METHOD FOR TREATING BOTTOM-HOLE ZONE OF PRODUCTIVE OIL BED Russian patent published in 1998 - IPC

FIELD: oil production industry. SUBSTANCE: this relates to treating bottom-hole zone of productive bed made of dense low-permeable terrigenous rock through deep wells with recovering high-viscous oil. According to method, initially injected is 3-15% solution of sodium tripolyphosphate, then injected are following materials: hydrocarbon-alkaline solution containing 30-40% solution of alkali metal hydroxide - 11-15 mass%, butethal - 1.5-2.5 mass%, methanol - 1-2 mass%, hydrocarbon solvent - the balance. After that, injected is 0.5-1% solution of polyacrylamide. Prior to injection into bottom-hole zone, 3-15% solution of sodium tripolyphosphate is held in well under pressure during 16-32 h. After injection of 0.5-1% solution of polyacrylamide, pressure in well is increased and repressuring is created on productive bed equal in value to 0.5-2 MPa. Solutions of sodium tripolyphosphate, hydrocarbon-alkaline and polyacrylamide are injected in following amounts per 1 lin. m of perforated capacity of productive bed: 0.5-1, 1-5, 3-6 m3 respectively. Solution of polyacrylamide is pressure-forced into bottom-hole zone by means of brine water. Application of aforesaid method reduces corrosive activity of used solutions, increases injection depth and allows for lowering of injection pressure. EFFECT: higher efficiency. 4 cl