METHOD OF TREATING WELL BOTTOM-HOLE ZONE Russian patent published in 2001 - IPC

FIELD: oil-producing industry. SUBSTANCE: method consists in that before injection of working solution, well is washed with washing solution of service water and 3% solution of potassium chloride; tubing pipes are gradually lowered to upper perforation zone; further washing down to bottom-hole is effected with 2% solution of carboxymethyl cellulose on 3% solution of potassium chloride with addition of 0.1% of surfactant. Tubing lower end - shoe is installed at level of strainer middle part. Then solution of 12% technical hydrochloric acid is injected with addition from 0.8 to 1.2% of surfactant under conditions of rinsing by alternating injection into tubing pipes and annular space (dynamic acid bath) for up to 2 h. After washing, formation is subjected to treatment with working solution of 12% hydrochloric acid with addition of 0.8-1.2% of surfactant in amount of 0.5-0.7 cu.m/m of opened effective thickness of formation with subsequent allowing to stand up to 3 h, cleaning of bottom-hole from reaction products by their washing or forcing into formation by volume of low-concentrated hydrochloric acid exceeding the volume of working solution by a factor of 2-3 with addition of nonionic surfactant with high adsorption capacity. EFFECT: higher efficiency of formation treatment, increased formation productivity at temperature of about 60 C.