| CPC E21B 7/046 (2013.01) [E21B 7/061 (2013.01); E21B 29/06 (2013.01)] | 19 Claims |
|
1. A sidetracking method, comprising:
lowering a sidetrack assembly to a target zone of a wellbore comprising a casing, the sidetrack assembly comprising a cutting tool coupled to a downhole end of a wellbore string and a whipstock releasably coupled to a downhole end of the cutting tool, the cutting tool comprising a movable cutter and movable mechanical fasteners;
setting the whipstock on a wall of the wellbore, fluidly isolating the target zone from a section of the wellbore downhole of the whipstock;
pulling, in an uphole direction, the wellbore string, decoupling the cutting tool from the whipstock;
actuating the cutter, cutting along a cut profile of the casing to cut free a portion of the casing at the target zone, the cutter comprising a rotatable blade coupled to an arm movable by a controller operatively coupled to the arm, the actuating comprising moving, by the controller, the arm to move the blade along the cut profile of the casing;
actuating the mechanical fasteners to fasten, with the mechanical fasteners, the portion of the casing to the cutting tool;
pulling, in an uphole direction and with the mechanical fasteners fastened to the portion of the casing, the wellbore string, detaching the portion of the casing from the wall of the wellbore with the mechanical fasteners and forming a window in the casing;
removing the portion of the casing from the wellbore by pulling the wellbore string and cutting tool out of the wellbore, with the portion of the casing attached to the cutting tool;
drilling, after removing the portion of the casing from the wellbore and with a directional drill string guided by the whipstock, a sidetrack wellbore extending from the window to a downhole location of the sidetrack wellbore; and
removing, by the wellbore string or a second wellbore string, the whipstock from the wellbore.
|