METHOD OF DEVELOPMENT OF WATER-ENCROACHED OIL RESERVOIRS Russian patent published in 2003 - IPC

FIELD: oil producing industry. SUBSTANCE: method includes injection into formation of aqueous solution of acrylic polymer with biologically active substance and subsequent injection of displacement agent. Biologically active substance is used in form of carbohydrate and yeast with the following amounts of components, wt.%: carbohydrate 4.0-20.0; yeast 0.5-2.0; acrylic polymer 0.01-10.0; the balance, water. Prior to injection of displacement agent, oil is injected. It is possible to introduce into said mixture of nonionic surfactant in amount of 0.5- 1.0 wt.%. Volume ratio of said aqueous solution and oil amounts up to 10.0:1.0, respectively. EFFECT: increased oil recovery from water-encroached formations. 3 cl, 1 tbl