Soft seat retention

Abstract

A device, such as a valve, having a soft seat disposed in a groove formed in and circumferentially along a hard seating surface of a hard seat and one or more retaining elements disposed in the groove in contact with the soft seat and the hard seat.

What is claimed is: 
     
         1 . A device, comprising:
 a hard seat comprising a hard sealing surface extending circumferentially about an axial bore and having an inner circumferential edge and an outer circumferential edge; and   a soft seat disposed circumferentially along the hard sealing surface between the inner and the outer circumferential edges.   
     
     
         2 . The device of  claim 1 , wherein the hard sealing surface is curved. 
     
     
         3 . The device of  claim 1 , wherein the soft seat is a circular member formed of a pliable material. 
     
     
         4 . The device of  claim 1 , wherein the soft seat is positioned in a groove formed in the hard sealing surface. 
     
     
         5 . The device of  claim 1 , further comprising:
 a groove formed in and circumferentially along the hard sealing surface between the inner and outer edges, the soft seat positioned in the groove and having a soft sealing surface positioned above the hard sealing surface; and   a retainer element disposed in the groove and in contact with the soft seat and the hard seat.   
     
     
         6 . The device of  claim 5 , wherein the retainer element is disposed between the soft seat and the outer circumferential edge. 
     
     
         7 . The device of  claim 5 , wherein the retainer element is an elongated member. 
     
     
         8 . The device of  claim 5 , wherein the retainer element is an elongated member extending circumferentially or substantially circumferentially along the length of the soft seat. 
     
     
         9 . The device of  claim 5 , wherein the retainer element comprises two or more elements spaced circumferentially apart. 
     
     
         10 . The device of  claim 1 , further comprising:
 a groove formed in and circumferentially along the hard sealing surface between the inner and outer edges, the soft seat positioned in the groove and having a soft sealing surface positioned above the hard sealing surface;   an undercut groove formed below the hard sealing surface along circumferentially along the groove; and   a retainer element disposed in the groove and in contact with the soft seat and the hard seat.   
     
     
         11 . The device of  claim 10 , wherein the hard sealing surface is curved. 
     
     
         12 . The device of  claim 10 , wherein the retainer element is an elongated member. 
     
     
         13 . The device of  claim 10 , wherein the retainer element comprises two or more elements spaced circumferentially apart. 
     
     
         14 . The device of  claim 1 , further comprising a flapper having a flapper sealing surface cooperative with the soft seat to provide a seal when the flapper is in a closed position. 
     
     
         15 . A well system, comprising:
 a valve disposed with a tubular string and deployed downhole in a wellbore, the valve comprising:
 a hard seat comprising a hard sealing surface extending circumferentially about an axial bore and having an inner circumferential edge and an outer circumferential edge; 
 a soft seat disposed circumferentially along the hard sealing surface between the inner and the outer circumferential edges; and 
 a flapper having a flapper sealing surface cooperative with the soft seat to provide a seal when the flapper is in a closed position. 
   
     
     
         16 . The system of  claim 1 , wherein the flapper is a curved flapper and the hard sealing surface is curved. 
     
     
         17 . The system of  claim 15 , further comprising:
 a groove formed in and circumferentially along the hard sealing surface between the inner and outer edges, the soft seat positioned in the groove and having a soft sealing surface positioned above the hard sealing surface; and   a retainer element disposed in the groove and in contact with the soft seat and the hard seat.   
     
     
         18 . A method, comprising:
 disposing a valve in a tubular string in a wellbore, the valve comprising:
 a hard seat comprising a hard sealing surface extending circumferentially about an axial bore and having an inner circumferential edge and an outer circumferential edge; 
 a soft seat disposed circumferentially about the hard sealing surface between the inner and the outer circumferential edges; and 
 a flapper having a flapper sealing surface cooperative with the soft seat to provide a seal when the flapper is in a closed position. 
   
     
     
         19 . The method of  claim 18 , wherein the flapper is a curved flapper and the hard sealing surface is curved. 
     
     
         20 . The method system of  claim 18 , wherein the valve further comprises:
 a groove formed in and circumferentially along the hard sealing surface between the inner and outer edges, the soft seat positioned in the groove and having a soft sealing surface positioned above the hard sealing surface; and   a retainer element disposed in the groove and in contact with the soft seat and the hard seat.