UNDERGROUND EQUIPMENT FOR OPERATION OF WELLS Russian patent published in 1997 - IPC

FIELD: oil and gas industry. SUBSTANCE: underground equipment has cylindrical bush 1 located in production string 4 and rigidly connected by its lower end with sleeve 2. Connected to lower part of sleeve 2 are casing 5 and bottom 7 with central axial passage 8 closed by ball-type shut-off member 9. Casing 5 and bottom 7 are connected by shear members 6. Located on top of bush 1 is housing 17 having axial washing passages 18 and central axial passage for accommodation of tubing 12. Made in housing 17 is internal groove and in bush 1 is external groove for accommodation of fixing member 19 in the form of split springy ring. Located inside housing 17 and bush 1 is piston 14 which can reciprocate inside them. Mounted above coupling 13 is housing 17, and below it is mounted piston 14 having additional axial passages for installing there inhibiting valve 16 and circulation valve 15. Height of internal part of housing 17 is larger than distance from lower end of piston 14 to upper end of coupling 13. Diameter of central axial passage in housing 17 is less than outer diameter of coupling 13 but it exceeds outer diameter of tube 12. Sleeve 2 is made of plastic material and covered with layer of sealing material 3. Cylindrical bush 1 with sleeve 2, casing 5 and bottom 9 is lowered by tube string into production string 4 to required depth. Excessive hydraulic pressure is created in sleeve 2. Sleeve 2 is deformed in radial direction and tightly pressed against walls of production string 4. Then shear members 6 are destroyed and bottom 7 with locking member 9 are lowered to bottom hole. Tube string is detached from cylindrical bush 1 and raised to well head where piston 14 is connected to them over which housing 17 is seated. Housing 17 with piston inside it is lowered into production string 4. Housing 17 is seated on cylindrical bush 1 and fixed on it by member 19. Piston 14 is brought into cylindrical bush 1. Upon that, well head connections are realized with subsequent performance of following operations: flushing, perforation-firing work, completion, commissioning, etc. EFFECT: high efficiency. 6 cl, 2 dwg