DRILLING COMPLEX OF FORMATION PROTECTION Russian patent published in 2018 - IPC E21B34/12 E21B43/12 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to devices for operating oil and gas wells. In the complex, two spherical locking bodies are used, working surfaces of which are protected by bellows-protectors, filled with oil under excessive pressure. Switching operations of upper valve are carried out by flexible remote control elements connected to ball of locking body and springs under action of pusher from surface. Second lower valve functions as emergency valve. Emergency valve has variable-pass passage and is triggered when well output exceeds design flow rate due to differential pressure between cross-sections of passageway. In shut-off organ there are preloaded springs that tend to close it. Locking body ball is closed to body by bolt connected to piston located in cylinder on which differential pressure acts. When differential pressure is exceeded, piston is shifted towards lower pressure, and bolt releases locking body ball, and springs move it to "CLOSED" position. Presence of oil in internal cavities of locking body ensures its long working capacity, and emergency valve – trouble-free operation of well.

EFFECT: invention can be applied to hermetical closing of wellbore during repair work.

1 cl, 2 dwg