METHOD OF WELL REAGENT TREATMENT Russian patent published in 2001 - IPC

FIELD: oil and gas producing industry, particularly, methods of reagent treatment of wells for increase of production rate of producing formations, removal of colmatage formations and action on permeability of rocks composing producing formations. SUBSTANCE: method involves successive injection into formation of process solutions with acid, alkali reaction of media reacting with colmatage formations of natural and/or technogenic genesis in well perforated zone and separated by buffer fluid containing solution of surfactant, leaving to stand of process solution in formation for reaction, and subsequent removal of process solution, buffer fluid and reaction products from formation. Successively injected into formation are the first process solution with acid reaction of medium in volume equalling volume of pore space on colmatage zone, buffer fluid in volume equalling ratio between the first process solution with acid reaction of medium and volume of buffer fluid within 1:(3-3.5); the second process solution with alkali reaction of medium in volume equalling volume of pore space of colmatage zone, the second buffer fluid in volume equalling ratio between volumes of the second process solution with alkali reaction of medium and volume of buffer fluid within 1:(1-1.5); the third process solution with acid reaction of medium in volume equalling volume of pore space of colmatage zone. Time of leaving to stand of process solution in formation is set depending on formation temperature: for the first and third solutions with medium acid reaction at temperature of 120-140 C, 1-2 h; at temperature of 90-120 C, 2-4 h; at temperature of 50-90 C, 406 h; for the second process solution with alkali reaction medium at temperature of 120-140 C, 0.5-1 h; at temperature of 90-120 C, 1-1.5 h; at temperature of 50-90 C, 1.5-2.5 h. The first and second buffer solutions after injection into formation are not subject to leaving to stand. EFFECT: considerable increase of well productivity due to the fullest removal of clay colmatage particles from treated perforated well zone. 6 tbl