DETACHING TOOL Russian patent published in 2020 - IPC E21B33/127 E21B43/12 

FIELD: drilling of wells.

SUBSTANCE: proposed invention relates to well system. Well system comprises an upper casing pipe and a lower casing located in the borehole and containing one or more annular barriers having an expanding sleeve. Lower casing pipe is attached to the upper casing pipe by means of an annular barrier. Borehole system according to this invention additionally comprises detaching tool, intended for disconnection of drill pipe from lower casing pipe in well bore. Disconnecting tool comprises an outer surface, an axial force generator comprising a first portion and a second portion and axially moving the second portion relative to the first portion along the axial length, a cable feeding the axial force generator, and element comprising drive part and tail part. Tail part is connected to second part, wherein from leading part to tail part fluid channel passes, intended for passage of fluid medium or passage of fluid medium through element at movement of second part relative to first part of axial force generator during disconnection. Fluid channel has an inlet hole in the drive edge and an outlet hole terminating on the outer surface of the tool.

EFFECT: technical result is improvement of solution for detaching running tool and drill pipe from lower casing without damaging zone insulation provided by uncovered annular barriers.

14 cl, 20 dwg