METHOD FOR WATERFLOODING PRODUCING RESERVOIRS OF MATURE OIL AND GAS POOLS Russian patent published in 2018 - IPC E21B43/20 

FIELD: soil or rock drilling.

SUBSTANCE: invention relates to the field of extraction of products from boreholes, and in particular to methods for enhanced production of hydrocarbons by the method of cyclic displacement with water. This method includes stationary injection of a displacing agent in injection wells, extracting oil from producing wells, recording field data on the operation of each of the wells, which determine the beginning of the introduction of the cyclic mode of injection of the displacing agent while increasing water cut, the cyclic injection mode is introduced without stopping the stationary injection mode, the upper limit of the duration of the injection cycle period is determined by the formula:

,

and the lower limit of the duration of the injection cycle period is determined on the basis of twice the time of the relaxation processes occurring in the productive formations of the rock of different lithotypes during the decays of cyclic injection, while the optimal pressure amplitude during cyclic injection is determined based on the expression:

,

where T^cycle – the duration of the injection cycle period, s, R is the distance between the injection and production wells, m, χ – the piezoconductivity coefficient of the reservoir, cm²/sec, δ – phase shift between the optimum amplitude of injection in the injection well and the maximum amplitude of production in the production well, rad, ε – reservoir hydraulic conductivity, Dcm/cP, q_max – maximum oil flow rate, cm³/sec, P_opt – optimum pressure amplitude at cyclic injection, MPa.

EFFECT: problem to be solved is to increase the oil recovery of producing wells due to the simultaneous use of stationary injection of a displacing agent with a cyclic mode of exposure.

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