DEVELOPMENT METHOD OF FRACTURED HIGH-VISCOSITY OIL DEPOSIT Russian patent published in 2013 - IPC E21B43/24 E21B7/04 

FIELD: oil and gas industry.

SUBSTANCE: development method of a fractured high-viscosity oil deposit involves drilling of vertical injection and branched horizontal production wells with horizontal shafts, pumping of a displacement fluid through vertical injection wells and extraction of the product through branched horizontal production wells. Vertical injection wells are drilled in a vorder zone of the deposit. Branches of horizontal shafts of production wells are drilled in an oil-bearing zone of the deposit with a stepped section. Number of branches corresponds to number of interlayers differing from each other with permeabilities by 1.5 and more times. Length of each branch is determined by means of a calculation depending on the formation permeability and length of the main horizontal shaft. Development of the deposit is performed at the formation pressure that is higher than saturation pressure of oil with gas and lower than pressure for fracture opening in the deposit by pumping to injection wells of a displacement agent (gas). Bottom-hole zones of production wells are periodically subject to steam treatment, when temperature of the extracted product is decreased to the temperature, below which abrupt increase in oil viscosity begins.

EFFECT: absence of breaks of displacement agent in fractures; performance of branched shafts from a horizontal well of optimum length; uniform displacement of the extracted product; increase in the deposit oil recovery.

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