METHOD OF OIL POOL DEVELOPMENT Russian patent published in 2003 - IPC

FIELD: oil producing industry; applicable in development of oil formations by flooding. SUBSTANCE: method includes injection of aqueous solution of sodium sulfate, pushing of aqueous solution over formation by displacement fluid and subsequent injection of aqueous solution of chlorine-containing reagent. Added to both solutions is 0.01-1.0 wt.% of carboxymethyl cellulose. Aqueous solution of sodium sulfate contains 1-30 wt.% of sodium sulfate. Chlorine-containing reagent is used in the form of calcium chloride or hydrochloric acid. Aqueous solution of calcium chloride contains 1-30 wt.% of calcium chloride. Aqueous solution of hydrochloric acid contains 1-30 wt. % of hydrochloric acid. Added to both aqueous solutions is up to 1 wt.% of detergent. Reagents injection and pushing of reagents by displacement fluid are repeated. EFFECT: higher oil recovery of formation due to increased amount and density of insoluble sediments. 7 cl, 1 tbl, 2 ex