METHOD OF GAS-CYCLE INJECTION OF LIQUID CARBON DIOXIDE AT SUPERCRITICAL CONDITIONS INTO OIL PRODUCING WELL Russian patent published in 2020 - IPC E21B43/16 

FIELD: oil, gas and coke-chemical industries.

SUBSTANCE: invention relates to methods of extracting hard-to-recover oil reserves of gas condensate. Method of gas-cycle injection of liquid carbon dioxide at supercritical conditions into oil producing well, including pumping of two fringes before and after pumping of carbon dioxide into production well, pumping of carbon dioxide with subsequent period of impregnation with carbon dioxide and initiation of oil production from the same production well at realization of gas-cyclic injection of carbon dioxide at supercritical conditions: at temperature more than T_crit = 31.1 °C and a pressure greater than P_crit = 7.38 MPa, prior to injection of carbon dioxide pumped into the well first rim hydrocarbon micellar solution in volume of 5–20 m³ per meter of treated perforation collector; carbon dioxide is then pumped under the above conditions and before the impregnation period pumped second rim containing hydrocarbon micellar solution and further gas permeability regulator and foaming agent in volume of 5–20 m³ per meter of treated perforation collector, after which the well is closed for a period of impregnation with subsequent production of oil from the same production well, wherein the number of pumping cycles in said sequence to the production well is not less than 1, wherein first fringe of hydrocarbon micellar solution contains at least one of: wt. %, finished mixture of secondary acyclic limit and unsaturated and aromatic hydrocarbons of general formula C₆-C₁₈ or Delta ASPGO (inhibitor of asphalt-resinous paraffin and hydrated deposits) composition, containing mixture of said hydrocarbons, 70–80, and a water-soluble nonionic surfactant of Neonol AF₉-12 20–30, and the second rim contains at least one of: wt. %, a ready mixture of secondary acyclic limit and unsaturated and aromatic hydrocarbons of general formula C₆-C₁₈ or Delta ASPGO composition containing a mixture of said hydrocarbons, 60–70, water-soluble nonionic surfactant Neonol AF₉-12 10–20; gas permeability regulator, at least one of oil-soluble polymers of said grades: Reapon, Diproxamine-157, FLO XL, Necadd-447, Turbulent Master 8010 5–10 and foaming agent of PO-RZF grade (6 %) 5–20.

EFFECT: technical result is increase in extraction of hard-to-recover oil and gas condensate reserves.

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