INJECTIVITY PROFILE CONTROL METHOD FOR INJECTION WELL AND WATER INFLUX RESTRICTION METHOD FOR PRODUCING WELL Russian patent published in 2006 - IPC E21B33/138 C09K8/90 

FIELD: oil field development, particularly to produce oil from deposit having reservoirs with non-uniform permeability to control injectivity profile in injection well and to restrict water influx in producing well.

SUBSTANCE: injectivity profile control method involves injecting polysaccharide-based gelling composition, polyvalent metal composition and water in injection well; performing time delay to provide gel formation, wherein the polysaccharide is xanthane generated by Xanthomonas campestris microorganisms, the polyvalent metal composition is chromium acetate and/or chromic potassium alum added to water having mineral content of 0.5-100 g/l taken with ratio of 1:1. Surfactant, namely hydroxyethylated alkyl phenol is added to the composition. Above substances are taken in the following amounts (% by weight): xanthane - 0.05-0.3, chromium acetate and/or chromic potassium alum - 0.005-0.2, hydroxyethylated alkyl phenol 0.5-1, remainder is water. The time delay is performed for 3-10 days. Water influx restriction method involves injecting polysaccharide-based gelling composition, polyvalent metal composition and water in producing well; performing time delay to provide gel formation, wherein the polysaccharide is xanthane generated by Xanthomonas campestris microorganisms, the polyvalent metal composition is chromium acetate and/or chromic potassium alum added to water having mineral content of 0.5-100 g/l taken with ratio of 1:1. Above substances are taken in the following amounts (% by weight): xanthane - 0.05-0.3, chromium acetate and/or chromic potassium alum - 0.005-0.2, remainder is water. The time delay is performed for 3-10 days. In the case of gelling composition injection in producing well having high injectivity filler taken in amount of 0.025-3 % by weight may be added to the composition.

EFFECT: increased oil recovery from reservoir and decreased water influx due to improved filtration resistance of flushed zones due to creation of residual flow resistance factor with the use of gelling compositions, extended technological capabilities of the method and reduced power inputs.

3 cl, 2 tbl