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

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil-producing industry. In method of development of high-viscous and ultra-viscous oil deposits by thermal methods at late stage of development horizontal steam-cyclic wells are located on deposit periphery, paired horizontal injection and production wells are placed in the central part of the deposit. In horizontal production wells there are temperature and pressure control devices. At the early stage of development, steam is pumped to horizontal steam-cyclic and paired horizontal injection and production wells for heating of the productive formation, steam supply is stopped for thermocapillary impregnation of deposit, then horizontal production wells are changed for product selection, horizontal injection wells – for steam injection. Horizontal steam-cyclic wells are operated with cycles – successive injection of steam and extraction of products. At the late stage of development, horizontal steam-cycle and paired horizontal injection and production wells are selected with unprofitable yield – with a steam-oil ratio of more than 10. In the above unprofitable horizontal steam-cycle and horizontal injection wells there performed is controlled reduction of steam pumping volume excluding sudden pressure drop – more than 0.05 MPa/day and temperature – more than 1 °C/day in steam chamber to temperature of water evaporation at initial pressure in formation. Said unprofitable horizontal steam-cycle wells are converted to hot water injection, and said unprofitable horizontal injection wells for gas injection. When waterflooding in said unprofitable horizontal production wells is 98 % or more, they are also transferred for gas injection.

EFFECT: increased efficiency of development of high-viscous and ultra-viscous oil deposit at the late stage of development due to expansion of the area of thermal impact with simultaneous reduction of costs, controlled completion of the deposit development with preservation of the reservoir structure, expansion of technological capabilities.

1 cl, 2 dwg