PROCEDURE FOR WELL KILLING Russian patent published in 2011 - IPC E21B43/22 

FIELD: oil and gas production.

SUBSTANCE: procedure for well killing consists in pumping invert-emulsion solution -IES, spacer fluid, and blocking fluid. As spacer fluid there is used viscoelastic liquid of the following composition, kg/m³: oxy-ethyl-cellulose 5-10, sodium hydroxide 1-3, chromium acetate 2-4, water - the rest; and blocking liquid of the following composition, wt %: acyclic acid of common formula C_nH_2n-mO₂, where m is -2 or 4, or 6, 18.0-24.0, poly-methyl-meta-acrylate 2.0-3.0, granulated mineral filler in mixture with fibrous and laminar fillers 30.0-50.0, 30 % solution of caustic soda 13.1-15.0, hydrocarbon base - the rest and IES of composition, wt %: stable gas condensate 40-50, calcium chloride 8-12, emulsifier 5-10, water - the rest. IES is pumped before spacer and squeezing liquids pumping. Also, spacer fluid is prepared and pumped so, that it acquires viscoelastic properties directly at wellhead.

EFFECT: increased efficiency of well killing.

2 cl, 3 ex, 1 tbl