METHOD OF INTERVAL ACID TREATMENT OF BOTTOMHOLE ZONE, MAINLY, OF HORIZONTAL WELLS Russian patent published in 2003 - IPC

FIELD: oil production; applicable in intensification of oil producing from producing formations with nonuniform reservoir properties tapped by wells with horizontal directional and vertical bores, with use of acid treatment of low-permeability sections of bottomhole zone. SUBSTANCE: method includes injection into formation mainly of horizontal wells of plugging composition based on hydrocarbon emulsion and subsequent injection of acid with density of plugging composition or differing by not more than by 5%. Plugging composition based on hydrocarbon emulsion is used in form of composition containing hydrocarbon fluid, alkali emulsifier based on hydroxyethylated ethanols, or hydroxyethylated glycols, starch, alkali metal hydroxide, water-soluble alkali- metal borate and water mineralized with potassium and/or sodium chloride with the following amounts of ingredients, wt.%: hydrocarbon fluid 4.8-8.0; alkali emulsifier based on hydroxyethylated ethanols or hydroxyethylated glycols 0.12- 4.0; starch 2.5-4.5; alkali metal hydroxide 0.25-0.45; water-soluble alkali metal borate 1.2-3.5; the balance, water mineralized with potassium chloride and/or sodium chloride. Hydrocarbon fluid is used in form of oil, or transformer oil. Technical result of invention consists in increase of efficiency of acid treatment of low-permeability zones of formation by more reliable temporary blocking of high-permeability intervals of wellbore for period of conduction of acid treatment due to high viscoelastic properties of used plugging composition and prevented formation of oil-acid and water-oil emulsions in reaction of said plugging composition with formation fluids, with preserved process properties of plugging composition at temperature of up to plus 90C. EFFECT: higher efficiency of method.