METHOD FOR CREATING DEPRESSION ON FORMATION WITH WELL ROTOR DRILLING Russian patent published in 2017 - IPC E21B21/08 E21B7/00 

FIELD: mining engineering.

SUBSTANCE: method includes flushing the well with the surface pump through the drill piping string, transferring the axial load and torque to the bit and deepening the well, regular suspending the well deepening, sealing the annulus with a rotating packer, mounted on the cylindrical body, activating the reverse bottomhole flushing with the fluid pressure drop on the packer, created with the jet pump, installed above the packer at the lower end of the drill string and configured as a nozzle, a mixing chamber and a diffuser, hydraulically connected to the annulus, and resuming to depeen with the formation depression. The transmission of axial load and torque to the bit is carried out directly through cylindrical body, made to be sealed over the outer surface, which is moved during well deepening along the entire length with rotation inside the packer, with small allowable leakage of fluid between the mating surfaces, using a combined metal ring seal, installed first in the course of the leak, and a rubber element installed second in the course of the fluid leakage in the region of reduced pressure and hydraulically bound thereof internal cavity to the high pressure annulus above the packer. The packer is provided with a mechanical lock. The cylindrical body in the lower part is provided with a return valve and is made in the form of one drill pipe or several pipes with a diameter of joints of the latter equal to the diameter of the pipe body with the total length of the cylindrical body not more, than the length of the used candles.

EFFECT: efficiency of the method is increased by reducing the contamination of the formation and ensuring drilling in one configuration for depression and repression.

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