METHOD OF BOTTOMHOLE CLEANING Russian patent published in 2018 - IPC E21B37/00 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry and is used for wellbore cleanout during well workover and reconditioning, in particular at a landed downhole motor. While carrying out the process, a pump provides a liquid flow through the pipe column, the top sub, the through bores in the power section, the middle transfer, spindle and lower transfer sections of the downhole drilling motor into the bottomhole, then the pump is connected to the drill string-borehole annulus and the reverse circulation of fluid from the bottomhole is performed, with which the removed substance is washed away, after which a blocking element is introduced into the pipe column and the pump is turned on, wherein the blocking element with the liquid flow is delivered to the power section of the downhole drilling motor that covers the through bore in the rotor. In this case, the liquid flow is directed between the helical rotor surface and the helical surface of the elastomeric stator insert, between the middle sub and its body, then through the through bore in the spindle, the power section of the downhole drilling motor is activated and the torque from the rotor is transmitted through the sub, spindle and lower sub to the bit, destroying the wellbore skin, and then the pump is reconnected to the drill string-borehole annulus and the reverse circulation is performed. Blocking element, together with the liquid and the substance to be removed, is withdrawn from the through bore in the rotor and through the upper sub and the pipe column is delivered to the wellhead and removed.

EFFECT: required number of cycles of technological operations to clean the bottomhole and the total time of repair work on the well are reduced, the consumption of process fluid is minimized.

3 cl, 8 dwg