METHOD FOR RECOVERY OF RESIDUAL OIL Russian patent published in 1998 - IPC

FIELD: oil production industry. SUBSTANCE: this relates to method of recovering residual oil at late stage of deposit exploitation. According to method, injected into oil bed is washing-off solution containing alkali and surface-active material. Prior to injection of solution, water-permeable sections of oil bed are subjected to isolation by injection of disperse system which is suspension of wood flour which swells in alkali medium but is not dissolved in alkali medium. Used as washing-off solution is washing detergent means. Application of aforesaid method increases oil recovery from beds and reduces flooding of product being extracted. EFFECT: higher efficiency. 3 cl, 5 tbl