Wellhead annulus seal having a wickered surface

Abstract

An annular seal for use in a wellhead assembly has inner and outer legs that each extend in a direction that is generally parallel with an axis of the seal to define an annular space therebetween. Wickers are provided on an outer surface of the seal, so that when the seal is energized and the legs are urged radially apart from one another, the wickers engage with a mating surface of a downhole tubular. Embedding the wickers into the tubular creates a flow barrier across the interface between the seal and the tubular. The wickers deform the surface of the tubular, which creates a lock down force that opposes relative axial movement of the tubular.

What is claimed is: 
     
         1 . A seal assembly for use in a wellhead assembly comprising:
 an annular seal body comprising,
 an elongate inner leg, 
 an elongate outer leg set radially outward from the inner leg, and 
 an elongate slot defined between the inner and outer legs; and 
   wickers on a curved surface of the seal body that are selectively engaged with a tubular within the wellhead assembly.   
     
     
         2 . The seal assembly of  claim 1 , wherein the wickers are on the inner leg. 
     
     
         3 . The seal assembly of  claim 1 , wherein the wickers are on the outer leg. 
     
     
         4 . The seal assembly of  claim 1 , wherein the wickers are on the inner and the outer leg. 
     
     
         5 . The seal assembly of  claim 1 , wherein the tubular comprises a casing hanger. 
     
     
         6 . The seal assembly of  claim 1 , wherein the tubular comprises a tubing hanger. 
     
     
         7 . The seal assembly of  claim 1 , wherein the tubular comprises a wellhead housing. 
     
     
         8 . The seal assembly of  claim 1 , further comprising a protective foam layer adhered to the wickers. 
     
     
         9 . A wellhead assembly comprising:
 inner and outer wellhead tubulars;   an annulus between the inner and outer tubulars;   an annular seal in the annulus comprising,
 an inner leg that is in selective sealing contact with the inner tubular, 
 an outer leg that is in selective sealing contact with the outer tubular, 
 a space between the inner and outer legs, and 
 wickers on a circumference of a curved surface of the seal. 
   
     
     
         10 . The wellhead assembly of  claim 9 , wherein the wickers are on an inner surface of the inner leg and project into an outer surface of the inner tubular. 
     
     
         11 . The wellhead assembly of  claim 9 , wherein the wickers are on an outer surface of the outer leg and project into an inner surface of the outer tubular. 
     
     
         12 . The wellhead assembly of  claim 9 , wherein wickers are on an inner surface of the inner leg and are on an outer surface of the outer leg. 
     
     
         13 . The wellhead assembly of  claim 9 , further comprising an inlay in one of the inner and outer tubulars that is strategically located for engagement with the wickers when the legs are in sealing contact with the tubulars. 
     
     
         14 . The wellhead assembly of  claim 9 , wherein the seal comprises nickel alloy. 
     
     
         15 . A method of sealing an annulus between an inner and outer tubular in a wellhead assembly comprising:
 (a) providing a seal assembly comprising an annular seal body with inner and outer legs, and with wickers that circumscribe a curved surface on the body;   (b inserting the seal assembly into the annulus;   (c) urging the inner and outer legs radially apart and into respective sealing engagement with an outer surface of the inner tubular and an inner surface of the outer tubular.   
     
     
         16 . The method of  claim 15 , wherein the wickers are on an outer surface of the outer leg and embed into the inner surface of the outer tubular during step (c). 
     
     
         17 . The method of  claim 15 , wherein the wickers are on an inner surface of the inner leg and embed into the outer surface of the inner tubular during step (c). 
     
     
         18 . The method of  claim 15 , further comprising, removing the seal assembly from the wellhead assembly, applying a protective layer onto the wickers, and repeating steps (b) and (c).