Packoff Sealing Assembly

Abstract

A packoff assembly for sealing a space between an inner well member and an outer well member. The packoff assembly has a packoff body, and a sealing mechanism with a U-shaped cross-section, including a packoff body leg and a well component leg extending substantially downward from a transverse connecting section. The well component leg is elastically bendable so that it resists inward deflection toward the packoff body and so that the sealing mechanism can be set without the use of an energizing ring. The packoff body leg is configured for engagement with the packoff body, and the well component leg has a sealing surface configured for sealing engagement with the inner or the outer well member.

What is claimed is: 
     
         1 . A packoff assembly for sealing a space between an inner well member and an outer well member, the packoff assembly comprising:
 a packoff body configured for insertion between the inner well member and the outer well member; and   a sealing mechanism for scaling between the packoff body and the inner or outer well member, the sealing mechanism having a U-shaped cross-section including a packoff body leg and a well component leg extending substantially downward from a transverse connecting section, the well component leg having a sealing surface configured for sealing engagement with the inner or outer well member,   the well component leg being elastically bendable so that it resists inward deflection toward the packoff body and so that the sealing mechanism can be set without the use of an energizing ring.   
     
     
         2 . The packoff body of  claim 1 , wherein the sealing mechanism further comprises an inlay positioned on the sealing surface of the well component leg, and configured to sealingly engage the inner or outer well member. 
     
     
         3 . The packoff assembly of  claim 1 , wherein the packoff body leg is separate from, and configured for positioning adjacent to, the packoff body. 
     
     
         4 . The packoff assembly of  claim 1 , wherein the packoff body leg is integral with the packoff body. 
     
     
         5 . The packoff assembly of  claim 1 , wherein the inner well member is a casing hanger. 
     
     
         6 . The packoff assembly of  claim 1 , wherein the outer well member is a wellhead. 
     
     
         7 . The packoff assembly of  claim 1 , wherein the sealing mechanism is composed of metal. 
     
     
         8 . The packoff assembly of  claim 2 , wherein the inlay is made of a metal that is softer than the metal of the well members so that as the well component leg seals against the well member, the inlay deforms to conform to the surface of the well member. 
     
     
         9 . The packoff assembly of  claim 1 , wherein the well component leg is positioned so that the sealing surfaces are conically shaped when the packoff assembly is not installed between the inner and outer well members. 
     
     
         10 . The packoff assembly of  claim 1 , wherein the well component leg is positioned to that the sealing surfaces are cylindrically shaped when the packoff assembly is installed between the inner and outer well members and the sealing surfaces are engaged with the inner or outer well member. 
     
     
         11 . The packoff body of  claim 2 , wherein the inlay is soldered onto the surface of the well component leg of the sealing mechanism. 
     
     
         12 . A seal assembly for sealing a space between an inner well member and an outer well member, the seal assembly comprising:
 a packoff body;   a pair of seals configured for positioning between the packoff body and the inner and outer well members, the seals having U-shaped cross-sections, each with a packoff body leg and a well component leg extending downwardly from a transverse connecting section, the well component legs of the seals being elastically bendable so as to resist inward deflection toward the packoff body, and to enable the seals to be set without the use of an energizing ring;   the packoff body legs configured to threadedly engage the packoff body; and   the well component legs having a sealing surface configured to mate with, and seal against, the sealing surface of the inner or outer well component.   
     
     
         13 . The seal assembly of  claim 12 , wherein each seal further comprises an inlay that is softer than the well members and that is attached to the well component legs, so that as the sealing surface of each well component leg seals against the sealing surface of the well component, the inlay deforms to conform to the surface of the well component, thereby strengthening the seal between the well component leg and the well component. 
     
     
         14 . The seal assembly of  claim 12 , further comprising:
 wiper rings installed on the packoff body below the pair of seals to clear debris from the well members as the packoff body and seals are positioned relative to the well members.   
     
     
         15 . The seal assembly of  claim 12 , further comprising:
 upper seals positioned above the pair of seals to form an additional upper seal between the packoff body and the well members, and to isolate the pair of seals from pressure above the upper seals.   
     
     
         16 . The seal assembly of  claim 12 , wherein the inner well member is a casing hanger. 
     
     
         17 . The seal assembly of  claim 12 , wherein the outer well member is a wellhead. 
     
     
         18 . The seal assembly of  claim 12 , wherein the pair of seals are composed of metal. 
     
     
         19 . The seal assembly of  claim 13 , wherein the inlay is composed of annealed silver. 
     
     
         20 . A seal assembly for sealing the space between a wellhead and a casing hanger, the sealing assembly comprising:
 a packoff body configured for insertion between the wellhead and the casing hanger;   a pair of annular metal seals for sealing between the packoff body and the wellhead and casing hanger, the pair of annular metal seals each having a U-shaped cross-section including a packoff body leg and a well component leg extending substantially downward from a transverse connecting section, the well component leg having a sealing surface configured for sealing engagement with the wellhead or the casing hanger, the well component leg being elastically bendable so that it resists inward deflection toward the packoff body and so that the pair of annular metal seals can be set without the use of an energizing ring;   a pair of wiper rings attached to the packoff body below the pair of annular metal seals and configured to contact and wipe clean the surfaces of the wellhead and the casing hanger as the seal assembly is inserted therebetween;   a retainer plate attached to the bottom of the packoff body and extending radially outward therefrom to retain the position of the pair of annular metal seals and the pair of wiper rings relative to the packoff body; and   a pair of upper elastomeric seals positioned above the annular metal seals and configured to seal between the packoff body and the wellhead and casing hanger and to isolate the pair of seals from pressure above the upper seals.