METHOD OF BOREHOLE PERFORATION Russian patent published in 2013 - IPC E21B43/11 

FIELD: oil and gas industry.

SUBSTANCE: at borehole perforation after descending into the borehole the perforator is fixed to prevent turning and shifting. Perforation is made in fixed condition. After perforation is complete the perforator is lifted from the borehole, charged and descended into the borehole again. At borehole perforation after the perforator is again descended into borehole it is fixed in position shifted by azimuth and/or vertically in relation to position it was in at first descending. Repeated perforation is made in fixed condition, after repeated perforation the perforator is lifted from borehole, if necessary the perforation is repeated again.

EFFECT: invention provides combining the place of cumulative perforation action at the second and the following perforation cycles with the place of perforation action at the first perforation cycle, changing the form, extending and deepening perforation holes in the borehole, reducing the negative effect on annulus cement stone at reaching borehole connection with annulus area.

3 cl, 4 dwg, 5 ex