METHOD OF OIL RECOVERY INCREASE FROM FORMATION Russian patent published in 2001 - IPC

FIELD: oil producing industry, particularly, methods of reduction of produced water and increase of oil recovery from formations at late stage of development with high water cutting of produced fluid (above 70%). SUBSTANCE: method involves successive injection into producing well of aqueous solution of salt of multivalent metal and aqueous solution containing cations of metals with their subsequent forcing into formation. Aqueous solution containing cations of metals is used in the form of waste produced water. In this case, injected after waste water is cation-active surfactant. EFFECT: reduced volume of produced water and higher oil recovery due to reduced permeability of water-encroached partings and formation sections and involving into development of low-permeable oil-saturated intervals of formations. 2 tbl