MILLING TOOL FOR CUTOUT OF WINDOW IN WELL CASING PIPE Russian patent published in 2013 - IPC E21B29/06 

FIELD: oil and gas industry.

SUBSTANCE: tool includes starting, straight-through and calibrating mills-reamers. Cutting plates fixed in the starting mill-reamer are located concentrically relative to central longitudinal axis of a hollow shaft. Cutting plates in the straight-through and calibrating mills-reamers are located with similar eccentricity and opposite on both sides relative to central longitudinal axis of the shaft. Cutting plates fixed in the straight-through mill-reamer and cutting plates fixed in the calibrating mills-reamers are fixed in longitudinal slots of screw blades formed with screw channels. The housing of the calibrating mill-reamer, a hollow shaft of the calibrating mill-reamer and a hollow shaft of the starting and straight-through mills-reamers are made in the form of a single hollow framework. Sum of maximum eccentricities of cutting plates fixed in longitudinal slots of screw blades of the calibrating and straight-through mills-reamers is equal to difference of radii of cutting plates of the calibrating and straight-through mills-reamers relative to their own longitudinal central axes located opposite on both sides relative to central longitudinal axis of the single framework.

EFFECT: increasing service life and improving reliability; preventing accident risk; providing finish milling with smooth edges; improving cutout accuracy of a window in a well casing pipe.

2 cl, 10 dwg