WELL DRILLING METHOD Russian patent published in 2015 - IPC E21B21/00 E21B7/00 

FIELD: oil and gas industry.

SUBSTANCE: method includes the rotation and axial delivery of an assembly with a bit and supply of a flushing fluid through an inner cavity of the assembly to the bottomhole, in the flushing fluid loss zone the transfer of the fluid supply to an annular space over the downhole motor through the cross-over shoe by its activating. At the transfer of the fluid supply in the flushing fluid loss zone the isolating compound is supplied at a pressure of 2-6 MPa, flow rate of 8-12 l/s in a volume of 10-30 m³, upstream the injection volume drilling mud is placed, the assembly is put up to the drilling mud zone, pressure up to 3 MPa is generated in the annular space, the isolating compound is flushed to the loss zone in the full volume, the process is withhold until the isolating compound is set and hardened, the cross-over shoe is deactivated, circulation is restored and injection capacity is defined. If the injection capacity is less than 2 m³/h the drilling process is renewed.

EFFECT: increased efficiency of isolation for the flushing fluid loss zones at well drilling.