TOOL TO PUNCH HOLES IN CASING STRING Russian patent published in 2004 - IPC

FIELD: oil and gas industry, equipment utilized for lifting of cement from behind casing string during overhaul of well. SUBSTANCE: proposed tool includes cylindrical body, drive, cone, nut with shear annular grooves, nut making up screw pair with shaft, threading dies, pins. Drive comprises electric motor and reduction gear for shaft rotation. Nut with shear annular grooves is destroyed in case of emergency release of tool. Threading dies are mounted on cone for vertical and horizontal movement over surface of cone. Pins are placed on threading dies to punch holes in casing string. Pins can be removed from punched holes with supply of current of reversed polarity to electric motor. EFFECT: simplified design and eased attendance. 2 dwg