METHOD FOR DEVELOPMENT OF PAIRED HORIZONTAL WELLS PRODUCING HIGH-VISCOSITY OIL Russian patent published in 2020 - IPC E21B43/24 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil industry and can be used in the development of a reservoir of high viscosity and bitumen oil. Invention comprises method for development of paired horizontal wells producing high viscosity oil. Method includes drilling of geological exploration wells for delineation of oil-saturated deposit and estimation of industrial development potential of deposit, construction of horizontal production and injection wells. Deposit is tested through geological survey wells. In production of oil inflow, its physical and chemical analysis is carried out, oil viscosity is determined in reservoir conditions. Depending on the viscosity value, a correction factor is used α to formula of steam volume calculation for pumping. Further, the production and injection wells are constructed. Injection well is located above and parallel to production well. Permeable zone is created between wells due to water vapor injection into both wells. After creating the permeable zone steam is supplied only to injection horizontal well. Product is extracted from production horizontal well. In horizontal borehole of the injection well geophysical investigations are carried out to determine oil saturation along the horizontal borehole. Thereafter, two columns of tubing string are arranged in the injection well. End of the column of smaller diameter is located at the beginning of the horizontal shaft, the end of the column of larger diameter – in the zone with oil saturation of more than 60 %. For injection of steam in production well one or two tubing string are arranged with displacement of end or ends along horizontal relative to ends of tubing string by at least 20 m. Prior to pumping of steam, initial liquid level and initial pressure in annular space of horizontal wells are measured. Volume of steam pumped by formula is pumped into both wells. During steam pumping to horizontal wells twice a week fluid and pressure levels in annular space are measured, dynamics of their change is monitored. When the pressure in the annular space exceeds value of 0.666*Pall, where Pall is the allowable pressure of reservoir integrity preservation of the oil-saturated deposit, the development of horizontal wells is stopped by steam pumping and the wells are transferred for thermocapillary impregnation and well shaft barrel cooling. In the production well thermo-barometric measurements are carried out by means of geophysical investigations. Geophysical survey results additionally define temperature distribution along horizontal shaft of production well. Pump and a fiber-optic cable run in on the tubing string are installed along the whole length of the filter. Pump is equipped at reception with temperature and pressure sensors. Then, steam is pumped through injection well. Product is sampled by a pump with the thermogram taken along the production well shaft by means of a fiber-optic cable and temperature measurement at the pump intake to control the uniform heating process of the production well. In presence of heating sections with temperature of more than 120 °C in interval of 300 m from the beginning of the filter zone in the production string the pump is installed 20 m before the filter part. In the absence of heating sections with temperature of more than 120 °C in interval of 300 m from the beginning of the filter zone is installed in production string 20 m before the filter part using the pipe-shank. When the liquid temperature drops below the maximum permissible value at the pump inlet steam injection through the injector is increased. As the temperature increases at the pump inlet, steam injection through injection well is reduced and / or the pump is switched to periodic operation mode. After stabilizing the temperature at the pump inlet equal to the maximum allowable by the operating conditions, the pump is switched to a constant operating mode.

EFFECT: increased oil production, reduced waiting period for research and introduction of downhole equipment, reduced risk of oil, gas and water ingress.

1 cl, 3 dwg, 1 tbl