METHOD FOR DEVELOPING HETEROGENOUS ULTRAVISCOUS OIL RESERVOIR Russian patent published in 2016 - IPC E21B43/24 E21B43/22 E21B7/04 

FIELD: oil and gas industry.

SUBSTANCE: invention can be used in developing heterogenous ultraviscous oil formations. Method comprises selecting section of formation with number of permeable intervals of more than 1 unit fraction. In central part of formation a horizontal steam well is drilled. At a distance of 1-5 m from formation bottom or water-oil contact a production horizontal well is drilled. Said wells are conditionally horizontal. Said wells are arranged so that contact area of each conditionally horizontal-shaft with oil saturated bed is not less than 0.5 of total surface of said horizontal shaft. Method includes calculation of thermal hydrodynamic model of propagation of boundaries of steam chamber after 10-15 years of steam pumping at maximum intake capacity of steam well. At a conditional point obtained in plan view at intersection of boundary of design steam chamber and a plane drawn perpendicular to horizontal shaft of steam well through its centre, main shaft of vertical well is drilled. Said well is then drilled with a smaller diameter not less than 3 side horizontal shafts of descending shape with coverage of design steam chamber not less than 70 % in both plan and profile. Well fan-like shape is obtained. Each of its shafts is provided with possibility of disconnection after flooding. Horizontal and fan wells are developed after drilling by injection of solvent in amount of 1-5 m³ per 1 m length of conditionally horizontal bores. For implementation of technology of steam assisted gravity drainage, steam is pumped into injection wells and product is extracted through production wells.

EFFECT: increasing oil recovery factor of heterogeneous oil formations.

1 cl, 2 ex, 2 dwg