DEVICE FOR STAGE CEMENTING OF CASING STRINGS Russian patent published in 2016 - IPC E21B33/14 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry and is intended for stage cementing of casing strings in wells. Device includes housing with holes. Bushings with shear elements are connected to housing. There is trunk in axial channel of housing with formation of annular chamber, hydraulically connected with axial channel of trunk. Trunk is made with stepped bore. It incorporates mounting bushing with inner circular ledge, pressed with nut, and sleeve with upper collet with lobes. Their heads are arranged inside the circular ledge of mounting bushing. There is lower collet with lobes and barrel with valve seat in axial channel. Barrel is installed in axial channel of sleeve to rest on circular ledge of lower collet lobes. There is stepped shutter with external circular ledge, equipped with seat installed inside the barrel to interact with heads of upper collet lobes. In annular chamber there is seating mechanism in form of annular bushing and hollow rod. At rod lower end there is expanding cone with retaining ring. Trunk is equipped with nut and extrusive washer, and package of sealing cuffs. In barrel there are bypass holes, aligned with holes in sleeve body and circulation holes in trunk. Annular chamber is hydraulically connected through radial holes in housing with annular space of well.

EFFECT: technical result is possibility to release device channel without drilling.

1 cl, 3 dwg