DEVICE FOR INTERVAL COVERING OF TROUBLE ZONES AT WELL DRILLING Russian patent published in 2012 - IPC E21B29/10 

FIELD: machine building.

SUBSTANCE: device includes covering unit consisting of sections of shaped tubes with cylindrical ends, expanding mechanism with roll-forming head, equipped with connection assembly to drill pipes at the top and to the top of covering unit from below; head with cutting elements and shoe with non-return valve from below the covering unit; at that, upper and lower cylindrical ends of covering unit are extended with the corresponding cylindrical sleeves with wall thickness equal to the half of wall thickness of shaped tubes; at that, plug from easily drilled material with longitudinal holes is inserted into lower sleeve from below, and roll-forming head is equipped from below with hollow tip with end projections, inside which a groove for spring rings is made; at that, head with cutting elements is located from below the shoe that is equipped from above with longitudinal grooves or holes for projections of the tip and catching head with upper thickening, which can enter the tip and interact with spring ring engaged with upper thickening at interaction. External cylindrical grooves are made on upper sleeve and internal cylindrical grooves are made on lower sleeve.

EFFECT: higher reliability and quality of covering.

3 dwg