A mill including a housing having a fluid bypass pathway, a milling feature at a longitudinal end of the housing, a chamber defined by the housing, and a piston disposed in communication with the chamber, the piston defining a fluid passageway initially aligned with the fluid bypass pathway, the piston responsive to pump pressure to move toward the milling feature, the movement misaligning the fluid passageway with the fluid bypass pathway.

A method of removing material from a target is described. The method comprises the steps of providing a tool, the tool having at least one propellant source; pressurising the tool to a pressure higher than the environmental pressure; igniting at least one of the propellant source(s) to form a combustion zone; and directing combustion products generated at the combustion zone along at least one tool flow path. The tool flow path(s) is selectively openable or closable, such that upon exiting the tool flow path(s) the combustion products interact with a target, the interaction causing material to be removed from the target.

A method of removing material from a target is described. The method comprises the steps of providing a tool, the tool having at least one propellant source; pressurising the tool to a pressure higher than the environmental pressure; igniting at least one of the propellant source(s) to form a combustion zone; and directing combustion products generated at the combustion zone along at least one tool flow path. The tool flow path(s) is selectively openable or closable, such that upon exiting the tool flow path(s) the combustion products interact with a target, the interaction causing material to be removed from the target.

A retrievable whipstock assembly for a wellbore includes a whipstock including a longitudinal body and an anchor connection, a deflection surface provided on the longitudinal body with a first engagement element, and a drilling assembly including a drill housing and a second engagement element. The second engagement element is selectively extendible between a recessed position and an extended position. In the extended position the second engagement element is engageable with the first engagement element.

A retrievable whipstock assembly for a wellbore includes a whipstock including a longitudinal body and an anchor connection, a deflection surface provided on the longitudinal body with a first engagement element, and a drilling assembly including a drill housing and a second engagement element. The second engagement element is selectively extendible between a recessed position and an extended position. In the extended position the second engagement element is engageable with the first engagement element.

A method of positioning a bottom hole assembly in a wellbore includes lowering the bottom hole assembly into the wellbore. The bottom hole assembly has a whipstock, a downhole tool, and a cleaning tool having a cleaning element. The method also includes cleaning at least a portion of a wall of the wellbore using the cleaning tool, and activating the downhole tool to engage the cleaned portion of the wall.

A window cutting system includes a whipstock connector, and a window mill selectively rotationally constrained to the whipstock connector. The window mill including an outer surface, an inner surface, a passage defined between the outer surface and the inner surface, and a recess formed in the outer surface. A locking pin is arranged in the recess. A motor arranged in the passage. An actuator is operatively connected between the motor and the locking pin. The motor being selectively activated through a signal to retract the locking pin releasing the window mill from the whipstock connector.

A window cutting system includes a whipstock connector, and a window mill selectively rotationally constrained to the whipstock connector. The window mill including an outer surface, an inner surface, a passage defined between the outer surface and the inner surface, and a recess formed in the outer surface. A locking pin is arranged in the recess. A motor arranged in the passage. An actuator is operatively connected between the motor and the locking pin. The motor being selectively activated through a signal to retract the locking pin releasing the window mill from the whipstock connector.

A system for a downhole tubular includes a tubular having an outer surface and an inner surface. An anchor setting system is disposed in the tubular. The anchor setting system includes a motor system. An anchor assembly is disposed on the tubular. The anchor assembly includes slip and a setting system having a piston assembly. A window cutting system is arranged along the tubular. An actuator extends from the motor system, through the window cutting system, to the piston assembly. The motor system is selectively activated through a signal to deploy the slip.

A system for a downhole tubular includes a tubular having an outer surface and an inner surface. An anchor setting system is disposed in the tubular. The anchor setting system includes a motor system. An anchor assembly is disposed on the tubular. The anchor assembly includes slip and a setting system having a piston assembly. A window cutting system is arranged along the tubular. An actuator extends from the motor system, through the window cutting system, to the piston assembly. The motor system is selectively activated through a signal to deploy the slip.