METHOD OF DEVELOPMENT OF DEPOSIT OF HIGH-VISCOSITY AND ULTRA-VISCOUS OIL BY THERMAL METHODS AT LATE STAGE OF DEVELOPMENT Russian patent published in 2020 - IPC E21B43/24 E21B43/22 E21B7/04 E21B47/06 

FIELD: oil, gas and coke-chemical industries.

SUBSTANCE: invention relates to oil industry. In the method of development of high-viscous and ultra-viscous oil deposit at the late stage of development, watering is determined in horizontal production wells and formation temperature. Pair of wells is selected - producing and located above horizontal discharge well with water cut of horizontal production well over 98 %. Pumping of steam in the selected horizontal injection well is stopped. Selected horizontal production well is converted to injection of produced water with the addition of a surfactant in amount of 30–180 m³/day at a temperature above the initial reservoir temperature of 30 °C or more but below vaporization conditions in the formation. Concentration of surfactant per 1 m³ of produced water is 0.1 to 10 % depending on temperature of pumped water produced. Simultaneously with injection of concomitant water with surfactant, temperature and pressure are measured in selected horizontal injection well. When the evaporation temperature in the selected horizontal injection well is reached, injection of associated water with SAS into the selected horizontal production well is stopped. After that selected horizontal injection well is switched over for product extraction. When the temperature drops by 5–10 % in the selected horizontal injection well, injection of by-produced water with SAS to the selected horizontal production well is resumed. While increasing water cut by 10–15 % and reducing temperature by 5–20 % in the selected horizontal injection well, reducing the amount of injection of associated water with surfactants by 15–25 % in the selected horizontal production well, while increasing water cut by 10–15 % and increasing temperature by 5–20 % in selected horizontal injection well, volume of injection of associated water with surfactant is increased by 15–25 % in selected horizontal production well.

EFFECT: technical result is higher efficiency of deposit development, prevention of breakthrough of produced water to well bottom, preservation of formation structure, alignment of front of oil displacement and increase of oil production.

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