COMPOSITION OF WELL-KILLING EMULSION POLYSACCHARIDE FLUID AND A METHOD FOR PREPARATION THEREOF Russian patent published in 2007 - IPC C09K8/42 

FIELD: special-destination fluids in oil and gas production industry.

SUBSTANCE: invention, in particular, relates to compositions of drilling fluids, perforation and rock-filling fluids, which may also be used to restrict water inflow in oil and gas wells. Composition of well-killing emulsion polysaccharide fluid comprising fresh or mineralized water, polysaccharide thickener, and hydrocarbon phase is characterized by that said hydrocarbon phase is selected from kerosene, diesel, and commercial petroleum, and by that composition further contains diethanolamine, boric cross-linking agent (SP-RD), and water-soluble surfactant: Neftenol VVD, Neftenol K or Neftenol ML. Composition suitably contains, wt %: water 15.00-35.00, diethanolamine 0.00-5.00, surfactant 0.50-6.00, polysaccharide thickener 0.05-0.30, cross-linking agent 0.05-0.30, and hydrocarbon phase - the rest. Preparation procedure comprises dissolving surfactant or, consecutively, diethanolamine and surfactant in fresh or demineralized water, adding hydrocarbon phase to form emulsion, dissolving and hydrating polysaccharide thickener in resulting emulsion, and adding cross-linking agent.

EFFECT: reduced density and filtrate loss allowing killing of wells with abnormally low formation pressure and high formation permeability so that well repair time can be shortened.

2 cl, 2 tbl, 6 ex