SHOE FOR CASING STRING Russian patent published in 2020 - IPC E21B17/14 

FIELD: mining.

SUBSTANCE: invention relates to mining industry and can be used for lowering of casing string to borehole in process of its construction for passage of benches and cavernous sections. Shoe for casing string includes hollow cylindrical body with connecting thread in upper part. In the lower part of the hollow cylindrical body there are guiding grooves and recesses with possibility of installation of working springs. Hollow cylindrical housing is equipped with three moving guide dies with through holes at an angle to axis of hollow cylindrical housing. Moving guide dies are arranged in circumferential direction of housing 120 °C and have internal process blind holes, in which the lower parts of working springs are borne. In place of closure of guide grooves there rigidly installed is end cylindrical plug with through central hole of fungoid type with protrusions on lower part, allowing to hold movable guide dies in housing.

EFFECT: higher reliability of lowering and installation of casing string in complicated borehole, higher impact strength and wear resistance of shoe.

1 cl, 5 dwg