METHOD FOR SELECTIVE CONTROL OF PERMEABILITY OF HETEROGENEOUS FORMATION Russian patent published in 2025 - IPC E21B33/138 E21B43/22 C09K8/584 

FIELD: obtaining oil from wells.

SUBSTANCE: invention relates to oil industry. In the method for selective control of permeability of a heterogeneous formation, a blocking composition is first pumped into the heterogeneous formation through an injection well – 0.02-5 wt.% surfactant solution with hydrophilic-lipophilic balance HLB of not more than 6 in mineralized water from reservoir pressure maintenance RPM system. Then, mineralized water is pumped from the RPM system for 1-3 days in an amount which is 3-10 times greater than the volume of the blocking composition. If the injectivity of the injection well has not decreased by 30% or more, then the injection of the blocking composition and then mineralized water from the RPM system is repeated. After injectivity of the injection well is reduced by 30% or more, 0.01-2 wt.% surfactant solution with HLB of at least 10 is injected in mineralized water from the RPM system. Then mineralized water is pumped from RPM system till injectivity is restored to not less than 70% of the initial one; if necessary, operations are repeated.

EFFECT: effective control of permeability of inhomogeneous formation of depleted deposits with mineralized water with minimum use of fresh water, selective increase in permeability of poorly drained intervals of the formation.

1 cl, 4 tbl, 4 ex