METHOD OF OIL PRODUCTION Russian patent published in 2003 - IPC

FIELD: methods of oil production by waterflooding with use of large-exchange injections into producing formation of aqueous emulsion-suspension system. SUBSTANCE: method of oil production from reservoirs nonuniform in permeability with maintenance of formation pressure by waterflooding includes injection into formation through injecting well of composition including noionic surfactant spontaneously forming emulsion-suspension system in metered value into water. Method is distinguished by the fact that injected into formation is composition-reagent for oil production containing nonionic surfactant possessing demulsifying properties with respect to water-in-oil emulsion and additional aromatic hydrocarbon solvent with the following ratio of components, mas.%: aromatic hydrocarbon solvent, 50-75; nonionic surfactant, 25-50. Reagent is injected into formation periodically into injection well bottom-hole zone, and/or continuously metered into water line through which oil field waste water from oil treatment plant is injected into injection well. Said results in spontaneous formation in fresh or mineralized water of emulsion-suspension system from deposits of asphalteno-resinous-paraffin and flocculent agglomerates of solid phase and asphalt-resinous and paraffin components of oil. Required amount of reagent for periodic injection is determined depending on geometric sizes of bottom-hole zone of injection well and thickness of treated formation. Amount of reagent (Q², kg/day) for its constant dosing to water line of oil field waste water injected into injection well is calculated by formula. EFFECT: increased oil recovery and coverage of formation by waterflooding, higher oil production rate with simultaneous reduction of water cutting of well production. 4 cl, 1 tbl