Patent Application

App. No. 13/901,785

Abstract

Claims (38)

1 . A retrievable stimulation frac plug for a well casing, comprising:

an elongate mandrel having a fluid bore;

a valve seat, adapted to receive a sealing member for selectively sealing the fluid bore;

a sealing mechanism for releasably sealing between the mandrel and the well casing;

a slip mechanism for releasably engaging the well casing; and

a valve seat bypass, moveable between a closed position and an open position, adapted to selectively provide a bypass past the valve seat.

2 . The retrievable stimulation frac plug of claim 1 , the valve seat bypass comprising a bypass sleeve extending along the mandrel, the mandrel having bypass port, and the bypass port sealed when the bypass sleeve is in a closed position, and the bypass port open when the bypass sleeve is in an open position.

3 . The retrievable stimulation frac plug of claim 2 , further comprising a shear pin for retaining the bypass sleeve in the closed position.

4 . The retrievable stimulation frac plug of claim 2 , wherein the bypass sleeve extends around the outside of the mandrel.

5 . The retrievable stimulation frac plug of claim 2 , wherein the valve seat is a ball seat.

6 . The retrievable stimulation frac plug of claim 2 , wherein the sealing member is a ball.

7 . The retrievable stimulation frac plug of claim 1 , further comprising a lower retrieval tool, the lower retrieval tool proximate a downhole end of the retrievable stimulation frac plug, wherein the lower retrieval tool is adapted to engage a lower stage retrievable stimulation frac plug.

8 . The retrievable stimulation frac plug of claim 7 , the lower retrieval tool comprising:

a retrieval sleeve, adapted to fit over the valve seat of the lower stage retrievable stimulation frac plug, providing a lower circulation passage between the lower retrieval tool and the lower stage retrievable stimulation frac plug;

a bypass actuator adapted to move a lower stage bypass sleeve into an open position to open a lower stage bypass port through a lower stage mandrel of the lower stage retrievable stimulation frac plug; and

a lower connector, adapted to engage an upper connector of the lower stage retrievable stimulation frac plug.

9 . A method of conducting a well operation in a well casing, comprising:

a. providing a retrievable stimulation frac plug having:

an elongate mandrel having a fluid bore;

a valve seat, adapted to receive a sealing member for selectively sealing the fluid bore;

a sealing mechanism for releasably sealing between the mandrel and the well casing;

a slip mechanism for releasably engaging the well casing; and

a valve seat bypass, moveable between a closed position and an open position, adapted to selectively provide a bypass past the valve seat;

b. locating and setting the retrievable stimulation frac plug in the well casing;

c. sealing the fluid bore; and

d. conducting a well operation in the well casing above the retrievable stimulation frac plug.

10 . The method of claim 9 , the sealing the fluid bore comprising providing a ball into the valve seat to seal the fluid bore.

11 . The method of claim 9 , the well operation comprising perforating the well casing or frac-stimulation of a formation adjacent the well casing or both.

12 . The method of claim 9 , further comprising repeating (a), (b), (c), and (d) for an additional number (n−1) of stages for a total number (n) stages.

13 . The method of claim 12 , further comprising:

a. providing a retrieval tool having a lower connector adapted to engage the stage n retrievable stimulation frac plug and actuate the valve bypass;

b. deploying the retrieval tool to engage the stage n retrievable stimulation frac plug actuate the valve bypass;

c. releasing the sealing mechanism and the slip mechanism of the stage n retrievable stimulation frac plug;

d. moving the retrieval tool and the stage n retrievable stimulation frac plug down the well casing towards a stage n−1 retrievable stimulation frac plug, such that the lower retrieval tool of the stage n retrievable stimulation frac plug engages the stage n−1 retrievable stimulation frac plug.

14 . The method of claim 13 , further comprising circulating fluid through the circulation passage and through the fluid bore of the stage n retrievable stimulation frac plug prior to and/or while engaging the stage n−1 retrievable stimulation frac plug.

15 . The method of claim 13 , further comprising retrieving at least the stage n retrievable stimulation frac plug and the stage n−1 retrievable stimulation frac plug out of the well casing in a single run.

16 . The method of claim 13 , further comprising retrieving at least five retrievable stimulation frac plugs in a single run.

17 . The method of claim 13 , further comprising retrieving substantially n retrievable stimulation frac plugs in a single run.

Assignments (9)