Valve Apparatus Having Dissolvable or Frangible Flapper and Method of Using Same

Abstract

A bridge plug for use in a wellbore having an anchoring system to grip the inner surface of the surrounding wellbore, as well as a sealing system or packing element to seal against the inner surface. A hinged flapper permits flow of fluid in one axial direction through a central through bore, but can selectively contact against a seat to create a fluid pressure seal and prevent fluid flow through said central through bore in an opposite axial direction. The flapper can be manufactured of frangible material and/or dissolvable material, permitting selective removal of the flapper when desired.

What is claimed: 
     
         1 . A valve assembly comprising:
 a) a body section having an upper surface, outer surface, and a central flow bore defining a first diameter, and having an upper opening defining a seat at said upper surface;   b) at least one slip member disposed on said outer surface adapted to selectively grip against an inner surface of a wellbore;   c) at least one elastomeric sealing member disposed on said outer surface adapted to selectively form a fluid pressure seal against said inner surface of said wellbore;   d) a flapper hingedly attached to said body section, wherein said flapper can move between a substantially open configuration, and a substantially closed configuration wherein said flapper contacts said seat and said transverse support member; and   e) a spring configured to bias said flapper off of said seat until fluid pressure acting on said flapper overcomes force exerted by said spring.   
     
     
         2 . The valve assembly of  claim 1 , wherein said valve assembly can be conveyed into said wellbore on wireline and set using a wireline setting tool. 
     
     
         3 . The valve assembly of  claim 1 , wherein said valve assembly can be conveyed into said wellbore on pipe and set using a hydraulic setting tool. 
     
     
         4 . The valve assembly of  claim 1 , wherein said flapper is constructed of frangible material adapted to selectively break into smaller pieces in response to application of a predetermined force to said flapper. 
     
     
         5 . The valve assembly of  claim 4 , wherein said smaller pieces can be circulated out of said wellbore when broken. 
     
     
         6 . The valve assembly of  claim 1 , wherein said flapper is constructed of dissolvable material. 
     
     
         7 . The valve assembly of  claim 6 , wherein said dissolvable flapper is adapted to substantially uncover said central flow bore after dissolving. 
     
     
         8 . A method of performing hydraulic fracturing operations in a wellbore comprising:
 a) conveying a valve assembly into a wellbore, wherein said valve assembly comprises:
 i) a body section having an upper surface, an outer surface and a central flow bore defining a first diameter, and having an upper opening defining a seat at said upper surface; 
 ii) at least one slip member disposed on said outer surface adapted to selectively grip against an inner surface of said wellbore; 
 iii) at least one elastomeric sealing member disposed on said outer surface adapted to selectively form a fluid pressure seal against the inner surface of said wellbore; 
 iv) a flapper hingedly attached to said body section, wherein said flapper can move between a substantially open configuration, and a substantially closed configuration wherein said flapper contacts said seat and said transverse support member; 
 v) a spring configured to bias said flapper off of said seat; 
   b) setting said valve assembly at a desired position in said wellbore;   c) applying fluid pressure to said flapper;   d) closing said flapper when fluid pressure applied to said flapper overcomes force exerted by said spring; and   e) conducting hydraulic fracturing operations in said wellbore.   
     
     
         9 . The method of  claim 8 , wherein said valve assembly is conveyed into said wellbore on wireline and set using a wireline setting tool. 
     
     
         10 . The method of  claim 8 , wherein said valve assembly is conveyed into said wellbore on pipe and set using a hydraulic setting tool. 
     
     
         11 . The method of  claim 8 , wherein said flapper is constructed of frangible material adapted to selectively break into smaller pieces in response to application of a predetermined force to said flapper. 
     
     
         12 . The method of  claim 11 , wherein said smaller pieces can be circulated out of said wellbore when broken. 
     
     
         13 . The method of  claim 8 , wherein said flapper is constructed of dissolvable material. 
     
     
         14 . The method of  claim 13 , wherein said dissolvable flapper is dissolved to substantially uncover said central flow bore following completion of said hydraulic fracturing operations. 
     
     
         15 . A valve assembly comprising:
 a) a body section having an upper surface, a lower surface, an outer surface, a central flow bore defining a first diameter, and having an upper opening defining a seat at said upper surface, a hinge post disposed at said upper surface, and notch disposed at said lower surface;   b) a support ring disposed at said seat and defining a second diameter;   c) at least one ball transfer unit disposed on said outer surface configured to contact an inner surface of a wellbore;   d) at least one slip member disposed on said outer surface configured to selectively grip against said inner surface of said wellbore;   e) at least one elastomeric sealing member disposed on said outer surface adapted to selectively form a fluid pressure seal against said inner surface of said wellbore; and   f) a flapper hingedly attached to said hinge post of said body section, wherein said flapper can move between a substantially open configuration, and a substantially closed configuration wherein said flapper contacts said seat and said transverse support member.   
     
     
         16 . The valve assembly of  claim 15 , wherein said flapper and said support ring are constructed of frangible material adapted to selectively break into smaller pieces in response to application of a predetermined force to said flapper and said support ring. 
     
     
         17 . The valve assembly of  claim 16 , wherein said smaller pieces can be circulated out of said wellbore when broken. 
     
     
         18 . The valve assembly of  claim 15 , wherein said flapper and said support ring are constructed of dissolvable material. 
     
     
         19 . The valve assembly of  claim 18 , wherein said dissolvable flapper and said dissolvable support ring are adapted to substantially uncover said central flow bore after dissolving. 
     
     
         20 . The valve assembly of  claim 15 , wherein said hinge post is configured to be selectively received within a notch of an adjacent valve assembly disposed in said wellbore.