Shifting tool and associated methods for operating downhole valves

Abstract

A shifting tool can include a flow restrictor outwardly extendable in a well. A method can include flowing a fluid through a flow restriction, thereby creating a pressure differential and, in response, shifting a closure member while the fluid flows through the flow restriction. Another method can include positioning a shifting tool in a tubular string, then outwardly extending keys from the shifting tool in response to fluid pressure applied to the shifting tool, then engaging the keys with a profile formed in a closure member, and then shifting the closure member between open and closed positions.

1 . A shifting tool for use in a subterranean well, the shifting tool comprising:
 a flow restrictor outwardly extendable in the well from a radially retracted position to a radially extended position,   in which the flow restrictor comprises at least one ring.   
     
     
         2 . The shifting tool of  claim 1 , in which the at least one ring is resilient and is radially outwardly extendable in response to longitudinal displacement of a sleeve relative to the resilient ring. 
     
     
         3 . The shifting tool of  claim 1 , in which the flow restrictor is outwardly extendable in response to compression of the shifting tool. 
     
     
         4 . The shifting tool of  claim 1 , in which the flow restrictor is outwardly extendable in response to a longitudinal force applied to the shifting tool. 
     
     
         5 . The shifting tool of  claim 1 , in which the flow restrictor is inwardly retractable in response to a longitudinal force applied to the shifting tool. 
     
     
         6 . The shifting tool of  claim 1 , further comprising:
 at least one outwardly extendable key configured to engage a downhole profile;   a retainer that retains the key in an inwardly retracted position; and   a piston displaceable in response to a pressure differential between an exterior and an interior of the shifting tool, the key being permitted to extend outward in response to displacement of the piston.   
     
     
         7 . The shifting tool of  claim 6 , in which the pressure differential comprises a pressure on the interior of the shifting tool being greater than a pressure on the exterior of the shifting tool. 
     
     
         8 . The shifting tool of  claim 6 , further comprising a valve that selectively prevents and permits fluid communication between the exterior and the interior of the shifting tool. 
     
     
         9 . The shifting tool of  claim 8 , in which the retainer, the piston and a closure member of the valve are formed on a sleeve that is longitudinally displaceable relative to a generally tubular inner mandrel of the shifting tool. 
     
     
         10 . The shifting tool of  claim 8 , in which a closure member of the valve is displaceable with the piston. 
     
     
         11 . The shifting tool of  claim 8 , further comprising a ratchet device that permits displacement of a closure member of the valve to an open position, but prevents displacement of the closure member from the open position to a closed position. 
     
     
         12 - 23 . (canceled) 
     
     
         24 . A method of operating at least one downhole valve connected in a tubular string in a subterranean well, the method comprising:
 positioning a shifting tool in the tubular string;   then outwardly extending keys from the shifting tool, in response to fluid pressure applied to the shifting tool;   then engaging the keys with a profile formed in a closure member of the downhole valve; and   then shifting the closure member between open and closed positions.   
     
     
         25 . The method of  claim 24 , in which the fluid pressure is applied to an annulus formed between the shifting tool and the downhole valve. 
     
     
         26 . The method of  claim 24 , further comprising displacing a flow restrictor radially outward from the shifting tool. 
     
     
         27 . The method of  claim 26 , in which the flow restrictor displaces radially outward in response to axial compression of the shifting tool downhole. 
     
     
         28 . The method of  claim 26 , in which the flow restrictor displacing comprises reducing an annular flow area between the shifting tool and the downhole valve. 
     
     
         29 . The method of  claim 26 , in which the flow restrictor displaces radially outward after the keys are engaged with the closure member. 
     
     
         30 . The method of  claim 26 , further comprising displacing the flow restrictor radially inward after the flow restrictor is displaced radially outward. 
     
     
         31 . The method of  claim 24 , in which the closure member shifting comprises flowing a fluid through a flow restriction, thereby creating a pressure differential across the flow restriction. 
     
     
         32 . The method of  claim 31 , in which the closure member shifts in response to the pressure differential, while the fluid flows through the flow restriction. 
     
     
         33 . The method of  claim 31 , further comprising forming the flow restriction radially between the shifting tool and the downhole valve. 
     
     
         34 . The method of  claim 31 , further comprising forming the flow restriction radially between the shifting tool and the closure member. 
     
     
         35 . The method of  claim 31 , in which the shifting tool is engaged with the closure member profile while the fluid flows through the flow restriction. 
     
     
         36 . The method of  claim 24 , in which the closure member shifting comprises shifting the closure member to the open position, and in which the method further comprises then shifting the closure member to the closed position. 
     
     
         37 . A shifting tool for use in a subterranean well, the shifting tool comprising:
 at least one outwardly extendable key configured to engage a downhole profile;   a retainer that retains the key in an inwardly retracted position; and   a piston displaceable in response to a pressure differential between an exterior and an interior of the shifting tool, the key being permitted to extend outward in response to displacement of the piston.   
     
     
         38 . The shifting tool of  claim 37 , in which the pressure differential comprises a pressure on the interior of the shifting tool being greater than a pressure on the exterior of the shifting tool. 
     
     
         39 . The shifting tool of  claim 37 , further comprising a valve that selectively prevents and permits fluid communication between the exterior and the interior of the shifting tool. 
     
     
         40 . The shifting tool of  claim 39 , in which the retainer, the piston and a closure member of the valve are formed on a sleeve that is longitudinally displaceable relative to a generally tubular inner mandrel of the shifting tool. 
     
     
         41 . The shifting tool of  claim 39 , in which a closure member of the valve is displaceable with the piston. 
     
     
         42 . The shifting tool of  claim 39 , further comprising a ratchet device that permits displacement of a closure member of the valve to an open position, but prevents displacement of the closure member from the open position to a closed position. 
     
     
         43 . The shifting tool of  claim 37 , further comprising an outwardly extendable flow restrictor. 
     
     
         44 . The shifting tool of  claim 43 , in which the flow restrictor is outwardly extendable in response to compression of the shifting tool. 
     
     
         45 . The shifting tool of  claim 43 , in which the flow restrictor is outwardly extendable in response to a longitudinal force applied to the shifting tool. 
     
     
         46 . The shifting tool of  claim 43 , in which the flow restrictor is inwardly retractable in response to a longitudinal force applied to the shifting tool.