DOWNHOLE MACHINING SYSTEM AND METHOD Russian patent published in 2018 - IPC E21B29/00 

FIELD: soil or rock drilling.

SUBSTANCE: group of inventions refers to a downhole machining system for machining a casing string in a borehole having a wellhead. System comprises a first tool part, having an axial direction and an anchoring section, a second tool part, adapted to rotate and move axially with respect to the first tool part. Second tool part comprises a machining bit that is movable in a direction radial to the axial extension, a first actuator comprising an electric motor for axially moving the second tool part in relation to the first tool part, a second actuator, comprising an electric motor or a hydraulic cylinder for rotating the second tool part in relation to the first tool part, and a third actuator comprising an electric motor for rotating the bit. At least one of the actuators comprises a gear for changing a rotational speed of a rotor of the motor. Bit is designed to move radially in the bit housing and has a sharp and a piston end and is designed to move radially by an electric motor.

EFFECT: technological possibilities of machining are expanded, efficiency is increased.

18 cl, 13 dwg