METHOD OF SHUTOFF OF WATER INFLOW TO WELL Russian patent published in 2002 - IPC

FIELD: oil and gas producing industry, particularly, methods of shutoff of water inflows to oil and gas wells, elimination of annular spaced crossflows and lost circulation in well drilling, alignment of flood front in injection wells. SUBSTANCE: method includes injection of suspension of water-soluble polymer in organic fluid into well bottom-hole formation zone, forcing of said suspension into formation by water, and allowing it to stand for definite time. Suspension concentration amounts up tp 21-50%. Polymer is used in the form of polyacrylamide and/or its derivatives, polyvinyl alcohol and/or its derivatives, carboxymethyl cellulose and/or its derivatives. High pressure is built up and dwelling is effected under said pressure. Injected into well is 0.5-4.0 cu.m of suspension of water-soluble polymer in organic fluid per each running meter of formation effective thickness. Organic fluid is used in the form of pure oil, distillate, kerosene, gas oil, hexane, gasoline, condensate, diesel fuel. Pressure under which suspension of water-soluble polymer in organic fluid is injected amounts at wellhead up to 1.0-40.0 MPa. Displacing fluid is used in the form of water with pH 4-12. Dwelling under pressure is continued for 3-72 h. EFFECT: improved water-shutoff properties of water-soluble polymers in elimination of water inrushes to producing wells and annular space crossflows and limited injectivity of injection wells within wide range of temperatures. 6 cl, 3 tbl