Downhole tubing shift tool and method

1. In a wellbore comprising production tubing extending from the earth surface into a production strata beneath the earth surface and an indexing deflector assembly that has a deflector shoe directing a milling or drilling tool laterally of a longitudinal axis of the production tubing and is mounted for axial reciprocation within the wellbore and an indexing device connected to the deflector shoe to rotate the deflector shoe about a longitudinal axis of the production tubing when the deflector shoe is raised and lowered in the well bore; wherein the indexing deflector assembly is connected to the production tubing in a downhole section of the wellbore distant from earth surface; and a shift tool assembly connected between the downhole device and a portion of the production tubing, the shift tool assembly is configured to sequentially lift and lower the deflector shoe relative to an upper portion of the production tubing to change the radial position of the deflector shoe.

2. The wellbore of claim 1 , wherein the shift tool assembly is responsive to pressurized fluid delivered from the surface to lift the deflector shoe.

3. The wellbore of claim 2 , wherein the shift tool assembly has an upper portion that is connected to the production tubing, and has a movable fluid-delivery part that is mounted for longitudinal movement with respect to the production tubing.

4. The wellbore of claim 3 , wherein the fluid-delivery portion is operatively connected to a fluid conduit that carries pressurized fluid to the fluid-delivery device.

5. The wellbore of claim 3 , wherein the shift tool assembly has a sub part that comprises outer and inner hollow tubular portions defining a variable volume fluid chamber between them, the outer portion is movable relative to the inner portion, the inner portion is connected to the upper production tubing and the outer portion is connected to the downhole device, and the inner portion comprises a fluid path communicating with the variable volume chamber and with the fluid-delivery tool when the fluid-delivery tool is in operative contact with the shift tool.

6. The wellbore of claim 3 , wherein the sub part comprises a fluid release portion, and the fluid-delivery portion comprises a fluid-release device activated by the fluid release portion when the fluid-delivery portion is in operative contact with the sub part.

7. The wellbore of claim 6 , wherein the fluid release portion comprises a bore, and the fluid-release device comprises a check valve.

8. The wellbore of claim 1 , wherein the shift tool assembly has parts that are movable between an extended and a retracted position.

9. The wellbore of claim 1 wherein the shift tool is connected directly to the deflector shoe.

10. The wellbore of claim 1 , wherein the shift tool is connected to the deflector shoe through a lower portion of production tubing.

11. A method for controlling reciprocation of a deflector shoe in an indexing deflector assembly that is connected to production tubing in a downhole section of a wellbore distant from a surface location comprising:

providing a shift tool comprising a pair of hollow cylinders that define between them a variable volume fluid chamber;

placing the shift tool between the deflector shoe and an upper portion of the production tubing;

introducing fluid pressure to the variable volume fluid chamber of the shift tool to raise the deflector shoe without raising and lowering the upper portion of the production tubing; and

subsequent to the act of introducing fluid pressure to the variable volume fluid chamber, releasing fluid pressure from the variable volume fluid chamber to lower the deflector shoe without raising and lowering the upper portion of the production tubing.

12. The method of claim 11 wherein the introducing act comprises the applying fluid pressure from the surface location to the shift tool.

13. A shift tool apparatus for use in a well bore in which production tubing extends from the earth surface into a production strata beneath the earth surface and a downhole device is connected to the production tubing in a downhole section of the wellbore distant from earth surface and the downhole device is configured with a part that is axially shiftable with respect to another part that is fixed within the wellbore for axial reciprocation within the wellbore, the shift tool apparatus comprising:

a hollow tubular sub comprising inner and outer hollow tubular cylinders mounted for reciprocal telescoping movement between a retracted position and an extended position, a fluid-delivery device; and a bottom sub fitting;

the two hollow tubular cylinders form a sealed variable volume fluid chamber between them and a port in the inner tubular cylinder;

the fluid delivery device is configured to mount to an end of a fluid delivery tubing at an open end and to move axially within the inner tubular cylinder, and further has an internal fluid path including the open end with a fluid release port that is selectively closed by a releasable valve;

the bottom sub fitting is mounted to the outer tubular cylinder and is configured to receive a lower end of the fluid delivery device and further is configured to open the releasable valve in the fluid delivery device to open the fluid release port when the fluid delivery device is received in the bottom sub fitting; and

wherein the fluid release port is in communication between the inlet opening in the inner tubular cylinder to pressurize the variable volume fluid chamber to move the inner and outer cylinders from the extended position to the retracted position.

14. The shift tool apparatus of claim 13 and further comprising axially spaced seals between fluid delivery device and the inner tubular surface and the fluid release port is positioned between the spaced seals.

15. In a wellbore comprising production tubing extending from the earth surface into a production strata beneath the earth surface and a downhole device that is mounted for axial reciprocation within the wellbore wherein the downhole device is connected to a lower portion of the production tubing in a downhole section of the wellbore distant from earth surface, a shift tool apparatus according to claim 13 wherein the hollow tubular sub is mounted between a lower portion of the production tubing and the downhole device, and the fluid delivery device is mounted to a lower end of a moveable fluid-delivery tubing that extends down from the earth surface to the hollow tubular sub.

16. The wellbore of claim 15 wherein the outer hollow tubular cylinder is mounted to the downhole device and the inner hollow tubular cylinder is mounted to the production tubing.

17. The wellbore of claim 15 wherein the downhole device is an indexing deflector assembly that has a deflector shoe directing a milling or drilling tool laterally of a longitudinal axis of the production tubing and an indexing device connected to the deflector shoe to rotate the deflector shoe about a longitudinal axis of the production tubing when the deflector shoe is raised and lowered in the well bore.