METHOD FOR TREATMENT OF BOTTOM-HOLE FORMATION ZONE AND DEVICE FOR ITS REALIZATION Russian patent published in 1995 - IPC

FIELD: oil production. SUBSTANCE: device has packer with sealing member and branch pipe with ports. Upper part of packer has seat for valve installed on tubing string. Packer lower part has retainer. Mechanism for producing depression-repression action consists of two-stage cylinder 7 with cone recesses and window rows located one above the other. Installed inside cylinder 7 are three pistons 10-12. Pistons 10 and 11 have radial holes 13 and 14, respectively, and bushing 15 is fitted in cylinder 7. Middle piston 11 is simultaneously connected with the second concentrically installed bushing 21 with piston 12 fitted on bushing upper end. Located in lower part of bushing 15 is chip catcher 19 accommodating check valve 20. Tubing string is alternately lifted and lowered to height corresponding to distance between extreme parts in rows A and B. In this case, packer remains in packed position. Successive coincidence of holes 13 of piston 10 with ports A₁, A₂, A₃. .. of cylinder 7, underpacker zone is promptly communicated with pipe hollow. This results in multiple pulses of deep and sharp depression on formation in form of direct hydraulic impacts directed from formation to well. During successive coincidence of holes 14 of piston 11 with ports A₁, A₂, A₃..., abovepacker tubing-borehole annulus is communicated with underpacker space that leads to prompt rise of pressure under packer up to hydrostatic value and producing multiple pulses of sharp depression in form of reverse hydraulic impacts directed from well to formation. EFFECT: higher efficiency and operate reliability of packer. 2 cl, 2 dwg