BOREHOLE TOOL TO EXTEND CASING AND METHOD FOR CASING EXTENSION WITH ITS USE Russian patent published in 2017 - IPC E21B43/10 E21B29/10 

FIELD: mining engineering.

SUBSTANCE: group of inventions refers to tools for drilling and completion of wells. The tool contains an extension module and a drive module for driving the expansion module and performing the expansion. The drive module comprises a central pipe, an intermediate pipe and an outer pipe which are arranged in series in direction from the center to the periphery of the module. The downstream end portion of the central pipe is connected to the drill pipe and can be closed. The central tube has a hole for the passage of liquid. The intermediate pipe rigidly connected to the drill string comprises a group of upstream and downstream sections that are rigidly connected to each other by the first connecting element. The downstream section of the intermediate pipe has a fluid inlet. The intermediate pipe is slidably connected to the central pipe by a stopper. The outer pipe connected to the intermediate pipe by means of the fourth shear pin comprises a group of upstream and downstream sections rigidly connected to each other by a second connecting element. The first and second connecting elements are arranged downstream respectively above and below said fluid inlet and come into contact slidably and form a seal along with the outer pipe and the intermediate pipe, so that the first connecting element, the second connecting element, the downstream section of the intermediate pipe and the upstream section of the outer pipe form together a hydraulic chamber. The module comprises a plurality of extension petals mounted movably on the downstream end portion of the downstream outer pipe section, and a cone support rigidly fixed and downstream than the extension cone petals.

EFFECT: constant borehole diameter and internal casing diameter of the casing, which provides drilling of deeper holes.

22 cl, 15 dwg