Systems and techniques to actuate isolation valves

Abstract

A tool that is usable in a well and may include an operator, a switch, a resilient device and an indexer. The switch may be configured to selectively communicate a first force to the operator, thereby actuating the tool. The resilient device may exert a second force. The indexer may cycle through a sequence of positions in response to alternating between the second force and a third force. The sequence includes a predetermined position configured to actuate the switch, thereby communicating the first force to the operator to actuate the tool.

1 . A tool usable in a well, comprising:
 an operator having a head disposed within a cavity of a housing of the tool, the cavity being selectively supplied with hydraulic fluid through a passageway;   a switch positioned in the passageway to selectively communicate a first force to the operator to actuate the tool by opening the passageway to flow of the hydraulic fluid;   a compensator coupled to the passageway to supply the hydraulic fluid under pressure via a compensator piston exposed to well pressure in a surrounding annulus; and   an indexer operated by a piston head exposed to a force generated by well pressure on one side and to an opposed force generated by a resilient member on the other side, the indexer being able to cycle through a sequence of positions in response to the force and the opposed force, the sequence including a position to cause the switch to open the passageway to flow of the hydraulic fluid to shift the operator.   
     
     
         2 . The tool of  claim 1 , wherein the first force comprises a force produced by fluid in the surrounding annulus disposed within a casing in the well. 
     
     
         3 . The tool of  claim 1 , wherein the first force comprises a force produced by fluid in an annulus of the well. 
     
     
         4 . The tool of  claim 1 , wherein
 the tool comprises a valve, and   the operator comprises a mandrel to operate a valve element of the valve.   
     
     
         5 . The tool of  claim 4 , wherein the valve is a formation isolation valve. 
     
     
         6 . The tool of  claim 1 , wherein the resilient member comprises a mechanical spring. 
     
     
         7 . The tool of  claim 4 , wherein a central passageway of the valve further comprises a seat configured to interact with a flowable object so as to facilitate the production of the first force in the central passageway. 
     
     
         8 . The tool of  claim 1 , further comprising an index locator configured to correlate to a position of the indexer in the sequence of positions. 
     
     
         9 . The tool of  claim 8 , wherein the index locator comprises a magnetic field. 
     
     
         10 . A method usable with a well, comprising:
 coupling an operator with a compensator via a passageway containing hydraulic fluid, the compensator being acted on by well pressure in a wellbore;   controlling flow of the hydraulic fluid through the passageway with a switch;   connecting the switch to an indexer;   selectively opening the switch by transitioning the indexer through a sequence of positions in response to sequential opposing forces exerted by a resilient member and at least one other force from a source other than the resilient member, the selectively opening causing movement of the operator via flow of the hydraulic fluid through the passageway; and   actuating a formation isolation valve through movement of the operator.   
     
     
         11 . The method of  claim 10 , further comprising:
 deploying a flowable object into the well; and
 generating the operating force due to an interaction between the flowable object and the formation isolation valve. 
   
     
     
         12 . The method of  claim 10 , further comprising:
 deploying a flowable object into the well;   seating the flowable object in a central passageway of the formation isolation valve; and   generating the operating force due to the seating of the flowable object and the formation isolation valve.   
     
     
         13 . A method of determining a position of an indexer in a sequence of positions, the method comprising:
 providing an index locator coupled to the indexer;   detecting a location of the index locator; and   indicating the location of the index locator to a point external from a housing of the indexer.   
     
     
         14 . The method of  claim 13 , in which the index locator generates a magnetic field. 
     
     
         15 . A method usable with a well, comprising:
 deploying a flowable object in the well;   interacting the flowable object with a formation isolation valve disposed in the well; and   generating a force to actuate the formation isolation valve due to the interaction between the flowable object and the formation isolation valve.   
     
     
         16 . The method of  claim 15 , wherein the interacting comprises abutting the flowable object against a seat in a central passageway of the formation isolation valve; and
 wherein the generating of the force comprises building fluid pressure above the formation isolation valve