METHOD OF SECONDARY TAPPING OF OIL AND GAS WELL PRODUCING FORMATIONS Russian patent published in 2003 - IPC

FIELD: drilling and repair of producing wells, particularly, secondary tapping of producing formations. SUBSTANCE: method includes perforating of cased main wellbore by cutting out of windows in casing string and tapping of producing formation in its bottomhole zone by drilling through windows of radial perforation channels with bypassing the boundaries of levels of gas-water, gas- oil, water-oil interproduct contacts. Said radial perforation channels are drilled with departure from main wellbore ensuring tapping of all producing interlayers of formation and subsequent stimulation of formation product inflow to well. Before drilling of radial channels from main wellbore, injected to bottomhole zone through perforations holes in casing string is isolating-binding gel-forming or cement slurry to depth less than distance of departure of these channels from main wellbore but larger than existing or prognosticated depth of spreading of boundaries of levels of interproduct contacts. Formed in drilling of radial perforation channels are curved wellbores including descending and ascending and ascending branches. EFFECT: higher efficiency. 2 cl, 2 dwg, 1 ex