COMPLEX POWDER COMPOSITION FOR STRUCTURED SPACER FLUID PREPARATION Russian patent published in 2012 - IPC C09K8/40 

FIELD: gas and oil production.

SUBSTANCE: invention refers to structured spacer fluids with adjustable density, applied in separation of backfilling and drilling slurry of different composition and density and in efficient displacement of drilling slurry from well cementing interval with abnormally high bed pressure (AHBP). Complex powder composition for structured spacer fluid preparation includes, wt %: the rest is lignin-alkaline agent of fraction composition, % at mesh sieve: N 0.9 - 2.12; N 0.315 - 22.35; N 0.08 - 34.10, N 0.08 and others are the rest; 80.0-85.0, carboxymethyl cellulose 15.0-20.0, nitrylotrimethylphosphonic acid 0.01- 0.15 above 100%.

EFFECT: increased quality of well bore preparation for cementing, improved cement contact with string and rock, bed separation quality in wells with AHBP.

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