Pressure testable hydraulically activated wellbore tool

Abstract

A wellbore tool is provided that can withstand applied pressure tests without becoming hydraulically actuated. The wellbore tool includes a tubular housing including an inner bore; a tool mechanism responsive to fluid pressure; and an indexing mechanism that indexes responsive to tubing pressure cycles of at least an indexing pressure. The indexing mechanism is configured to activate the tool mechanism after a preset number of indexes. The wellbore tool can be pressure tested at pressures above an activation pressure without activating the tool mechanism.

1 . A wellbore tool comprising:
 a tubular housing having an inner surface and an outer surface, the inner surface defining a central bore;   a tool mechanism responsive to hydraulic pressure; and   an indexing mechanism that indexes responsive to tubing pressure cycles of at least an indexing pressure, the indexing mechanism having an adjustable indexing pressure and configured to activate the tool mechanism after a preset number of indexes, wherein the wellbore tool is pressure testable at pressures above an activation pressure without activating the tool mechanism for a number of tubing pressure test cycles.   
     
     
         2 . The wellbore tool of  claim 1 , wherein the indexing pressure is adjustable such that the indexing pressure is defined for the number of tubing pressure test cycles. 
     
     
         3 . The wellbore tool of  claim 1 , wherein the indexing mechanism comprises a biasing member to bias the indexing mechanism against pressure applied to the indexing mechanism and a hydrostatic preloader adjustable to preload the biasing member to adjust the adjustable indexing pressure. 
     
     
         4 . The wellbore tool of  claim 3 , wherein the indexing mechanism comprises:
 a ratchet mechanism defining a plurality of indexing positions and comprising a movable ratchet and an indexing member translatable through the plurality of indexing positions from an initial indexing position to a final indexing position; and   an indexing piston adapted to move the movable ratchet to incrementally advance the indexing member in a first direction; and   wherein the biasing member biases the indexing piston in a second direction.   
     
     
         5 - 28 . (canceled) 
     
     
         29 . A wellbore tool comprising:
 a tubular housing having an inner surface and an outer surface, the inner surface defining a central bore;   a tool mechanism responsive to hydraulic pressure; and   an indexing mechanism that indexes responsive to tubing pressure cycles of at least an indexing pressure, the indexing mechanism configured to activate the tool mechanism after a preset number of indexes, the indexing mechanism comprising an activation mechanism adapted to punch an opening in a device to activate the tool mechanism,   wherein the wellbore tool is pressure testable at pressures above an activation pressure without activating the tool mechanism for a number of tubing pressure test cycles.   
     
     
         30 . The wellbore tool of  claim 29 , wherein the device comprises a rupture disk. 
     
     
         31 . The wellbore tool of  claim 29 , wherein the activation mechanism further comprises:
 an activation member movable from an activation member initial position to an activation member second position and wherein the indexing mechanism comprises an indexing piston adapted to drive the activation member to punch the opening in the device.   
     
     
         32 . The wellbore tool of  claim 31 , wherein the activation mechanism is adapted to open a flow path through the indexing mechanism when activated. 
     
     
         33 . The wellbore tool of  claim 32 , wherein the indexing mechanism is configured to isolate the tool mechanism from the central bore to prevent the tool mechanism from prematurely activating and to activate the tool mechanism after the preset number of indexes by opening the flow path through the indexing mechanism to fluidly connect the central bore to the tool mechanism. 
     
     
         34 - 35 . (canceled) 
     
     
         36 . The wellbore tool of  claim 29 , wherein:
 the indexing mechanism comprises a ratchet mechanism, the ratchet mechanism defining a plurality of indexing positions and comprising a movable ratchet and an indexing member translatable in an indexing mechanism bore through the plurality of indexing positions from an initial indexing position to a final indexing position; and   the indexing piston is adapted to move the movable ratchet to incrementally advance the indexing member in a first direction, through a series of pressure responsive actuations, from the initial indexing position to the final indexing position and to push the indexing member against the activation member to shift the activation member from the activation member initial position to the activation member second position.   
     
     
         37 . The wellbore tool of  claim 36 , wherein:
 the ratchet mechanism further comprises a first indexing profile disposed on an inner wall surface of an indexing mechanism bore;   the movable ratchet comprises a second indexing profile; and   the indexing member is disposed between the inner wall surface and the movable ratchet, the indexing member having an outer surface with a third indexing profile selected to engage the first indexing profile and an inner surface with a fourth indexing profile selected to engage the second indexing profile, wherein the first indexing profile, second indexing profile, third indexing profile and fourth indexing profile are selected such that the indexing member is movable with the movable ratchet in the first direction and is stopped against movement with the movable ratchet in a second direction.   
     
     
         38 . The wellbore tool of  claim 36 , wherein the indexing mechanism comprises
 a biasing member that biases the indexing piston in a second direction;   a stroke limiter to limit an indexing stroke length of the indexing piston; and   a hydrostatic preloader settable to preload the biasing member to adjust the indexing pressure.   
     
     
         39 . The wellbore tool of  claim 29 , wherein the indexing mechanism changes from an indexing configuration to an activation configuration upon reaching the preset number of indexes, wherein in the activation configuration, the indexing mechanism is responsive to the activation pressure to activate the tool mechanism. 
     
     
         40 . The wellbore tool of  claim 39 , wherein the activation pressure is the same as the indexing pressure. 
     
     
         41 . The wellbore tool of  claim 29 , wherein the tubular housing has one or more ports through a housing wall that are openable to connect the central bore to the outer surface and wherein the tool mechanism comprises a sliding sleeve slidable from a port closed position blocking the one or more ports to a port open position at least partially retracted from the one or more ports. 
     
     
         42 . The wellbore tool of  claim 41 , wherein the indexing mechanism is configured to isolate the tool mechanism from the central bore to prevent the tool mechanism from prematurely activating and to activate the tool mechanism to open the sliding sleeve after the preset number of indexes by opening a flow path from the central bore to the tool mechanism. 
     
     
         43 - 79 . (canceled) 
     
     
         80 . A method for actuating a downhole tool, the method comprising:
 installing a wellbore tool in a wellbore, the wellbore tool comprising an indexing mechanism configured to index pressure cycles of at least an indexing pressure and activate the wellbore tool after a preset number of indexes;   conducting one or more pressure tests of the tubing string by applying one or more test pressures to the tubing string such that a tubing pressure at the wellbore tool during the one or more pressure tests is above the indexing pressure for the wellbore tool; and   after completion of the one or more pressure tests, applying pressure to the tubing string to complete remaining index cycles and cause the indexing mechanism to punch an opening in a device to activate the wellbore tool, wherein a pressure applied to the tubing string to cause the indexing mechanism to punch the opening in the device is lower than the one or more test pressures.   
     
     
         81 . The method of  claim 80 , further comprising configuring the indexing mechanism prior to installing the wellbore tool such that the indexing pressure is at least a hydrostatic pressure at a location in the wellbore where wellbore tool is to be installed. 
     
     
         82 . The method of  claim 80 , wherein the device comprises a rupture disk. 
     
     
         83 - 88 . (canceled)