DEVICE FOR EFFECTIVE ISOLATION OF PRODUCTIVE BED AT CEMENTATION OF OPERATING TUBES Russian patent published in 1997 - IPC

FIELD: equipment for completion of oil and gas wells. SUBSTANCE: device ensures reduction of rigidity, retention of cross-sectional area of casing string, improvement of plugging reliability. Device has external tube into which internal tube is inserted with eccentric clearance. Isolating components are placed at ends of tubes. Isolating components are opened by means of drive which is made in the form of hydraulic cylinders with annular pistons and wedges. Internal tube is made of easily drilled material. Isolating components are made in the form of rubber bushes which are located between annular pistons and wedges. Wedges are installed for possible interaction with rings of preliminary closing. At opposite ends they are made with additional tapered surfaces interacting with rubber bushes. EFFECT: high efficiency. 3 cl, 5 dwg