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

FIELD: oil producing industry, applicable in development of oil formations by 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 Na₂CO₃ and aqueous solution of hydrochloric acid HCl, and pushing of over formation by displacing fluid. Prior to injection into formation of aqueous solution of soda ash, aqueous solution of aluminum chloride AlCl₃. is injected. Aqueous solutions of reagents may be injected with the following ratio of their volumes: AlCl₃: Na₂CO₃: HCl= (0.08-1.0):(1.0-2.5):1. Pushing may be effected after injection of each reagent. In a row of cases, operations of injection and pushing of aqueous solutions of soda ash and hydrochloric acid are repeated. EFFECT: increased oil recovery due to increased coverage of oil pool with waterflooding and withdrawal of difficulty recoverable reserves concentrated in formation roof part. 4 cl, 1 tbl, 1 ex