METHOD OF FILTER CAKE REMOVAL OF BOTTOM HOLE AREA OF LOW-PERMEABLE LOW-TEMPERATURE TERRIGENOUS RESERVOIR Russian patent published in 2015 - IPC E21B43/22 E21B43/27 

FIELD: oil and gas industry.

SUBSTANCE: method of filter cake removal of bottom hole area of low-permeable low-temperature terrigenous reservoir located near the permafrost rocks comprises sequential injection through the column of oil-well tubing to the bottom hole area of mudded low-permeable low-temperature terrigenous reservoir of methanol in a volume of 1-2 m³ per 1 m of perforated thickness, phosphoric acid of 5-6% concentration with technological thermal equilibrium time of not more than 0.5 hours. Then aerated dispersed aqueous solution of hydrogen peroxide of low concentration of not more than 10-15 wt % is injected in the volume of 2-3 m³ per 1 m of the perforated thickness with forcing the orthophosphoric acid in a distal part of the reservoir. Then aerated dispersed aqueous solution of hydrogen peroxide is injected and forced again in the reservoir using the gas condensate with short-term technological thermal equilibrium time of not more than 0.5-1.0 h. Then removal and taking away of the remaining part of the aerated dispersed aqueous solution of hydrogen peroxide from the reservoir and the well to the surface is carried out. Then the well is developed by feeding to the well of inert gas, such as nitrogen, worked out, and the well is brought into production. At that injection of aerated dispersed aqueous solution of hydrogen peroxide is carried out by pulsed-cyclical method with alternate pumping the aqueous solution of hydrogen peroxide and inert gas, such as nitrogen.

EFFECT: increased permeability of dried bottom hole area of the reservoir, increase in the degree of filter cake removal of the bottom hole area and increase in productivity of the wells.

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