Apparatus for and method of cutting through or deforming a sidewall of a downhole tubular

An apparatus for cutting through or deforming a sidewall of a downhole tubular, the apparatus comprising:

• a housing having a cylinder provided therein:
• at least one radially moveable body member having a contact surface formed on an outer surface thereof;
• wherein the body member is located within and is radially moveable within the cylinder such that the contact surface is moveable between a retracted position and an extended position for at least contacting the inner surface of a throughbore of a downhole tubular,
• wherein the contact surface comprises an arc length which extends, from end to end, in the range of 45° and 72°;
• wherein the body member comprises a piston;
• wherein the housing comprises a fluid chamber defined by at least one inner surface of the cylinder and an innermost face of the piston;
• wherein the housing further comprises a fluid port to permit fluid to flow into and out of said fluid chamber;
• wherein the apparatus further comprises:—
• a separate fluid reservoir in fluid communication with said fluid chamber;
• and
• a hydraulic actuator tool configured to introduce fluid into the fluid chamber from said separate fluid reservoir and withdraw fluid from the fluid chamber into said separate fluid reservoir;
• wherein, by operation of the hydraulic actuator tool, the body member is radially moveable from the retracted position to the extended position by introduction of fluid, from said separate fluid reservoir, through said fluid port and into said fluid chamber;
• and
• wherein, by operation of the hydraulic actuator tool, the body member is radially moveable from the extended position to the retracted position by withdrawal of fluid through said fluid port from said fluid chamber, through said fluid port and into said separate fluid reservoir;
• and
• wherein the apparatus has a longitudinal axis and is adapted to be rotated within the throughbore of the downhole tubular about said longitudinal axis such that the contact surface remains on the same circumferential plane.