Interventionless Second Closure Operable with a Tubular String Isolation Valve

Abstract

A barrier is provided in a tubular string for opening up the top of the well for drilling or completion applications. In applications where two barriers are required due to regulations a control line actuated safety valve could serve as a first barrier which a flapper is held open by a first sleeve with a seat. Another barrier (disclosed here) actuated by a first object landing on a seat to force the sleeve away from the flapper to allow the flapper to close to serve as a second barrier. After the top of the well is reclosed after being open a second object engages a seat on a second sleeve to push the flapper back to open and to lock the flapper in the open position. The objects degrade or are blown through the seats leaving the tubular passage open for the passage of tools or production flow.

We claim: 
     
         1 . A barrier assembly for a borehole tubular string, comprising:
 an isolation valve selectively obstructing the passage within the tubular string, said isolation valve selectively movable with at least one first object landed on a first actuation assembly for said isolation valve in said passage for operation of said actuation assembly to close said passage, said passage subsequently reopened with at least one second object on a second actuation assembly.   
     
     
         2 . The assembly of  claim 1 , wherein:
 said at least one first object temporarily blocks said passage when engaged to said first actuation assembly.   
     
     
         3 . The assembly of  claim 1 , wherein:
 said isolation valve comprises a flapper.   
     
     
         4 . The assembly of  claim 1 , wherein:
 said at least one first object moves in tandem with said first actuation assembly under applied pressure in said passage with said at least one first object in contact with said first actuation assembly.   
     
     
         5 . The assembly of  claim 1 , wherein:
 said at least one first object degrades or is forced with passage pressure to pass through said first actuation assembly.   
     
     
         6 . The assembly of  claim 1 , wherein:
 said second actuation assembly selectively engaged to a valve member of said isolation valve for retaining said valve member in a passage open position.   
     
     
         7 . The assembly of  claim 6 , wherein:
 said first actuating assembly comprises a first sleeve comprising a first seat in a first opening therethrough, said at least one first object landing on said first seat for tandem movement therewith under pressure applied in said passage.   
     
     
         8 . The assembly of  claim 7 , wherein:
 movement of said first sleeve releases a flapper to move to a flapper seat to act as a closure to said isolation valve.   
     
     
         9 . The assembly of  claim 8 , wherein:
 said first sleeve is locked after said tandem movement with said at least one object.   
     
     
         10 . The assembly of  claim 8 , wherein:
 said at least one first object moving through said first opening in said first sleeve after movement of said first sleeve by degrading or by pressure forcing.   
     
     
         11 . The assembly of  claim 8 , wherein:
 said first sleeve degrades or is forced with said at least one first object with pressure along said tubular string away from said flapper to close said passage.   
     
     
         12 . The assembly of  claim 8 , wherein:
 said second actuating assembly comprises a second sleeve having a second seat in a second opening, said second sleeve disposed on the opposite side of said flapper from said first sleeve.   
     
     
         13 . The assembly of  claim 12 , wherein:
 said second sleeve selectively pushes said flapper away from said flapper seat.   
     
     
         14 . The assembly of  claim 13 , wherein:
 said second sleeve locks in said passage after pushing said flapper away from said flapper seat.   
     
     
         15 . The assembly of  claim 12 , wherein:
 said at least one second object allowing pressure to move said at least one second object and said second sleeve in tandem to push said flapper away from said flapper seat.   
     
     
         16 . The assembly of  claim 15 , wherein:
 said at least one second object passes through said second opening by applied pressure in said passage or by degradation.   
     
     
         17 . The assembly of  claim 15 , wherein:
 said at least one second object is larger than said at least one first object landed on said first sleeve.   
     
     
         18 . The assembly of  claim 15 , wherein:
 said second sleeve locks in said passage after pushing said flapper away from said flapper seat with collets moving into a recess, whereupon a bore in said second sleeve defines a drift dimension of said passage.   
     
     
         19 . The assembly of  claim 7 , wherein:
 said first sleeve holds said flapper open for running the tubular string into the borehole.   
     
     
         20 . The assembly of  claim 15 , wherein:
 said second sleeve is removably mounted to increase a drift dimension of said passage.