Hard Stop Energizing Ring

Abstract

A wellhead seal assembly that forms a metal-to-metal seal between inner and outer wellhead members. A metal seal ring has inner and outer legs separated by a slot. An extension of seal ring contacts an upward facing shoulder of the inner wellhead member. An energizing ring with a tapered nose is moved into the slot. The tapered nose has a downward facing stop shoulder that contacts an upper end of inner leg when the energizing ring is in its lower position.

What is claimed is: 
     
         1 . A metal-to-metal seal assembly for sealing in a seal pocket between inner and outer tubular members of a wellhead assembly, comprising:
 a seal ring having an axis, and annular inner and outer legs separated from each other by an annular slot having a run-in radial width;   an annular energizing ring having a nose portion with a radial thickness greater than the run-in radial width of the seal ring, and carried in a run-in position with a nose end at an entrance of the annular slot;   an annular stop shoulder on the energizing ring above the nose end;   the seal ring being energized from the run-in position to a set position by applying an axial energizing force to the energizing ring, so that the energizing ring is pressed into the annular slot causing radial plastic deformation of the annular inner and outer legs of the seal ring into sealing contact with the inner and outer tubular members defining the set position; and   the annular stop shoulder contacting an upper end of one of the legs of the seal ring while in the set position.   
     
     
         2 . The assembly according to  claim 1 , further comprising:
 a set of wickers formed in at least one of the seal surfaces, a smooth cylindrical surface adjoining the set of wickers; and   opposing seal surfaces in the bore and on an exterior portion of the inner wellhead member.   
     
     
         3 . The assembly according to  claim 1 , wherein the stop shoulder is perpendicular to the axis. 
     
     
         4 . The assembly according to  claim 1 , wherein the length of the energizing ring below the stop shoulder to the nose end is less than the length of the slot in the seal ring. 
     
     
         5 . The assembly according to  claim 1 , wherein continued axial energy forces applied to the energizing ring after reaching the set point is directed through the stop shoulder to the seal ring. 
     
     
         6 . The assembly according to  claim 1 , wherein the stop shoulder engages the upper end of the inner leg of the seal ring. 
     
     
         7 . The assembly according to  claim 1 , wherein a radial thickness of the energizing ring at the stop shoulder is greater than the radial thickness of the nose part. 
     
     
         8 . The assembly according to  claim 1 , wherein the stop shoulder is located between the nose and an upper end of the energizing ring. 
     
     
         9 . The assembly according to  claim 1 , wherein the nose end is spaced above a base of the slot while the stop shoulder is contacting the upper end of said one of the inner and outer seal legs. 
     
     
         10 . A wellhead assembly with an axis, comprising:
 an outer wellhead member having a bore;   an inner wellhead member in the bore;   an annular space between the inner and outer wellhead members;   a seal member having inner and outer annular legs defining a slot therebetween, the inner leg having an upper end at a lower elevation than an upper end of the outer leg;   an annular energizing ring in the slot and having an annular stop shoulder extending radially inward from the inner surface of the energizing ring positioned in abutment with the upper end of the inner leg of the seal member while the energizing ring is in a set position, preventing further downward movement of the energizing ring in the slot once the energizing ring reaches the set position.   
     
     
         11 . The assembly according to  claim 10 , further comprising:
 a set of wickers formed in at least one of the seal surfaces, a smooth cylindrical surface adjoining the set of wickers; and   opposing seal surfaces in the bore and on an exterior portion of the inner wellhead member.   
     
     
         12 . The assembly according to  claim 10 , wherein the stop shoulder is perpendicular to the axis. 
     
     
         13 . The assembly according to  claim 10 , wherein the length of the energizing ring below the stop shoulder to the nose end is less than the length of the slot in the seal ring. 
     
     
         14 . The assembly according to  claim 10 , wherein continued axial energy forces applied to the energizing ring after reaching the set point is directed through the stop shoulder to the seal ring. 
     
     
         15 . The assembly according to  claim 10 , wherein the stop shoulder is located between the nose and an upper end of the energizing ring. 
     
     
         16 . The assembly according to  claim 10 , wherein the nose end is spaced above a base of the slot while the stop shoulder is contacting the upper end of said one of the inner and outer seal legs. 
     
     
         17 . A method for sealing an annular space in a wellhead assembly between inner and outer wellhead members, comprising:
 providing wickers on at least one of the inner and outer wellhead members;   providing a seal member having inner and outer annular walls defining a slot therebetween, and an annular energizing ring and having an annular stop shoulder,   inserting the seal member between the inner and outer members;   inserting energizing ring into the slot by a downward force on the energizing ring, causing the inner and outer legs to move radially into sealing engagement with the inner and outer wellhead members and into engagement with the wickers;   continuing to apply the downward force after the stop shoulder contacts an upper end of one of the legs, and directing the downward force through said one of the legs to the wickers.   
     
     
         18 . The method according to  claim 17 , wherein the inner leg is contacted by the stop shoulder and wickers are on the inner wellhead member