METHOD FOR HETEROGENEOUS VISCOUS OIL BED DEVELOPMENT Russian patent published in 2015 - IPC E21B43/22 C09K8/582 

FIELD: oil and gas industry.

SUBSTANCE: invention refers to the oil and gas industry and can be used in developing heterogeneous terrigene or carbonate producing viscous-oil beds. In the method, which involves an oil bed water-flooding, injection of water solution banks containing alkali, a biopolymer, a surfactant, a bacterial culture and nutrient salts, into injection holes, and sampling of products from the production wells; deposit drilling is followed by mapping the formation permeability distribution in the wells with the formation permeability more than twice less than the average formation permeability; if the collected oil withdrawal is no more than 50% of the initial recovered reserves, the formation is hydraulically fractured; oil sampling findings are used to map the oil-viscosity compartment distribution; the above solution is injected in the compartments through the injection holes in the following proportions, wt %: alkali - no more than 5, biopolymer - no more than 1, surfactant - no more than 0.5, hydrocarbon-oxidising bacterial culture - no more than 0.1, nutrient salts - no more than 0.8, water - the rest with varying the concentration C of the ingredients in the above solution proportional to the specified OV for each C centre is determined depending on $$C_n^k=y_n\cdot C_{\max }^k,$$ wherein k is a type of the ingredient, n is number of the centre, y is a proportionality factor of each centre; y is calculated by a linear equation y=a·x+b, wherein x is the OV of the centre, mPa·s, a, b are linear equation factors determined if y for x_max equals to 1, and if x_min equals to 0 from a system of equations: wherein x_max and x_min are the maximum and minimum oil viscosities, respectively; injection cycles of the bank injection are repeated if an oil flow rate decreases to the pre-injection level.

EFFECT: higher displacement, coverage and recovery factors of the productive formation.

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