METHOD AND DEVICE FOR PRODUCTION STRING SEALING DURING SANDY WELL FLUSHING Russian patent published in 2007 - IPC E21B37/00 E21B33/13 E21B33/122 

FIELD: oil production, particularly methods or devices for cementing, for plugging holes, crevices, or the like.

SUBSTANCE: method involves simultaneously installing two packing mechanisms connected with each other through pipe; flushing well so that counter-current flushing flows passing through tubing string and annular space are directed through isolated channels made in packing mechanisms and in packing mechanism connection pipe, wherein the first isolated channel connects inner tubing string areas located upstream and downstream of packing mechanisms and the second one communicates inner annular space areas upstream and downstream of packing mechanisms. Device comprises packing mechanism including bottom-hole packer, which seals tube space due to packer diameter increase as a result of axial compression thereof, the first pipe located inside bottom-hole packer and tube with radial orifices. Bottom-hole packer end is fastened to the first pipe so that packer may be displaced in vertical direction by to packer deformation. Device comprises two packing mechanisms. Upper mechanism includes inner pipe inserted in outer pipe and having sealing means to provide air-tight sliding thereof inside tubing string. Sealing means have diameters exceeding that of inner pipe. Pipe with radial orifices has upper end threadedly connected with tubing string and is provided with inner bead. Inner bead diameter is less than that of sealing means made in inner pipe. Lower end of pipe with radial orifices abuts against upper bottom-hole packer end. Bottom-hole packer is fastened to outer pipe by lower end thereof. Lower packing mechanism is identical to upper one. Lower packing mechanism is coaxially arranged upside down below upper packing mechanism. Upper and lower packing mechanisms have common outer and inner pipes. Pipe with radial orifices of lower packing mechanism is threadedly connected to stem including lower sealing means of inner pipe installed in stem interior.

EFFECT: increased quality and decreased production string sealing time.

2 cl, 2 dwg