WELL BOTTOM ZONE TREATMENT METHOD Russian patent published in 2007 - IPC E21B43/27 E21B33/13 E21B37/00 

FIELD: oil production industry, particularly secondary completion for producing formation interval treatment for the purpose of crevice accumulation in annular space of producing wells.

SUBSTANCE: method for well bottom zone treatment by supplying acid adapted to act on formation rock via hydraulic monitor nozzles involves isolating producing formation interval from grouting mortar ingress due to usage in casing pipe assembly including modular formation isolation means, wherein the formation isolation means comprises hydraulic monitor nozzles with magnesium caps in lower part of formation isolation means and magnesium caps in upper part thereof; cementing annulus; lowering packer connected to tubing string in central part of modular formation isolation means; injecting hydrochloric acid; executing time delay for magnesium cap opening; isolating upper part of modular formation isolation means from lower part thereof by packer seating; creating increased pressure in lower part of modular formation isolation means through pipe string; creating crevices in producing formation by acid jets supplied through hydraulic monitor nozzles and washing-out producing formation decomposition products into casing pipe.

EFFECT: improved efficiency of crevice volume increase in producing formation, contamination breaking and removal during first completion of reservoir layer and, as a result, enhanced oil recovery.