DRILLING METHOD OF OFFSHOOT OF OIL WELL Russian patent published in 2019 - IPC E21B7/04 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the field of oil and gas wells offshoots drilling. Method of drilling of offshoot of oil well includes continuous cutting of interval of production string and cement stone of cylindrical shape, installation in the main hole of the temporary cement bridge below the point of sidetracking of the offshoot, isolation of the expansion interval by installation of the easily drilled insert from soft metal of cylindrical shape with length more than the length of the cutting interval, in upper part of which there is channel for pumping into expansion interval of hardening sealing compound and central channel, from above closed by easily breakable membrane, pumping into the expansion interval hermetic composition, drilling after its polymerization of an easily drilled insert with a milling cutter, the lower end of which is equipped with a guide of cylindrical shape with diametrical size, allowing to move inside the central channel and upper part is equipped with centralizers, installation of wedge-deflector, drilling of side barrel through hardened tight composition, drilling of side barrel from main, opening of main shaft by drilling wedge-diverter and temporary cement bridge, wherein continuous cutting of the production string and cement stone interval is cylindrical over the entire length, the easily drilled insert is installed on the temporary cement bridge, drilling of easily drilled insert is performed by cutter, length of guide of cylindrical shape has length less than thickness of cement bridge, and diameter of central channel above membrane is greater than diameter of central channel below membrane, wedge-deflector is installed on surface of cement bridge.

EFFECT: higher reliability of easily drilled insert and manufacturability of offshoot cutting.

1 cl, 7 dwg