OIL AND GAS WELL KILLING METHOD Russian patent published in 2006 - IPC E21B43/12 C09K8/42 

FIELD: oil and gas industry, particularly to kill wells for underground workover operation performing, adapted to be used in highly-permeable productive formations, in the case of high well fluid losses and high gas factor.

SUBSTANCE: method involves obtaining polyacrylamide cross-linked with ionizing radiation; injecting composition containing above polyacrylamide in well; injecting buffer liquid in well; additionally filling well with liquid. The cross-linked polyacrylamide is obtained by solid polyacrylamide treatment with 2.7-10 Mrad ionizing radiation dose. Above composition contains 5-40% suspension of above cross-linked polyacrylamide in organic liquid, namely in gas condensate, benzene or diethyleneglycol. Buffer liquid comprises 1.0-3.0% by weight of above polyacrylamide, 0.5-10.0% by weight of dispersed chalk or wood flour, 1.0-50.0 % by weight of at least one alcohol selected from lower monohydric, bihydric and trihydric alcohols, remainder is water, wherein water is preferably contained in the buffer liquid in amount of at least 50% by weight and methyl alcohol and diethylene glycol are used. Then well is filled with liquid, namely with 1-50% aqueous alcohol solution, wherein the alcohol is selected among monohydric, bihydric and trihydric alcohols.

EFFECT: increased efficiency of well killing drilled in highly-permeable formations.

3 cl, 1 ex, 1 tbl