DOWNHOLE INNER SPEAR Russian patent published in 2016 - IPC E21B31/20 

FIELD: oil industry.

SUBSTANCE: invention relates to oil industry and is intended for extraction from the well of oil-well tubing, casing and drill pipes, downhole equipment. Device includes a shaft with a through channel for flowing of the well fluid with an adapter in the upper part having an inner connection thread for screwing onto the drill pipe string. Spring-loaded spot unit in the lower part of the spear is brought into working position by a spring. Adapter at the bottom is equipped with a thread for release by screwing a thrust. Thrust at the bottom has teeth to be fixed onto extracted pipes or equipment. Spring is inserted in the thrust retaining the spots through the case in working position. Between the thrust and the case there is a ring inserted preventing the thrust flap during lowering into the well. Release mechanism is simplified to a common threaded joint between the adapter and the thrust. Coaxial arrangement of the spots minimizes crosswise loads bending the mandrel, thus maintaining serviceability of the spear after application.

EFFECT: higher efficiency, reliability and safety of extraction of pipes and equipment, simplified release mechanism.

1 cl, 1 dwg