DEVICE FOR STEPPED CEMENTATION OF WELL Russian patent published in 1997 - IPC

FIELD: oil and gas industry. SUBSTANCE: this relates to cementation of oil and gas wells with close location of oil and gas bearing horizons. Device is highly reliable at high loads on lower extendable stops at second stage of cementation. Device has composite body with central through passage, radial holes, and inner surface with annular protrusions and recesses. Installed in body are two-position bush with holes and limiter of bush first position. Limiter is in the form of ring and it has member for catching with bush at its stroke, and extendable stops taken out of passage. They are located in side tapered holes (separators) in ring and bush respectively. Stops interact with inner surface of body. Bush is fixed by screw. Ring catching member is of shear type. Recess of body inner surface 17 is double-stepped and narrowing from top to bottom. Outer surface of ring in zone of upper step of aforesaid recess also has double-step recess and it is widening from top to bottom. Seated in its lower step is annular stop. Bush has additional holes in zone of annular stop which accommodate annular locks of bush 9. Extendable stops are connected with spring-type deflectors. EFFECT: high efficiency. 1 cl, 4 dwg