OIL RESERVOIR DEVELOPMENT METHOD Russian patent published in 2022 - IPC E21B43/22 

FIELD: oil industry.

SUBSTANCE: proposal relates to the oil industry, in particular to methods for increasing oil recovery from porous or fractured-porous carbonate reservoirs. Method of oil formation development includes pumping into formation through an injection well of a surfactant composition, water and alkaline reagent and oil extraction through production well. Water mineralization is preliminarily determined. At mineralization of up to 0.15 g/l, a composition containing a surfactant with concentration of 0.3–1.5 wt.% is pumped into the formation, alkaline reagent with concentration of 1–30 wt.%, water with mineralization of up to 0.15 g/l — the rest, after pumping is squeezed with water with mineralization of up to 0.15 g/l in volume of 15 m³ and waterflooding is resumed. At mineralization from 0.15 g/l to 210 g/l, the composition is pumped into the formation by rims, in the first rim the composition containing surfactant with concentration of 0.05–0.5 wt.%, alkaline reagent with concentration of 1–15 wt.%, water with mineralization from 0.15 g/l to 210 g/l — balance, composition containing surfactant is pumped in the second rim with concentration of 0.5–1.5 wt.% and water with mineralization from 0.15 g/l to 210 g/l — balance, after pumping said rims, they are forced into the formation with water with mineralization from 0.15 g/l to 210 g/l in volume of 15 m³ and waterflooding is resumed. Surfactant used is STENOR APE 25.8.18 solution is a mixture of ethoxylated propoxylated alcohols of the C12-C15 fraction with isopropyl alcohol in a volume ratio of 1:1. Alkaline reagent used is 10 % sodium hydroxide solution.

EFFECT: proposed method of development of oil formation increases efficiency of development of oil carbonate formation due to increase of wetting capacity of injected composition containing surfactant, increasing oil-displacing capacity and, as a result, increasing oil recovery, as well as expanding technological capabilities of the method.

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