REAMING SHOE Russian patent published in 2020 - IPC E21B37/00 

FIELD: mining.

SUBSTANCE: invention relates to construction of wells and is intended for equipment of casing string bottom for the purpose of its direction along borehole with possibility of development of unstable sections of shaft with zones of crumbling and rock falls. Device includes drilled mandrel with pass channel and screw slots, pins installed rigidly in lower part of housing and movably into slots of mandrel, armed shoe equipped with blades and flushing holes rigidly connected from below with mandrel. In the upper part the mandrel is equipped with a hydraulic nozzle. Housing in middle part is equipped with radial holes, and in upper part - valve in through channel and hydraulic nozzle with seat. Armed shoe, hydraulic nozzles and valve are made of easily drilled material. Square cross-sections of hydraulic nozzles and radial holes of the housing are selected so that when creating a certain flow rate of liquid and axial load on the armed shoe it creates translatory-rotary movement downwards.

EFFECT: providing reliable and simple design with minimum loads on threaded connections of casing pipes, with reduction of time of drilling of shoe due to reduction of its length and reduction of quantity of parts, ingress of sludge and cement into the column is prevented.

1 cl, 2 dwg