Downhole tools, systems and methods of using

1. A downhole tool having an exterior, the tool comprising:

a nested sleeve assembly comprising a shifting sleeve, the shifting sleeve having a first position and a second position;

an indexing assembly in communication with the shifting sleeve, the indexing assembly having an actuated position and at least one non-actuated position;

a pressure sleeve moveable in response to fluid pressure in an interior flowpath of the tool;

a fluid control device; and

a spring;

wherein, the indexing assembly advances from the at least one non-actuated position to the actuated position in response to a predetermined stimulus;

the indexing assembly prevents the nested sleeve from moving to the second position when the indexing assembly is in the at least one non-actuated position;

the spring opposes movement of the pressure sleeve towards the fluid control device;

the fluid control device is slidable relative to the pressure sleeve in a first direction and fixed relative to the pressure sleeve in a second direction substantially opposite to the first direction; and

movement of the pressure sleeve in the second direction moves the fluid control device towards an actuated position.

2. The downhole tool of claim 1 wherein the spring opposes movement of the pressure sleeve in the first direction.

3. The downhole tool of claim 1 wherein the indexing assembly comprises a fluid control device.

4. The downhole tool of claim 1 wherein the indexing assembly comprises at least one ratchet assembly.

5. The downhole tool of claim 4 , wherein the at least one ratchet assembly comprises collet fingers having teeth thereon and a sliding sleeve comprising a rack for engaging the teeth.

6. The downhole tool of claim 1 wherein the shifting sleeve remains in the closed position until the indexing assembly reaches the actuated position.

7. A method for actuating a downhole tool, the method comprising

flowing a fluid into the downhole tool, the downhole tool comprising:

a nested sleeve assembly having a shifting sleeve and a passageway connecting at least one surface of the shifting sleeve with a flowpath of the downhole tool, the shifting sleeve having a first position and a second position;

an indexing assembly comprising a pressure sleeve with an advanced position and a neutral position, a spring, and a fluid control device; the pressure sleeve engaged with the fluid control device when moving in a first direction and not engaged with the fluid control device when moving in a second direction substantially opposite the first direction;

applying a fluid pressure cycle to the fluid in the downhole tool; the pressure cycle comprising a high pressure on the fluid sufficient to move the pressure sleeve and compress the spring a desired amount and a low pressure on the fluid permitting the spring to return the pressure sleeve to a neutral position;

moving the pressure sleeve and the fluid control in the first direction during the pressure cycle;

moving the pressure sleeve in the second direction during the pressure cycle, thereby advancing the indexing assembly

repeating the pressure cycle until the fluid control device is moved from a closed position to an open position in response to the plurality of pressure cycles.

8. The method of claim 7 further comprising flowing cement through tool before the first of said plurality of pressure cycles.

9. The method of claim 7 further comprising conducting a pressure test before the fluid control device reaches the open position, wherein the pressure of the fluid in the interior flowpath is increased to a pressure at least as high as a maximum treating pressure predicted to be applied for treating a well within which the downhole tool is placed.

10. A downhole tool having an exterior, the tool comprising:

a nested sleeve assembly comprising a shifting sleeve, the shifting sleeve having a first position and a second position; and

an indexing assembly in communication with the shifting sleeve, the indexing assembly having an actuated position and at least one non-actuated position and at least one ratchet assembly, the ratchet assembly comprising collet fingers having teeth thereon and a sliding sleeve with a rack for engaging the teeth;

wherein the indexing assembly advances from the at least one non-actuated position to the actuated position in response to a predetermined stimulus; and

further, wherein the indexing assembly prevents the nested sleeve from moving to the second position when the indexing assembly is in the at least one non-actuated position.

11. The downhole tool of claim 10 wherein the indexing assembly comprises

a pressure sleeve moveable in response to fluid pressure in an interior flowpath of the tool,

a fluid control device,

a spring,

wherein

the spring opposes movement of the pressure sleeve towards the fluid control device

the fluid control device is slidable relative to the pressure sleeve in a first direction and fixed relative to the pressure sleeve in a second direction substantially opposite to the first direction;

movement of the pressure sleeve in the second direction moves the fluid control device towards an actuated position; and

the spring opposes movement of the pressure sleeve in the first direction.

12. The downhole tool of claim 10 wherein the indexing assembly comprises a fluid control device.

13. The downhole tool of claim 10 wherein the shifting sleeve remains in the closed position until the indexing assembly reaches the actuated position.

14. The downhole tool of claim 10 wherein advancing of the indexing assembly comprises movement of the collet fingers along the rack.