METHOD FOR DEVELOPMENT OF STRATIFIED OIL DEPOSITS Russian patent published in 2014 - IPC E21B43/16 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to oil and gas industry and can be used for development of multilayer oil deposits presented by stratified heterogeneous reservoirs including stratified heterogeneous oil strata with high partitioning. It ensures increase in oil recovery from oil stratum with layer-by-layer heterogeneity notwithstanding location of layers with high permeability in total thickness of the oil stratum. The concept of the invention is as follows: the method includes drilling of the deposit through any of known grids of producing and injection wells, oil extraction from producing wells, pumping of the working fluid through injection wells, identification of layers with high and low permeability and liquidation of hydrodynamic connection of the producing well with highly permeable layer. According to the invention producing and injection wells are drilled to the whole thickness of the deposit. In process of oil extraction flow rate of the producing wells and water content of the product are controlled. When minimum profitable oil recovery rate is reached for each producing well a geophysical study is conducted in order to define current oil content. According to results of oil saturation assessment maximum depleted layers are defined which have high permeability and current oil content as close as possible to their residual oil content. Hydrodynamic connection is liquidated for producing wells with maximum depleted layers which is detected in the process of the wells operation. Then offshoots are made to the producing wells in low-permeable layers of the oil stratum. At that a number of offshoots, their length and diameter for each producing well are determined against geological and hydrodynamic model adapted to actual operating parameters of the wells on the basis of productivity index recovery at least to its initial value and increase in sweep efficiency for the oil stratum.

EFFECT: distributing offshoots in low-permeable layers of the oil stratum depending on location and number of maximum depleted layers.

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