FIELD: soil or rock drilling; mining.
SUBSTANCE: group of inventions relates to well drilling. Device for forming a wellbore in an underground formation comprises a drill bit, a connecting device connected to a drill bit and capable of transmitting torque and axial pressure to a drill bit, a drilling engine driven by fluid medium under pressure, and comprising a stator and a rotor located in the stator and connected to the torque transmission coupling device, an axial pressure generator connected to the rotor and having a pressure surface subjected to pressure of the fluid flowing through the drilling motor, and a power assembly configured to selectively attach the drill motor stator to the borehole wall at the moment of applying the axial pressure to the drill bit.
EFFECT: axial force is provided on the bit when the weight of the drill string is insufficient to support the load on the bit required for efficient drilling of the formation.
16 cl, 4 dwg
