EXPANDABLE TUBULAR SYSTEM WITH INTERMEDIATE FLUSHING FOR ISOLATION OF ZONES OF COMPLICATIONS DURING DRILLING OF WELLS Russian patent published in 2019 - IPC E21B29/10 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry, namely to devices for isolation of zone of complication during well drilling. Device includes profile shutter, shaped tubes with five and more beams with cylindrical sections, shoe with check valve seat, installed on lower end of shutter, expanding head, which contains on top a unit for connection with a drill string, a ball released when the specified pressure difference is exceeded and tightly covering the seat of the check valve. Ball is installed in pre-prepared cavity inside shaped tubes, at expansion of which by means of defined pressure drop ball is released. Shoe with check valve seat is easily drilled and has calibrated hole for creation of pressure drop at expansion of shaped tubes and release of ball. Expansion head is made in the form of a sliding roller flare equipped from below with a special cutter with rollers for preliminary calibration of narrow sections of shaped pipes after their expansion by hydraulic pressure and drilling of the shoe. Flare-together with the shutter is connected by a right-hand thread. Upper cylindrical section of the shutter is made so that the distance from the calibrating part of the rollers of the sliding roller to the lower part of the right running thread is less than or equals the distance from the end section of the cutter to the beginning of the shaped part of shaped tubes of the shutter.

EFFECT: increased reliability, possibility of direct flushing of the well for slime removal.

1 cl, 2 dwg