METHODS AND COMPOSITIONS FOR TREATING WELLS Russian patent published in 2021 - IPC C09K8/524 C09K8/68 E21B43/22 

FIELD: oil industry.

SUBSTANCE: present invention relates to methods and compositions for use in subterranean operations to restore the permeability of a wellbore or an underground formation near a wellbore that has become impeded by sludge or tar deposits. A method of restoring the permeability of a wellbore located in underground environment wherein the wellbore contains one or several sludge deposits comprising a synthetic polymer and oil tar or byproduct thereof which envisages the steps: introducing an aqueous composition to a wellbore comprising an oxidizer (“ОВ”), a chelated metal activator and a surfactant (“SAS”) and contact of sludge deposits with the aqueous composition. Method for treating a sludge deposit comprising a synthetic polymer and oil tar or byproduct thereof in underground environment including a wellbore, envisages the steps: introducing an aqueous composition to a wellbore comprising an “ОВ”, the above-mentioned activator and “SAS” and contact of sludge deposits with the aqueous composition.

EFFECT: technical result consists in increase in efficiency of restoring the permeability of a wellbore in field conditions.

42 cl, 9 dwg, 11 ex, 3 tbl