Full bore injection valve

Abstract

The present invention generally relates to controlling the flow of fluids in a wellbore. In one aspect, a valve for selectively closing a flow path through a wellbore in a first direction is provided. The valve includes a body and a piston surface formable across the flow path in the first direction. The piston surface is formed at an end of a shiftable member annularly disposed in the body. The valve further includes a flapper member, the flapper member closable to seal the flow path when the shiftable member moves from a first position to a second position due to fluid flow acting on the piston surface. In another aspect, a valve for selectively closing a flow path through a wellbore in a single direction is provided. In yet another aspect, a method for selectively closing a flow path through a wellbore in a first direction is provided.

1 . A valve for selectively closing a flow path through a wellbore in a first direction, the valve comprising: 
 a body;    a piston surface formable across the flow path in the first direction, the piston surface formed at an end of a shiftable member annularly disposed in the body; and    a flapper member, the flapper member closable to seal the flow path when the shiftable member moves from a first position to a second position due to fluid flow acting on the piston surface.    
   
   
       2 . The valve of  claim 1 , wherein the piston surface includes a plurality of members.  
   
   
       3 . The valve of  claim 2 , wherein each member is annularly disposed within the shiftable member.  
   
   
       4 . The valve of  claim 2 , wherein each member is biased inward toward a centerline of the body.  
   
   
       5 . The valve of  claim 1 , wherein the piston surface is formable across the flow path upon fluid flow in a second direction.  
   
   
       6 . The valve of  claim 1 , wherein the flapper member is movable between an open position and a closed position.  
   
   
       7 . The valve of  claim 6 , wherein the flow tube retains the flapper member in the open position when the flow tube is in the first position.  
   
   
       8 . The valve of  claim 1 , wherein the piston surface is coated with an abrasion resistant material.  
   
   
       9 . The valve of  claim 1 , wherein the shiftable member is biased in the first position by a biasing member.  
   
   
       10 . A valve for selectively closing a flow path through a wellbore in a single direction, the valve comprising: 
 a housing;    a variable piston surface area formable across the flow path in the single direction;    a flow tube axially movable within the housing between a first and a second position due to fluid flow acting on the variable piston surface; and    a flapper for closing the flow path through the valve upon movement of the flow tube to the second position.    
   
   
       11 . The valve of  claim 10 , wherein the variable piston surface includes a plurality of members.  
   
   
       12 . The valve of  claim 11 , wherein each member is movable between a smaller surface area position and a larger surface area position.  
   
   
       13 . The valve of  claim 12 , wherein each member is biased in the larger surface area position.  
   
   
       14 . The valve of  claim 10 , wherein the variable piston surface area is formable across the flow path upon fluid flow in a direction opposite the single direction.  
   
   
       15 . A method for selectively closing a flow path through a wellbore in a first direction, the method comprising: 
 positioning a valve in the wellbore, the valve having a body, a formable piston surface at an end of a shiftable member, and a flapper member;    reducing the flow in the first direction, thereby forming the piston surface;    commencing a flow in a second direction against the piston surface to move the shiftable member away from a position adjacent the flapper member; and    closing the flapper member to seal the flow path through the wellbore.    
   
   
       16 . The method of  claim 15 , wherein the piston surface includes a plurality of members.  
   
   
       17 . The method of  claim 16 , further including moving the plurality of members from an open position to a closed position to form the piston surface.  
   
   
       18 . The method of  claim 17 , further including biasing the plurality of members in the closed position.  
   
   
       19 . The method of  claim 15 , further including reducing the flow in the second direction to move the shiftable member adjacent the flapper, thereby opening the flow path in the first direction.  
   
   
       20 . The method of  claim 19 , further including locking the valve in an open position to maintain the flow path through the wellbore.