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

FIELD: well drilling and servicing, particularly, secondary tapping of producing formations. SUBSTANCE: method includes provision in producing formation and higher of its uncased section of main wellbore, with slime washing with drilling mud, of secondary tapping by drilling in bottomhole formation zone, with use of tool assembly with deflecting tool, of radially directed perforation channels with curved side wellbores spirally converging in radial direction and consisting of descending sections passing into horizontal and/or horizontal-ascending sections with inlets in uncased section of main wellbore and outlets ensuring tapping of all interlayers of producing formation, and subsequent induction of formation fluid inflow to main wellbore. In so doing, after provision of uncased section of main wellbore, it is reamed, and plug is formed in it by filling with hardening composition. After hardening of said composition, formed in its plug is auxiliary wellbore coaxial to main wellbore with diameter and depth sufficient for drilling of perforation channels which are drilled with inlets located in uncased section over helical line by interval by interval axial displacement and turning of tool assembly with deflecting tool in auxiliary wellbore. EFFECT: increased overhaul period of well, its production rate, reduced pressure differential between formation and bottomhole pressure by increase of filtration zone of bottomhole formation zone, reduced permeability and increased stability of wellbore section of bottomhole formation zone. 3 cl, 5 dwg