WELL KILLING FOAMING COMPOSITION Russian patent published in 2005 - IPC

FIELD: oil production industry, particularly foaming compositions for well killing and repair works performing in the case of abnormally low formation pressure.

SUBSTANCE: foaming composition comprises surfactant mixture including 25% aqueous solution of lignosulfate reagent, hydrocarbon liquid, peat and 20% aqueous solution of calcium chloride. Another surfactant mixture component is Acinetobacter Sp. biopolymer. All above substances are taken in the following amounts (% by weight): aqueous solution of lignosulfate reagent - 16-18, Acinetobacter Sp. biopolymer - 5-12, hydrocarbon liquid - 13-15, peat - 3-6, remainder is aqueous solution of calcium chloride. Above lignosulfate reagent is condensed spent sulfite-alcohol liquor or industrial powder lignosulfate.

EFFECT: increased efficiency of well killing due to usage of high expansion foam having low density and extended range of application thereof along with increased stability and blocking properties, possibility to kill wells formed in reservoirs with different permeability and in the case of reduced pressure of productive bed unblocking, which facilitates natural permeability maintaining and reduces well development time.

2 cl, 5 ex, 2 dwg, 1 tbl