MILLING TOOL FOR CUTTING OPENING IN WELL CASING STRING Russian patent published in 2010 - IPC E21B29/06 

FIELD: mining.

SUBSTANCE: device includes starting, advance and calibrating mill reamers with cutting plates fixed in them. Starting and advance mill reamers are made in the form of a single hollow housing, and starting, advance and calibrating mill reamers are rigidly fixed on the single hollow shaft. Aligning belt of the single hollow shaft, which is intended to attach the calibrating mill reamer, is provided with eccentricity relative to central longitudinal axis of single shaft. Cutting plates fixed in advance mill reamer are located with eccentricity relative to cutting plates fixed in starting mill reamer. Cutting plates fixed in starting mill reamer are located concentrically relative to central longitudinal axis of single shaft. Cutting plates fixed in advance and calibrating mill reamer are located with equal eccentricity and opposite on both sides relative to central longitudinal axis of single shaft. Housing of calibrating mill reamer is provided with screw channels. Single hollow housing of starting and advance mill reamers is provided with screw channels for advance mill reamer. Cutting plates fixed in advance and calibrating mill reamer are located along central longitudinal axis of single hollow shaft and fixed in longitudinal slots of screw blades.

EFFECT: improving reliability and efficiency of cutting action, preventing accident risk and decreasing the cost of drilling works.

6 cl, 8 dwg