METHOD FOR SHUTOFF OF INFLOW OF FOREIGN WATER FROM CASING STRING-BORE-HOLE ANNULUS Russian patent published in 1994 - IPC

FIELD: shutoff of foreign water in wells. SUBSTANCE: method consists in running of tubing into flow string down to zone of shutoff. Isolating material is supplied through tubing and injected at pressure to casing string-borehole annulus. Injection is carried out at definite rate that ensures injection pressure at the level of shutoff zone. Pressure value of expected maximum depression in process of development or operation of well not less than by 3 MPa. Then, well is kept under pressure to let cement set. Pressure value during well keeping at pressure is maintained at level not less than difference between formation pressure and pressure in flow string. Time for keeping well under pressure is not less than time of beginning of setting of isolating material. In this case, this time is not higher than 2/3 of time of isolating material setting. EFFECT: higher quality of shutoff. 1 dwg