EXPANDABLE PIPE SYSTEM WITH PRE-FLUSHING FOR ISOLATION OF ZONES OF COMPLICATIONS DURING DRILLING OF WELLS Russian patent published in 2020 - IPC E21B29/10 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry, namely to devices for isolation of zones of complications, in particular, crumbling and falls at drilling of wells. Device includes shaped shutter, shaped tubes with five and more beams with cylindrical sections, installed on lower end of shutter easily drilled shoe with seat of check valve and calibrated hole for creation of pressure drop during expansion of shaped pipes and release of ball installed inside shaped pipes and released when exceeding selected pressure drop and tightly closing back valve seat, expanding roller underreamer equipped from below with cutter with rollers for preliminary calibration of narrow sections of shaped pipes after their expansion by hydraulic pressure and drilling of shoe. Underreamer with the shutter is connected by a right-hand thread. Spring-loaded valve is arranged in central channel below seat of check valve to shut off central channel at preliminary expansion of shaped pipes. Calibrated hole for creation of pressure drop at preliminary expansion of profile pipes is equipped with an additional spring-loaded valve. Ball is installed in transition section between cylindrical section and shaped one. Filter and an upper valve communicating the annular space and the in-pipe line when the shutter is lowered into the well is installed above the underreamer, and overlapping the annular space when internal pressure of the liquid is created.

EFFECT: excluding ingress of slurry into profile shutter both at filling and at its expansion by hydraulic pressure; direct flushing of the well is provided for removal of slime at the installation site.

1 cl, 2 dwg