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

FIELD: oil producing industry; applicable in development of oil pools with help of waterflooding. SUBSTANCE: method includes displacement of oil by gas-fluid fringe formed by successive injection into formation through injection wells of aqueous solution of soda ash and aqueous solution of hydrochloric acid, and pushing it over formation by displacing fluid. Prior to injection of aqueous solution of soda ash into formation, aqueous suspension based on polyacrylamide and aqueous solution of aluminum chloride are successively injected. Added to aqueous suspension based on polyacrylamide may be sodium bichromate. Pushing may be effected after injection of each reagent. In a number of cases, operations of injection and pushing of soda ash and hydrochloric acid aqueous solutions are repeated. EFFECT: increased oil recovery due to increased coverage of pool with waterflooding and withdrawal of difficulty recoverable reserves concentrated in roof part of formation. 4 cl, 1 tbl, 1 ex