METHOD OF DEVELOPING WATER-FLOODED OIL POOL Russian patent published in 2002 - IPC

FIELD: oil producing industry; applicable in regulation of development of oil deposits, equalization of injectivity profile of injection wells and restriction of inflow of formation water in oil wells. SUBSTANCE: method includes withdrawal of fluid from producing well and periodic injection of sediment-forming reagent of alkaline type into injection wells. Solution of said reagent is injected in two stages. Injected first is a solution with reagent concentration of 0.1-5 wt.% and then, a solution with reagent concentration of 5-25 wt.% is injected. Then, additionally injected is a solution of calcium chloride. Sediment-forming reagent is used in the form of sodium phosphate. Ratio of sodium-phosphate injected at the second stage to calcium chloride is 1:(0.7-1.3). EFFECT: higher efficiency of oil pool development due to increased coefficient of oil displacement, redistribution of filtration flows and development of dead and slightly drained zones. 2 ex