POLYMERIC DRILLING FLUID FOR EXPOSING PRODUCTION FORMATIONS Russian patent published in 2005 - IPC

FIELD: oil and gas production.

SUBSTANCE: polymeric drilling fluid comprises, wt %: xanthane-type biopolymer 0.3-0.5, polyanion cellulose (Drispac) 0.4-0.7, inhibiting additive 3.0-7.0, carbonate whitening agent 5.0-12.0, modifier 0.5-1.5, bactericide 0.1-0.2, complex organic additive (additional component) 0.5-1.0, foam suppressor 0.02-0.05, and water - the rest, wherein modifier is potassium salt of anionic acryl amide copolymer (Thermopass ^TM 34) or polyvinyl alcohol. Drilling fluid is applicable when boring horizontal holes or offshoots under various hydrogeological conditions.

EFFECT: increased removing and retention capacities of drilling fluid and reduced into-formation filterability at the same principal working parameters under salt attack and elevated temperature conditions.

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