SINGLE-PASS DEVICE WITH WHIPSTOCK FOR FORMATION OF WINDOW IN WELL CASING Russian patent published in 2001 - IPC

FIELD: well drilling equipment lowered into well. SUBSTANCE: device has mining tool secured to upper end of whipstock. Connected to lower end of whipstock is a packer or anchor which may be installed with the help of corresponding means up to disconnection of milling cutter from whipstock. The packer may be hydraulic and installed with the help of installing tool located above milling cutter which has washing windows initially isolated from milling cutter central chamber. Upper end is made in the form of inclined surface whose angle of inclination to well axis is larger than angle of inclination of main surface to well. Place of transition between inclined surface and main deflecting surface is located so that in combination action of end and side cutters of milling tool at moment when leading edge comes off the inclined surface onto main deflecting surface, cutting through of casing takes place. EFFECT: cutting of window for one lowering of tool. 13 cl, 5 dwg