Whipstock retrieving bit

1 . A retrievable whipstock assembly for a wellbore, comprising:

a whipstock comprising a longitudinal body and an anchor connection;

a deflection surface provided on the longitudinal body and having a first engagement element; and

a drilling assembly comprising a drill housing and a second engagement element, wherein the second engagement element is selectively extendible between a recessed position and an extended position;

wherein in the extended position the second engagement element is engageable with the first engagement element,

wherein the first engagement element comprises a slot that extends radially through the deflection surface of the whipstock, and

wherein the drilling assembly further comprises a drill bit.

2 . The retrievable whipstock assembly of claim 1 , wherein the whipstock further comprises a drilling assembly connector releasably connecting the whipstock and the drilling assembly.

3 . The retrievable whipstock assembly of claim 2 , wherein the drilling assembly connector comprises a shear pin.

4 . The retrievable whipstock assembly of claim 1 , wherein the slot has a tapered shape.

5 . The retrievable whipstock assembly of claim 1 , wherein the second engagement element comprises an extendible pad.

6 . The retrievable whipstock assembly of claim 5 , wherein the extendible pad comprises a brim extending about at least a portion of an outer periphery thereof.

7 . The retrievable whipstock assembly of claim 1 , wherein:

the second engagement element is configured to be hydraulically actuated; and

when hydraulic pressure is applied the second engagement element shifts from the recessed position to the extended position.

8 . The retrievable whipstock assembly of claim 7 , wherein the hydraulic pressure is applied by obstructing a fluid flow path in the drill housing.

9 . The retrievable whipstock assembly of claim 8 , wherein a ball obstructs the fluid flow path in the drill housing.

10 . The retrievable whipstock assembly of claim 1 , wherein the second engagement element is configured to be electro-hydraulically actuated.

11 . The retrievable whipstock assembly of claim 10 , further comprising:

an electronics module; and

a valve controlled by the electronics module and configured to supply hydraulic pressure to the second engagement element;

wherein when the electronics module causes the valve to open, hydraulic pressure shifts the second engagement element into the extended position.

12 . The retrievable whipstock assembly of claim 11 , wherein the electronics module comprises a sensor configured to sense an activation device.

13 . A method of installing and retrieving a whipstock in a wellbore, comprising:

deploying the whipstock into the wellbore, the whipstock comprising a first engagement element;

anchoring the whipstock in the wellbore at a setting depth;

drilling a lateral wellbore section with a drilling assembly;

pulling the drilling assembly out of the lateral wellbore section;

extending a selectively extendable second engagement element on the drilling assembly;

engaging the second engagement element with the first engagement element;

applying an upward tension on the whipstock to release the whipstock from the wellbore; and

removing the drilling assembly and the whipstock from the wellbore together, and

wherein the first engagement element comprises a slot that extends radially through a deflection surface of the whipstock.

14 . The method of claim 13 , wherein extending the second engagement element comprises hydraulic actuation.

15 . The method of claim 13 , wherein deploying the whipstock into the wellbore comprises releasably attaching the whipstock to the drilling assembly.

16 . The method of claim 15 , wherein deploying the whipstock into the wellbore further comprises releasing the whipstock by applying weight to the drilling assembly.

17 . The method of claim 13 , wherein deploying the whipstock, drilling the lateral wellbore section, and removing the drilling assembly and the whipstock are completed in a single trip into the wellbore.

18 . A retrievable whipstock assembly for a wellbore, comprising:

a whipstock comprising a longitudinal body and an anchor connection;

a deflection surface provided on the longitudinal body and having a first engagement element; and

a drilling assembly comprising a drill housing and a second engagement element, wherein the second engagement element is selectively extendible between a recessed position and an extended position;

wherein in the extended position the second engagement element is engageable with the first engagement element;

wherein the first engagement element comprises a slot that extends radially through the deflection surface of the whipstock, and

wherein the drilling assembly further comprises a mill bit.