METHOD OF THERMOCHEMICAL PROCESSING OF OIL POOL (OPTIONS) Russian patent published in 2018 - IPC E21B43/24 E21B43/22 E21B33/138 C09K8/524 C09K8/592 

FIELD: oil and gas industry.

SUBSTANCE: group of inventions refers to the oil industry. In the method for thermochemical treatment of an oil pool, the water cut of the production of the well is predetermined, at water cut of production from 20 to 59 % in the first variant sequential injection of a hydrocarbon solvent and thermochemical composition into the production well is carried out. As the thermochemical composition, an aqueous solution of sodium nitrite is pumped at the following component ratio, mass%: sodium nitrite 4–32, water – the rest, and an aqueous solution of a reaction initiator with the following component ratio, wt%: sulfamic acid 5–40, alkaline reagent 2–16, water – the rest. Volume ratio of said aqueous solutions is 1:1, the mass ratio of sodium nitrite to sulfamic acid is 1:1.25, the mass ratio of sulfamic acid and alkaline reagent is 2.5:1. Then the process is held for 3 to 48 hours, after which the well is developed. According to the second variant of the method, when the product is water-cut from 60 to 99.9 %, a gelling composition is injected into the production well at the following component ratio, mass%: polyacrylamide 0.3–1.5; stapler 0.03–0.15; water – the rest, the gel-forming composition is pushed into the reservoir with a technological liquid with a density corresponding to the density of the jamming liquid, the process is carried out for a gelation of 24 hours, sequential injection of the hydrocarbon solvent and the above-mentioned thermochemical composition is carried out, then a technological aging of 3 to 48 hours is carried out, after which the well is developed. In a third variant, the above-mentioned gelling composition is injected, it is pushed into the formation by a process liquid with a density corresponding to the density of the injected water, a technological aging is carried out for a gelation of 24 hours, then the injection of the above-mentioned thermochemical composition is carried out, then the polymer composition is pumped at the following component ratio, by weight: polyacrylamide 0.05–0.3; joiner 0.005–0.03; water – the rest, is pushed into the reservoir with a technological fluid with a density corresponding to the density of the injected water, and waterflooding is resumed.

EFFECT: directed thermochemical impact on oil-saturated interlayers, connection to the development of oil-rich, low-permeability zones previously unseen, increase of formation coverage by thermal impact, enhanced oil recovery.

3 cl, 3 tbl, 3 ex