METHOD OF DEVELOPING OIL POOL Russian patent published in 1998 - IPC

FIELD: oil-producing industry, in particular, methods of oil recovery by means of displacement water. SUBSTANCE: method includes injection of air, water and surfactant through injection wells and withdrawal of oil through producing wells. Oil is displaced by single-phase air-water solution in pretransient phase state. Air and water are mixed at formation pressure and ratio from 0.27:1 to 0.36:1. In the course of injection of water-air solution into formation, bottom-hole pressure-to-formation pressure ratio is maintained within 1.1-1.8. Surfactant is added to water prior to its mixing with air. Surfactant is used in the form of 0.01-0.1-% cationic surfactant. EFFECT: higher oil recovery formation due to increased sweep of formation by displacement, and reduced corrosion of oil field equipment. 1 tbl