METHOD FOR UNIFORM EXTRACTION STRATIFIED RESERVOIR Russian patent published in 2016 - IPC E21B43/20 E21B43/22 E21B43/32 

FIELD: oil and gas industry.

SUBSTANCE: invention can be used in developing heterogenous layered reservoirs. Method involves selection of producer and nearest injection well, which is reason of flooding of production well. Method includes pumping into well a composition for limiting water influx to eliminate water inrush zones. Water is pumped into injection well and product is extracted from production well. Composition for limiting water inflow is modified with water-water, concentration and ion composition of dissolved salts which is determined by laboratory research of reduction of permeability of core of given interlayer by not less than 10 times while pumping one porous volume of core at formation temperature and pumping rate of not less than 5 ml/min. Reduction of permeability is a result of precipitation of salts in bottomhole zone of production well during reaction of modified water with waste water of interlayer. Water cut of each interlayer is determined in production well. In injection and production well a string is lowered, having packers and said packers isolate interlayer with maximum water content from rest of interlayers. Modified water is pumped into isolated interlayer through injection well at a rate of 0.5-1.0 of maximum intake rate of interlayer. Bottom-hole pressure in production well is reduced to 0.9-1.0 of saturation pressure. Pumping is performed until water cut of interlayer is 0.8-1.2 of water cut of interlayer with minimum water cut. After that, through injection well in analysed interlayer aqueous solution of chlorine is pumped in amount of 20-100 m³ per 1 m effective thickness of interlayer. In first 10-50 m³ of injected modified water saline deposit inhibitors are added. Similar operation for successive pumping of modified water and aqueous chlorine solution is carried out on other interlayers except interlayer with minimum water cut. After that, wells are converted to normal operating mode. Said operations are repeated with periodicity of 0.5-2 year.

EFFECT: high uniformity of recovery of oil reserves, increasing sweep efficiency and oil recovery of layered oil deposits.

1 cl, 2 ex, 1 tbl, 1 dwg