DEVELOPMENT METHOD OF HIGH-VISCOSITY OIL DEPOSIT IN MULTIPLE-FORMATION LAYER-BY-LAYER NONHOMOGENEOUS HEADER Russian patent published in 2012 - IPC E21B43/24 

FIELD: oil and gas industry.

SUBSTANCE: method involves drilling of horizontal and vertical injection and production wells, steam pumping to the formation through horizontal well and heating of high-viscosity oil and its extraction. Besides, steam pumping and product extraction is performed simultaneously. Horizontal wells are made in the form of a pair of injection and production wells, the horizontal sections of which are arranged in parallel one above the other in vertical plane and made in the form of a sinewave with intersection of all formations in multiple-formation layer-by-layer nonhomogeneous header. Then, vertical wells are drilled in pairs on both sides of vertical plane of horizontal wells in zones of maximum approximation of horizontal sections of horizontal wells in the roof and bottom of deposit. Drilling in vertical injection wells is performed in lower part of multiple-formation deposit, and in vertical production wells - in upper part of deposit. Besides, opening sections of vertical injection wells shall be made at the distance of not less than 5 m to lower horizontal section, and opening sections in vertical production wells shall have the height of not less than half of the deposit thickness. The deposit is heated by steam pumping to both wells with formation of steam chamber and heating of inter-well zone with reduction of oil viscosity. Steam is pumped to upper horizontal injection well and product is extracted from lower production horizontal well. Then, steam is pumped simultaneously to horizontal injection well and to vertical injection wells to maximum approximation zones of sections of horizontal wells to the deposit bottom. Product extraction is performed simultaneously from horizontal production well and from vertical production wells located in maximum approximation zones of horizontal sections in the deposit roof. Besides, monitoring of process parameters of the deposit and wells is performed during product extraction; periodic determination of mineral content of incidentally extracted water, analysis of effect of the change of mineral content of incidentally extracted water on uniform heating of steam chamber is performed. Considering the change of mineral content of incidentally extracted water, uniform warm-up of steam chamber is performed by controlling the steam pumping or well product extraction mode till stable mineral content value of incidentally extracted water is achieved. Steam pumping and product extraction is performed simultaneously.

EFFECT: increasing the efficiency of the method owing to enlarging the formation heating area and reducing the development period.

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