Wellbore apparatus for setting a downhole tool

1. A method of separating a downhole tubular, the method comprising:

running a tool into a wellbore to a predetermined location on a work string;

actuating flow-actuated slips;

maintaining the flow-actuated slips in a set position by providing a first upward force on the work string;

rotating the work string to separate an upper portion of the tubular from a lower portion using a cutter assembly disposed on the work string below the flow-actuated slips;

maintaining a packer assembly in an unset position on the tool using a locking system in a locked position; and

pulling the upper portion of the tubular and the tool from the wellbore.

2. The method of claim 1 , wherein the pulling of the upper portion of the tubular and the tool from the wellbore unlocks the packer assembly of the tool.

3. The method of claim 2 , wherein the packer assembly is then moved to a second set position in the wellbore.

4. The method of claim 3 , wherein the packer assembly is set in the second set position by a second upward force on the work string, the second upward force being greater than the first upward force.

5. The method of claim 1 , wherein actuating the flow-actuated slips comprises pumping a working fluid through the work string, wherein a port located in a wall of a mandrel of the tool permits the working fluid to travel between the work string and the flow-actuated slips.

6. The method of claim 1 , wherein, in response to pulling the upper portion of the tubular and the tool from the wellbore, the method further comprises:

determining that the upper portion of the tubular cannot be lifted from the wellbore;

unlocking the locking assembly and setting the packer assembly;

clearing debris by flowing fluid through the work string and into an annular area between the tubular and the wellbore therearound; and

pulling the upper portion of the tubular and the tool again from the wellbore.

7. The method of claim 6 , wherein flowing the fluid through the work string and into the annular area further comprises:

creating a barrier below the tool;

trapping the fluid between the barrier and the packer assembly of the tool; and

providing an additional lifting force on the upper portion of the tubular by pumping the fluid pressurized between the barrier and the packer assembly.

8. The method of claim 7 , wherein creating the barrier below the tool comprises:

setting a lower packer below the cutting tool to trap the fluid between the lower packer and the packer assembly of the tool; or

using a cement plug previously placed in the wellbore to create the barrier below the tool.

9. The method of claim 6 , wherein pulling the upper portion of the tubular and the tool again from the wellbore comprises lifting the tool, the cutting tool, and the upper portion of the tubular with the flow-actuated slips and the packer assembly remaining set.

10. The method of claim 6 , wherein, in response to pulling the upper portion of the tubular and the tool again from the wellbore, the method further comprises:

determining that the upper portion of the tubular cannot be dislodged and raised; and

repositioning the tool and the cutting tool at another location on the tubular to separate another upper portion of the tubular.

11. The method of claim 10 , wherein repositioning the tool and the cutting tool comprises:

unsetting the flow-actuated slips and the packer assembly by reducing a lifting force on the work string;

resetting the locking system of the packer assembly;

returning the packer assembly to the unset position with the locking system reset; and

releasing the flow-actuated slips and urging the flow-actuated slips to a run-in position by applying additional downward movement.

12. The method of claim 11 , wherein after repositioning, the method comprises resetting the flow-actuated slips, unlocking the locking system of the packer assembly, and setting the packer assembly.

13. The method of claim 6 , wherein pulling the upper portion of the tubular and the tool from the wellbore comprises:

applying a second upward force on the work string to unlock and set the packer assembly, the second upward force being greater than the first upward force;

flowing fluid through the work string and into an annular area between tubular and the wellbore therearound, the annular area accessible through a cut formed between the upper and lower portions by the cutter assembly;

reducing the second upward force on the work string to unset and re-lock the packer assembly; and

pulling the upper portion of the tubular from the wellbore.

14. The method of claim 6 ,

wherein maintaining the packer assembly in the unset position on the tool using the locking system in the locked position comprises preventing axial movement between displaceable members of a collet sleeve having a collet housing disposed therearound; and

wherein unlocking the locking assembly comprises moving the locking system from the locked position to an unlocked position in which axial movement between the displaceable members is permitted and in which the displaceable members of the collet sleeve are displaced.

15. The method of claim 14 , wherein the displaceable members each include a tab formed on an outer surface thereof, each tab including a lower tab angle; and wherein the collet housing includes an upset formed on an inner surface thereof, the upset including an upper angled surface constructed and arranged to matingly contact the lower tab angles of the displaceable members in the locked position.

16. The method of claim 15 , wherein moving the locking system from the locked position to the unlocked position comprises applying enough upward movement of the collet housing relative to the collet sleeve for the upper angled surface of the upset to move past the lower tab angles, thereby deflecting the displaceable members inwards a first distance and permitting axial movement between the collet sleeve and the collet housing.

17. The method of claim 15 , wherein after the system is unlocked, the displaceable members are deflected a second additional distance.

18. The method of claim 17 , wherein movement from the locked to the unlocked position requires a first higher force and movement from the unlocked to the locked position requires a second lesser force.

19. A method of separating a downhole tubular, the method comprising:

running a tool into a wellbore to a predetermined location on a work string;

actuating flow-actuated slips;

maintaining the flow-actuated slips in a set position by providing a first upward force on the work string;

rotating the work string to separate an upper portion of the tubular from a lower portion using a cutter assembly disposed on the work string below the flow-actuated slips;

applying a second upward force on the work string to unlock and set a packer, the second upward force being greater than the first upward force;

flowing fluid through the work string and into an annular area between the tubular and a borehole therearound, the annular area accessible through a cut formed between the upper and lower portions by the cutter assembly;

reducing the second upward force on the work string to unset and re-lock the packer; and

pulling the upper portion of the tubular from the wellbore.

20. The method of claim 19 , wherein the flow-actuated slips are actuated by pumping a working fluid through the work string, wherein a port located in a wall of a mandrel of the tool permits the working fluid to travel between the work string and the flow-actuated slips.

21. A locking system for a downhole tool, the locking system comprising:

a first portion including a collet sleeve having a plurality of displaceable members,

a second portion disposed around the first portion, the second portion including a collet housing; a locked position wherein axial movement between the members is prevented; and an unlocked position wherein axial movement between the members is permitted and wherein the displaceable members of the collet sleeve are displaced in the unlocked position, the displaceable members each including a tab formed on an outer surface thereof, each tab including a lower tab angle and the collet housing including an upset formed on an inner surface thereof, the upset including an upper angled surface constructed and arranged to matingly contact the lower tab angles of the displaceable members in the locked position.

22. The locking system of claim 21 , wherein moving the system from the locked to the unlocked position requires enough upward movement of the second portion relative to the first position for the upper angled surface of the upset to move past the lower tab angles, thereby deflecting the displaceable members inwards a first distance and permitting axial movement between the sleeve and the housing.

23. The locking system of claim 22 , wherein after the system is unlocked, the displaceable members are deflected a second additional distance.

24. The locking system of claim 23 , wherein movement from the locked to the unlocked position requires a first higher force and movement from the unlocked to the locked position requires a second lesser force.