METHOD OF TREATMENT OF BOTTOM-HOLE ZONE WITH CHEMICAL REAGENT Russian patent published in 2002 - IPC

FIELD: restoration of filtering characteristics of producing formation in bottom-hole zones of injection and producing wells. SUBSTANCE: method includes successive pumping into well of hydrocarbon suspension containing the following amounts of components, wt.%: sodium, or potassium, or calcium nitrite 25-30; carbamide 25-30; the balance, diesel fuel or kerosene; then, acid surfactant composition containing hydrochloric acid 5.0-23.0; hydrofluoric acid 2.0-10.0; ASPO solvent 5.0-25.0; nonionic surfactant 1.0-5.0; oxyethylene diphosphonic acid 1.0-15.0; the balance, water. After pumping of reagents, well is shut-in, and allowed to stand for process of reaction. Time required for reaction is controlled by value and rate of growing of pressure at wellhead; it is considered sufficient when pressure in well after attaining maximum value starts reducing. EFFECT: increased oil production rate and reduced water cutting of well production. 2 cl, 3 tbl