UNDERGROUND EQUIPMENT FOR OPERATING WELLS Russian patent published in 1997 - IPC

FIELD: oil and gas industry. SUBSTANCE: underground equipment has pipe union 1 connected with lower coupling 2 of pump-and-compressor tube string 3. Lower end of pipe union 1 is connected with holder 5. Located concentrically outside pipe union 1 is sleeve 11. Upper end of sleeve 11 by means of left-hand thread is connected with body 13, and seated in its central axial passage is pipe union 1. It can reciprocally move in axial direction relative to body 13. Two circular bores are made in body 13. One bore accommodates sealing collars 21, spacer ring 19, thrust rings 18, pressure piston 20 and axle box 22. Seated in other bore is safety piston 28. Also made in body 13 are internal circular protrusion 16, stepped axial passages 14, through axial passages 15, and splines 17. Axes of stepped passages 14 are located at larger distance from axis of central passage of body 13 than axes of through passages 15. Installed in stepped passages 14 are circulation valve 24 and inhibiting valve 23. Made in upper part of holder 5 are radial passage 10 and splines 9 which are counterpart to splines 17 of body 13. Attached to lower end of sleeve 11 is cover 12 which is installed on holder 5 with possible reciprocal displacement relative to it. Sleeve 11 itself is made of flexible material. In transport position, sleeve 11 is deformed in radial direction over its length. Outer surface of sleeve 11 can be coated with layer of sealing material. Attached to holder 5 underneath is bottom 6 with axial passage 7 which is closed by shut-off member 8. Underground equipment is sunken into well to required depth by string of pump-and-compressor tubes 3. Surplus pressure is created in sleeve 11, it is deformed in radial direction and tightly pressed against walls of production string 4. At further increase of pressure inside sleeve 11, bottom 6 is detached from holder 5. Required connections are made at well head, and surplus pressure is created in hole clearance. Protective piston 28 goes out of circular bore of body 13, thus freeing stepped passages 14. After that, underground equipment is ready for carrying out further technological operations. EFFECT: high efficiency. 5 cl, 1 dwg