METHOD TO REMOVE POLYMER-CLAY MUDDING COMPOSITIONS FROM PRODUCING BED Russian patent published in 2007 - IPC E21B43/27 

FIELD: oil and gas industry, particularly dissolving minerals other than hydrocarbons for oil and gas well overhaul repair to increase well output.

SUBSTANCE: method involves injecting processing mix including strong acid salt, surfactant and water, in bed; holding it in bed to provide reaction; removing reaction products from well and operating well. The strong acid salt included in the processing mix is acid univalent inorganic cation fluoride. Above substances are taken in the following amounts: acid univalent inorganic cation fluoride - 10-20% by weight, surfactant - 0.2-1.5% by weight, remainder is water. Processing mix volume is not less than mudded zone pore volume. After well treatment with the use of above mix well is drained for 8-20 hours by creation of 10-14 depression-repression cycles. Then well is brought into operation. At temperature exceeding 60°C univalent inorganic cation hydroxide is additionally added to the processing mix in amount of 6-8% by weight.

EFFECT: possibility to recover producing bed permeability up to value close to initial one due to mudding composition removal by disintegration thereof.

2 cl, 1 ex, 2 tbl