WAY FOR ORIENTED CUTTING OF WINDOWS IN CASING STRING Russian patent published in 2003 - IPC

FIELD: drilling technique, running of oil and gas wells, technology to cut windows in casing strings to drill additional well bores. SUBSTANCE: according to invention oriented cutting of windows in casing string includes sinking-lifting operations with cutting and rock-breaking tool, milling of walls of casing strings, drilling of additional well bores. Window in wall of casing string is cut without any bearing against cement plug or guiding metal wedge with hanging string of drill pipes with use of joint diverter leaning against wall of well only in the course of complete process of window cutting. Spindle of diverter carrying crown mill can turn in specified direction at angle with axis of well required for overrun of crown mill beyond limits of casing string. EFFECT: capability to cut windows in casing strings without setting cement plugs, raised efficiency of wells. 5 cl, 1 5 dwg