METHOD OF TREATING NON-UNIFORM PERMEABILITY OIL FORMATION Russian patent published in 2025 - IPC E21B43/22 E21B33/138 C09K8/42 C09K8/584 

FIELD: oil industry.

SUBSTANCE: method of treating a non-uniform permeability oil formation involves pumping into the non-uniform formation through an injection well a first solution – a blocking solution, which is a mixture of Neonol “АФ”9-6 or “ОП”-4 emulsifier and mineralized water with salt content of not less than 80 g/l, subsequent injection of mineralized waste water from the formation pressure maintenance system, monitoring formation permeability, pumping of the second solution – unblocking intensifying solution, which is a mixture of demulsifier, acids and fresh water, and then pumping of mineralized waste water from the formation pressure maintenance system. In the method, formation permeability is monitored during pumping of mineralized waste water and when its value is reduced by less than 30%, pumping of the first solution and mineralized water is repeated, and after reduction of permeability by 30% and more, the second solution is injected, wherein after the blocking composition, mineralized water is pumped in volume 3-10 times greater than the volume of the blocking composition. First solution contains, wt.%: Neonol “АФ”9-6 or “ОП”-4 0.02-0.05; mineralized water – the rest. Second solution contains Neonol “АФ”9-12, or “ОП”-7, or “ОП”-10 as a demulsifier, with the following ratio of components, wt.%: Neonol “АФ”9-12, or “ОП”-7, or “ОП”-10 0.01-0.1; HCl 5; acetic acid 5; fresh water is the rest.

EFFECT: levelling of displacement front, namely temporary blocking of well-receiving intervals of bottomhole formation zone with creation of conditions for increasing permeability of poorly drained intervals and with simultaneous removal of temporary blockade of receiving intervals.

1 cl, 4 tbl