METHOD FOR HYDROMECHANICAL SLIT PERFORATION OF CASED WELLS AND DEVICE FOR REALIZATION OF SAID METHOD Russian patent published in 2005 - IPC

FIELD: oil and gas extractive industry.

SUBSTANCE: method includes lowering perforator on tubing string into well to perforation range. Well shaft is washed. Longitudinal slit is formed in walls of casing column by reciprocal movements of tubing string. Cement ring and rock around formed slit are cleaned out by hydromonitoring jet. Load on casing column is kept under constant control by changing pressure at output of pump. Longitudinal slit in walls is formed during step-by-step increase of pressure on tubing string and concurrent control of forces of drawing-ups and fits. Increase of pressure on tubing string is performed until longitudinal slit is cut and drawing-ups and fits disappear. Following washing of cement ring and rock around formed slit is performed concurrently. Device includes sliding support, body with two spring-loaded pistons in it. The latter are interconnected via hollow rod, having apertures for liquid circulation, shear circulation valve mounted in upper portion of body, channels for passing pf washing liquid. One of said channels ends with hydromonitoring head piece, placed on pusher piston of cutting assembly, consisting of extending knurling roller connected by fork to pusher piston. Springs of pistons are welded in place of their contact with pistons. Compacting elements of the latter have edges slanted at 33-35°. Fork, in its lower portion, on the side of touching with inner surface of perforator body near output of knurling roller, is made with cut at angle of 10-15° relatively to longitudinal axis of perforator. Sliding support is mounted with space relatively to pusher piston. Second channel for passing of washing liquid ends by branch pipe. Sliding support in lower portion of perforator body is fixed by screw and nut. Washing channel with hydromonitoring headpiece in lower portion has rounded walls and its diameter is greater than diameter of output aperture.

EFFECT: higher productiveness.

2 cl, 1 dwg, 1 ex