Frangible glass barrier valves

Abstract

A downhole temporary barrier valve configured to withstand high fluid pressures and yet be frangible may be achieved by a variety of configurations, processes, and techniques. In particular implementations, a barrier valve may include a housing and a frangible barrier. The housing may include an outer wall and an inner wall, with the inner wall defining a passage through the housing. The frangible barrier may, for example, include a cylindrical base and a curved surface, with the cylindrical base having a bore therethrough and the inner face of the curved surface closing off the bore at one end of the cylindrical base. The curved surface may have a convex outer face and a concave inner face. The frangible disk may be comprised of tempered glass, which may have surface layers and an inner layer, the surface layer being in compression and the inner layer being in tension.

1 . A barrier valve for use downhole in a wellbore, the barrier valve comprising:
 a housing having an outer wall and an inner wall, the inner wall defining a passage through the housing; and   a frangible disk comprising a cylindrical base and a curved surface, the cylindrical base having a bore therethrough and the curved surface having a convex outer face and a concave inner face, the inner face of the curved surface closing off the bore at one end of the cylindrical base;   wherein the frangible disk is comprised of tempered glass.   
     
     
         2 . The barrier valve of  claim 1 , further comprising a seal disposed about the annular base such that it is located between the inner wall of the housing and the outer wall of the annular base. 
     
     
         3 . The barrier valve of  claim 1 , wherein the inner shoulder configured to receive the cylindrical base. 
     
     
         4 . The barrier valve of  claim 1 , further comprising a cartridge for mounting the frangible disk in the housing. 
     
     
         5 . The barrier valve of  claim 4 , wherein the cartridge is mounted around the frangible disk. 
     
     
         6 . The barrier valve of  claim 1 , further comprising a plurality of buttons extending into the passage, wherein the frangible disk can move relative to the housing the inner wall and thereby engage the buttons to destroy the disk. 
     
     
         7 . The barrier valve of  claim 1 , further comprising a piston assembly and a plurality of fingers that are actuatable thereby to impinge upon the side of the frangible disk. 
     
     
         8 . The barrier valve of  claim 1 , further comprising a seal disposed about the curved surface between the curved surface and the inner wall of the housing. 
     
     
         9 . The barrier valve of  claim 8 , wherein the seal is a crush seal. 
     
     
         10 . The barrier valve of  claim 1 , wherein the frangible disk is configured to fracture into pieces having a major diameter of less than 0.25 inches. 
     
     
         11 . A barrier valve for use downhole in a wellbore, the barrier valve comprising:
 a housing having an outer wall and an inner wall, the inner wall defining a passage through the housing;   a frangible barrier comprising a convex upper curved surface and a convex lower surface; and   a mounting member configured to secure the frangible barrier in the housing;   wherein the frangible barrier is comprised of tempered glass.   
     
     
         12 . The barrier valve of  claim 11 , wherein the frangible barrier includes a mid-section having an outer wall, the outer wall mid-section being circular in shape. 
     
     
         13 . The barrier valve of  claim 12 , further comprising a seal disposed about the mid-section such that it is located between the inner wall of the housing and the mid-section. 
     
     
         14 . The barrier valve of  claim 11 , wherein the inner wall of the housing comprises an inner shoulder configured to receive the upper curved surface. 
     
     
         15 . The barrier valve of  claim 11 , further comprising a plurality of buttons that protrude into the passage, frangible barrier being moveable relative to the housing to engage the buttons and destroy the frangible barrier. 
     
     
         16 . The barrier valve of  claim 11 , wherein the mounting member is adapted to move along the inner wall of the housing. 
     
     
         17 . The barrier valve of  claim 16 , wherein the mounting member is configured such that a space exists between the mounting member and the inner wall of the housing, further comprising a rupturable seal assembly in the wall of the housing, wherein rupturing of the seal assembly allows well fluid to enter into the space and move mounting member along the inner wall of the housing. 
     
     
         18 . The barrier valve of  claim 11 , further comprising a piston assembly that actuates a plurality of fingers to impinge upon the side of the frangible barrier thereby destroying it. 
     
     
         19 . The barrier valve of  claim 11 , wherein the frangible barrier is configured to fracture into pieces having a major diameter of less than 0.25 inches.