METHOD OF DEVELOPMENT OF MULTIPAY OBJECT WITH HIGH-VISCOSITY OIL Russian patent published in 2016 - IPC E21B36/04 E21B43/24 E21B47/00 

FIELD: oil and gas industry.

SUBSTANCE: method of the development of a multipay object with high-viscosity oil includes drilling of production and injection wells, start-up of the electric heaters in the injection wells, injection of a cold working fluid in the injection wells, the working fluid heating using the well installed electric heaters. The heated working fluid is injected to the productive formations. The product is produced by the production wells. Wherein the object is selected, where any one of the formations has the viscosity over 200 mPa·s. To each productive formation from the vertical injection well side horizontal boreholes are drilled, or a multi-hole horizontal injection well with the horizontal boreholes directing in each formation is drilled. In the formation with the minimum permeability k_min the horizontal borehole is drilled with the length L_kmin, in other formations - in the proportion to the ratio of permeabilities as per the mathematical equation. All the horizontal boreholes are arranged parallel to the displacement front towards the production well. Water is used as the working fluid. In each horizontal borehole on a cable the bottom-hole heater with the power W_n is lowered ensuring the water temperature increasing in the given borehole to T_n, and gradually decreasing crude oil viscosity in each formation to the same value µ' with heated water injection. The temperature T_n is determined for the µ' values according to the diagrams of oil viscosity vs. temperature for each formation. The bottom-hole heaters are arranged in the centre of the central boreholes. Water is injected to the injection well through a heat insulated pipe with the packer installed in the annulus above the top productive formation. The injection process is performed by cycles with an injection period t_i and holding period t for water heating, wherein t ≥ t_i, for the injection period t_i the bottom-hole heaters are off, when the distance between the formations through the depth exceeds by more than 30 m. Injection is performed using equipment for a simultaneous-individual operation, the power W_n of the bottom-hole heaters is calculated as per the mathematical equation.

EFFECT: increased oil recovery of the oil pay.

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