and interposed between the first anti-extrusion sealing ring and the second anti-extrusion sealing ring;   wherein at least one of the first and second anti-extrusion sealing rings is configured to radially engage at least one of the inner and outer coaxially disposed annular members when subjected to an axial force; and   the first compliant sealing ring is configured to radially engage at least one of the inne and outer coaxially disposed annular members when subjected to an axial force.   
     
     
         2 . The seal assembly of  claim 1 , further comprising:
 a spring axially aligned with the first and second anti-extrusion sealing rings and the compliant sealing ring; and   wherein the spring maintains an axial force on the first and second anti-extrusion sealing ring and the first complaint sealing ring, thereby maintaining a radial force between the sealing rings and the inner and outer annular members.   
     
     
         3 . The seal assembly of  claim 1 , further comprising:
 a third anti-extrusion sealing ring having a chevron shaped geometry, the third anti-extrusion sealing ring coaxial with the first and second anti-extrusion sealing rings;   a fourth anti-extrusion sealing ring having a chevron shaped geometry, the fourth anti-extrusion sealing ring coaxial with the first, second, and third anti-extrusion sealing rings;   a second compliant sealing ring having a chevron shaped geometry, the second compliant sealing ring coaxial with and interposed between the third anti-extrusion sealing ring and the fourth anti-extrusion sealing ring; and   wherein the first and second anti-extrusion sealing rings face in a first axial direction, and the third and fourth anti-extrusion sealing rings face in a second axial direction, opposite the first axial direction, thereby forming a bi-directional seal when energized.   
     
     
         4 . The seal assembly of  claim 1 , wherein the first compliant sealing ring comprises a material having a modulus of elasticity no greater than half of the modulus of elasticity of the first and second anti-extrusion rings. 
     
     
         5 . The seal assembly of  claim 1 , wherein:
 the first and second anti-extrusion sealing rings are formed from materials selected from the group consisting of metals, polymers, elastomers, ceramics, and composites thereof; and   the first compliant sealing ring is formed from materials selected from the group consisting of metals, polymers, elastomers, ceramics, and composites thereof.   
     
     
         6 . The seal assembly of  claim 1 , further comprising:
 an upper activation ring coaxial with and axially above the first anti-extrusion ring, the upper activation ring having a lower mating surface forming an angle to the axis different from the adjacent surface of the first anti-extrusion ring;   a lower activation ring coaxial with and axially below the second anti-extrusion ring, the lower activation ring having an upper mating surface forming an angle to the axis different from the adjacent surface of the second anti-extrusion ring;   wherein mating surfaces between the first anti-extrusion ring and the first compliant ring are at equivalent angles to the axis, allowing the first anti-extrusion ring and the first compliant ring to contact along the length of the mating surfaces;   wherein mating surfaces between the second anti-extrusion ring and the first compliant ring are at equivalent angles to the axis, allowing the second anti-extrusion ring and the first compliant ring to contact along the length of the mating surfaces; and   wherein under axial load, contact between the upper and lower activation ring mating surfaces with adjacent anti-extrusion sealing ring mating surfaces causes radial expansion of the first and second anti-extrusion sealing rings and the compliant sealing ring.   
     
     
         7 . The seal assembly of  claim 6 , wherein the angles of the mating surfaces between the first anti-extrusion sealing ring, the second anti-extrusion ring, and the compliant ring cause an increase in sealing pressure in response to increased pressure within the annulus. 
     
     
         8 . The seal assembly of  claim 1 , further comprising:
 the first anti-extrusion sealing ring having a lower mating surface forming an angle to the axis that is different than an angle formed by a mating surface of the adjacent compliant sealing ring to the axis;   the second anti-extrusion sealing ring having an upper mating surface forming an angle to the axis that is different than an angle formed by a mating surface of the adjacent compliant sealing ring to the axis; and   wherein under axial load, contact between the mating surfaces causes radial expansion of the first and second anti-extrusion sealing rings and the compliant sealing ring.   
     
     
         9 . The seal assembly of  claim 8 , wherein at least one of the angles of the first anti-extrusion sealing ring mating surface and the second anti-extrusion ring surface causes an increase in sealing pressure in response to increased pressure within the annulus. 
     
     
         10 . The seal assembly of  claim 1 , further comprising:
 a third anti-extrusion sealing ring having a chevron shaped geometry, the third anti-extrusion sealing ring coaxial with the first and second anti-extrusion sealing rings;   a fourth anti-extrusion sealing ring having a chevron shaped geometry, the fourth anti-extrusion sealing ring coaxial with the first, second, and third anti-extrusion sealing rings, and axially below the third anti-extrusion sealing ring;   a second compliant sealing ring having a chevron shaped geometry, the compliant sealing ring coaxial with and interposed between the third anti-extrusion sealing ring and the fourth anti-extrusion sealing ring;   wherein the third and fourth anti-extrusion sealing rings have an outer diameter smaller than an inner diameter of the first and second anti-extrusion sealing rings;   wherein outer diameter surfaces of at least one of the first and second anti-extrusion sealing rings seal to the outer annular member when energized;   wherein outer diameter surfaces of the first compliant sealing ring seal to the outer annular member when energized;   wherein inner diameter surfaces of at least one of the third and fourth anti-extrusion sealing rings seal to the inner annular member when energized; and   wherein inner diameter surfaces of the second compliant sealing ring seal to the inner annular member when energized.   
     
     
         11 . The seal assembly of  claim 10 , the seal assembly further comprising:
 a seal retainer ring comprising an annular member defining inner and outer annular upward facing shoulders separated by a cylindrical member coaxial with the axis;   wherein the seal retainer ring removably couples to a running tool for insertion of and removal of the seal assembly;   wherein the first and second anti-extrusion sealing rings and the first compliant sealing ring mount to the outer upward facing shoulder of the seal retainer ring; and   wherein the third and fourth anti-extrusion sealing rings and the second compliant ring mount to the inner upward facing shoulder of the seal retainer ring.   
     
     
         12 . A seal assembly for sealing within an annulus between inner and outer coaxially disposed annular members having a common axis, the seal assembly comprising:
 a seal stack;   an upper activation ring coaxial with and axially above the seal stack, the upper activation ring having a lower mating surface forming an angle to the axis different from the adjacent surface of the seal stack;   a lower activation ring coaxial with and axially below the seal stack, the lower activation ring having an upper mating surface forming an angle to the axis different from the adjacent surface of the seal stack;   wherein mating surfaces between elements of the seal stack are at equivalent angles to the axis, allowing the elements to contact the along the length of the mating surfaces; and   wherein under axial load contact between the upper and lower activation ring mating surfaces with adjacent seal stack mating surfaces causes radial expansion of the seal stack.   
     
     
         13 . The seal assembly of  claim 12 , further comprising:
 a spring axially aligned with the seal stack; and   wherein the spring maintains an axial force on the seal stack, thereby maintaining a radial force between the seal stack and the inner and outer annular members.   
     
     
         14 . The seal assembly of  claim 12 , wherein the seal stack comprises:
 a first anti-extrusion sealing ring having a chevron shaped geometry;   a second anti-extrusion sealing ring having a chevron shaped geometry, the second anti-extrusion sealing ring coaxial with and axially below the first anti-extrusion sealing ring;   a first compliant sealing ring having a chevron shaped geometry, the first compliant sealing ring coaxial with and interposed between the first anti-extrusion sealing ring and the second anti-extrusion sealing ring;   wherein at least one of the first and second anti-extrusion sealing rings is configured to radially engage at least one of the inner and outer coaxially disposed annular members when subjected to an axial force; and   the first compliant sealing ring is configured to radially engage at least one of the inner and outer coaxially disposed annular, members when subjected to an axial force.   
     
     
         15 . The seal assembly of  claim 14 , wherein the seal stack further comprises:
 a third anti-extrusion sealing ring having a chevron shaped geometry, the third anti-extrusion sealing ring coaxial with the first and second anti-extrusion sealing rings;   a fourth anti-extrusion sealing ring having a chevron shaped geometry, the fourth anti-extrusion sealing ring coaxial with the first, second, and third anti-extrusion sealing rings, and axially below the third anti-extrusion sealing ring;   a second compliant sealing ring having a chevron shaped geometry, the second compliant sealing ring coaxial with and interposed between the third anti-extrusion sealing ring and the fourth anti-extrusion sealing ring; and   wherein the first and second anti-extrusion sealing rings face in a first axial direction, and the third and fourth anti-extrusion sealing rings face in a second axial direction, opposite the first axial direction, thereby forming a bi-directional seal when energized.   
     
     
         16 . The seal assembly of  claim 14 , wherein the first compliant sealing ring comprises a material having a modulus of elasticity no greater than half of the modulus of elasticity of the first and second anti-extrusion rings. 
     
     
         17 . The seal assembly of  claim 14 , wherein:
 the first and second anti-extrusion sealing rings are formed from materials selected from the group consisting of metals, polymers, elastomers, ceramics, and composites thereof; and   the first compliant sealing ring is formed from materials selected from the group consisting of metals, polymers, elastomers, ceramics, and composites thereof.   
     
     
         18 . The seal assembly of  claim 14 , further comprising:
 a third anti-extrusion sealing ring having a chevron shaped geometry, the third anti-extrusion sealing ring coaxial with the first and second anti-extrusion sealing rings;   a fourth anti-extrusion sealing ring having a chevron shaped geometry, the fourth anti-extrusion sealing ring coaxial with the first, second, and third anti-extrusion sealing rings, and axially below the third anti-extrusion sealing ring;   a second compliant sealing ring having a chevron shaped geometry, the second compliant sealing ring coaxial with and interposed between the third anti-extrusion sealing ring and the fourth anti-extrusion sealing ring;   wherein the third and fourth anti-extrusion sealing rings have an outer diameter smaller than an inner diameter of the first and second anti-extrusion sealing rings;   wherein outer diameter surfaces of at least one of the first and second anti-extrusion sealing rings seal to the outer annular member when energized;   wherein outer diameter surfaces of the first compliant sealing ring seal to the outer annular member when energized;   wherein inner diameter surfaces of at least one of the third and fourth anti-extrusion sealing rings seal to the inner annular member when energized; and   wherein inner diameter surfaces of the second compliant sealing ring seal to the inner annular member when energized.   
     
     
         19 . The seal assembly of  claim 18 , the seal assembly further comprising:
 a seal retainer ring comprising an annular member defining inner and outer annular upward facing shoulders separated by a cylindrical member coaxial with the axis;   wherein the seal retainer ring removably couples to, a running tool for insertion of and removal of the seal assembly;   wherein the first and second anti-extrusion sealing rings and the first compliant sealing ring mount to the outer upward facing shoulder of the seal retainer ring; and   wherein the third and fourth anti-extrusion sealing rings and the second compliant ring mount to the inner upward facing shoulder of the seal retainer ring.   
     
     
         20 . A seal assembly for sealing within an annulus between inner and outer coaxially disposed annular members having a common axis, the seal assembly comprising:
 a first seal stack having an inner diameter;   the first seal stack having compliant sealing elements that, when energized, seal to a damaged surface of the outer annular member;   a second seal stack coaxial with the first seal stack, the second seal stack having an outer diameter smaller than the inner diameter of the first seal stack; and   the second seal stack having compliant sealing elements that, when energized, seal to a damaged surface of the inner annular member.   
     
     
         21 . The seal assembly of  claim 20 , the seal assembly further comprising:
 a seal retainer ring comprising an annular member defining inner and outer annular upward facing shoulders separated by a cylindrical member coaxial with the axis;   wherein the seal retainer ring removably couples to a running tool for insertion and removal of the first and second seal stack;   wherein the first seal stack mounts to the outer upward facing shoulder of the seal retainer ring; and   wherein second seal stack mounts to the inner upward facing shoulder of the seal retainer ring.   
     
     
         22 . The seal assembly of  claim 20 , wherein the first and second seal stacks each comprise:
 a first anti-extrusion sealing ring having a chevron shaped geometry;   a second anti-extrusion sealing ring having a chevron shaped geometry, the second anti-extrusion sealing ring coaxial with and axially below the first anti-extrusion sealing ring;   a first compliant sealing ring having a chevron shaped geometry, the first compliant sealing ring coaxial with and interposed between the first anti-extrusion sealing ring and the second anti-extrusion sealing ring;   wherein at least one of the first and second anti-extrusion sealing rings is configured to radially engage at least one of the inner and outer coaxially disposed annular members when subjected to an axial force; and   the first compliant sealing ring is configured to radially engage at least one of the inner and outer coaxially disposed annular members when subjected to an axial force.   
     
     
         23 . The seal assembly of  claim 22 , wherein the compliant sealing ring comprises a material having a modulus of elasticity no greater than half of the modulus of elasticity of the first and second anti-extrusion rings. 
     
     
         24 . The seal assembly of  claim 22 , wherein:
 the first and second anti-extrusion sealing rings are formed from materials selected from the group consisting of metals, polymers, elastomers, ceramics, and composites thereof; and   the compliant sealing ring is formed from materials selected from the group consisting of metals, polymers, elastomers, ceramics, and composites thereof.   
     
     
         25 . The seal assembly of  claim 22 , wherein the first and second seal stacks each further comprise:
 a third anti-extrusion sealing ring having a chevron shaped geometry, the third anti-extrusion sealing ring coaxial with the first and second anti-extrusion sealing rings;   a fourth anti-extrusion sealing ring having a chevron shaped geometry, the fourth anti-extrusion sealing ring coaxial with the first, second, and third anti-extrusion sealing rings;   a second compliant sealing ring having a chevron shaped geometry, the second compliant sealing ring coaxial with and interposed between the third anti-extrusion sealing ring and the fourth anti-extrusion sealing ring; and   wherein the first and second anti-extrusion sealing rings face in a first axial direction, and the third and fourth anti-extrusion sealing rings face in a second axial direction, opposite the first axial direction, thereby forming a bi-directional seal when energized.   
     
     
         26 . The seal assembly of  claim 20 , further comprising:
 a spring axially aligned with the first and second seal stacks; and   wherein the spring maintains an axial force on the first and second seal stacks, thereby maintaining a radial force between the first and second seal stacks and the inner and outer annular members.   
     
     
         27 . A method for sealing within an annulus between inner and outer coaxially disposed annular members having a common axis, the method comprising:
 (a) providing a sealing ring;   (b) coupling a locking ring to the sealing ring;   (c) axially moving an energizing ring in a first direction with a setting tool to apply an axial force to the locking ring, which in turn acts on the sealing ring to radially deform the sealing ring into sealing engagement with the annular members; and   (d) continuing axial movement of the locking ring in the first direction to radially deform the locking ring into locking engagement with the annular members.   
     
     
         28 . The method of  claim 27 , wherein step (b) comprises applying an axial force to the sealing ring. 
     
     
         29 . The method of  claim 27 , wherein step (b) comprises placing the sealing ring on an upward facing surface in a seal pocket between the inner and outer members after the locking ring is coupled to the sealing ring and before step (c).