METHOD FOR WATER INFLOW ISOLATION IN HIGH-TEMPERATURE RESERVOIRS Russian patent published in 2006 - IPC E21B33/138 

FIELD: oil and gas industry, particularly for water inflow isolation and for remedial cementing of production and injection wells in high-temperature reservoirs.

SUBSTANCE: method involves injecting acrylamide polymer composition in well. The composition includes aqueous solution of cross-linking agent and acrylamide polymer having molecular mass of not more than 1 million and degree of hydrolysis of not more than 0.5% so that hydrolysis is carried out at 70°C reservoir temperature to form strong gel in cross-linking agent presence. The acrylamide polymer is nonionic acrylamide polymer. The cross-linking agent is chromium acetate or urotropin with hydroquinone. The composition may additionally have gelling control agent, for instance weak organic acid, namely sulphosalicylic acid. Composition may comprise 1-7% by weight of acrylamide polymer, 0.1-0.5 % by weight of cross-linking agent, 0-1.0% by weight of gelling control agent and water as remainder. Optimal composition formulation is chosen with taking into consideration of gelling kinetics and filtering composition properties obtained as a result of laboratory research.

EFFECT: increased efficiency due to increased isolation quality, increased injection depth and strength of structured isolation composition formed in watered area, extended temperature range of polymeric composition usage.

6 cl, 1 ex, 1 tbl, 2 dwg