SYSTEM FOR WINDOW CUTTING IN CASING PIPE Russian patent published in 2006 - IPC E21B29/06 

FIELD: mining, particularly to drill additional bores from production strings of quick-acting well or marginal well producer.

SUBSTANCE: system comprises deflecting wedge with guiding surface, mechanical anchor connected to lower deflecting wedge end, milling tool including window milling bit detachably fastened to upper end of deflecting window and two mill-reamers located above window milling bit along well bore. Window milling bit is provided with widened section formed in upper part thereof. Deflecting wedge has ledge, which may cooperate with widened section of window milling bit during casing pipe cutting operation. Milling bit has replaceable blades reinforced with hard alloy and/or cutting inserts. Mill-reamers are connected one to another through flexible connection pipe by means of bi-buttress tool-joint thread and have body sections of reduced diameter. Mill-reamer diameters increase by one standard size in upward direction from window milling bit.

EFFECT: reduced wear of cutting surfaces, increased service life, improved efficiency of metal cuttings removal with flushing liquid, reduced number of operations necessary for tool replacement and decreased number of trips.

3 cl, 7 dwg