FACILITY FOR STAGE CEMENTING OF CASING STRING Russian patent published in 2004 - IPC

FIELD: oil and gas production, two-stage cementing of casing strings in oil and gas wells. SUBSTANCE: facility has body with rest and circulation holes, door placed inside body above circulation holes and joined to it with the aid of shear elements, location bushing installed inside door and linked to it by means of pins, fixing arm located between body and door and driving plug comprising rod and elastic member. Door and rest have opposing grooves and protrusions. In compliance with invention facility is fitted with housing placed over perimeter of body to form common space opposite to circulation holes. Gate connected to body with the use of shear elements is installed in mentioned space above holes. Inner diameter of location bushing accommodates outer diameter of lower part of driving plug in which conical bore additional fixing arm is placed. EFFECT: facility demonstrates high operational reliability, success and high quality of operations of injection of cement slurry of second stage. 3 cl, 1 dwg