DEVICE FOR CLOSING TROUBLESOME ZONE IN WELL-DRILLING Russian patent published in 2010 - IPC E21B29/10 

FIELD: oil and gas production.

SUBSTANCE: device comprises a shutter consisting of sections of shaped tubes soldered in profile end faces, with cylindrical sites on the thread-connected ends, a flaring device with a rolling head mounted over a shaped shutter and having an assembly joint with drill pipes from the top and with the shutter from beneath. On the lower end of the shutter, there is a bearing plate with a return valve; the flaring device below the assembly joint with the shutter is provided with a head with elements interacting with the bearing plate at its top. The assembly joint with the shutter is represented by a cylindrical case with upper and lower supports on its surface the lower of which is designed to perform longitudinal motions downwards to be fixed in extreme position, and the support is provided with the rams interacting with the support to perform radial motion, and the rams of the upper and lower supports are sequenced around the cylindrical case and equipped with respectively interacting inclined surfaces designed to reduce the diametre of circumscribed circle while traveling downwards of the lower support, and the rams in their maximum diametre of circumscribed circle are designed to be fixed inside of the shutter.

EFFECT: higher reliability, reduced expenses.

2 dwg