METHOD OF ACID TREATMENT OF BOTTOM-HOLE FORMATION ZONE Russian patent published in 1997 - IPC

FIELD: oil and gas producing industry. SUBSTANCE: method of acid treatment of bottom-hole formation zone of producing formations with absent or low their intake capacity includes injection of acid solution through the tubing string, lowered to the level of the upper holes of the perforated interval. For this purpose, prior to supply into tubing string of initial portion of acid solution, weighting agent is introduced into acid solution in form of heavy salt of inorganic acid, mainly, calcium chloride or zinc chloride to obtain solution density exceeding the density of well fluid present within the perforation interval, and solution volume corresponding to the volume of bottom-hole volume in the interval of perforation. Supply of portion of solution obtained as specified above into well to fill the perforation interval is carried out with open annulus gate valve. EFFECT: provision of replacement of well fluid present in perforation interval with injected solution and contact of acid with rock of bottom-hole formation zone. 2 cl, 1 tbl