DEVICE FOR SHUTOFF OF WELLBORE Russian patent published in 1995 - IPC

FIELD: oil producing industry. SUBSTANCE: device for shutoff of wellbore includes hollow body 1 with radial channels. Cylindrical sleeve 8 is concentrically installed in body 1 for closing radial channels. Located on body is flexible sealing member 6 which forms hollow together with body. Uniformly located in hollow are mechanisms extending sealing member made in form of piston pusher 5 rigidly connected with sealing member and two immovable concentric cylinders 3 and 4. Cylinders form two chambers - cylindrical washing and circular working ones. Pistons of pusher 5 are accommodated in chambers. Body at the level of washing chamber has radial holes in respective pusher pistons and movable sleeve. Working chamber is communicated with body hollow by means of radial channels. Check valve is installed in upper part of body and two springs different in length are located in lower part. Rigidity of long spring is less than that of short spring. When pressure is built up in body 1, sleeve 8 moves downward. This results in washing of wall of shutoff well through washing chamber, and then, pressure rises in working chamber, and extending mechanism operates and sealing members shutoff the wellbore. EFFECT: higher efficiency. 2 cl, 2 dwg