Patent ID: 6581690
Filing Date: 2003-06-24
Classification: E21B

Abstract:
A downhole well casing window cutting tool for use in milling a window in a wall of a well casing, said tool comprising a milling bit provided with a positioning device, said device comprising at least one elongate longitudinally extending well casing engagement member mounted on a body at a first side of said body, which body is disposable, in use of the device, in-line with a drill string, so as to be movable relative to said body between a retracted position and a generally radially outwardly displaced position for well casing engagement at said first side of said body in use of the device, each said at least one engagement member having pressurised-fluid operable actuator means formed and arranged for driving said at least one well casing engagement member between said retracted and well casing engagement positions, said device including pressurised fluid supply means formed and arranged for controlling the supply of pressurised fluid, in use of the device, to said actuator means for operation thereof, whereby in use of the device said milling bit may be displaced laterally relative to the central longitudinal axis of the well casing in which said milling bit is disposed, into engagement with the well casing at a second side of said body opposite to said first side, by operation of said actuator means.