DEVICE FOR WELL WATERPROOFING Russian patent published in 2007 - IPC E21B33/13 

FIELD: oil and gas production industry, particularly methods or devices for cementing, for plugging holes, crevices, or the like.

SUBSTANCE: device comprises pipe string with shoe. The shoe is made as hollow bush with conical lower surface, which may perform limited sliding upwards with respect to pipe string. Hollow bush is provided with self-sealing collar arranged from outer side thereof and with shank having technological groove on outer side thereof and with anchoring unit. The anchoring unit is made as cup, which may slide in axial direction with respect to the shank and provided with centrators. The centrators have friction members and pins cooperating with technological groove. Centrators are spring-loaded outwards. The friction blocks are spring-loaded inwards and provided with guiding means arranged inside friction blocks and inclined towards pipe string axis. The guiding means in their working position may cooperate with conical surface of hollow bush. Lower part of pipe string is provided with bridge. Upper and lower radial channels are arranged below and under the bridge. Lower channels may be closed with hollow bush as it slides upwards.

EFFECT: increased efficiency.

2 dwg